XML/XPath: Difference between revisions

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Perform the following three XPath queries on the XML Document below:
Perform the following three XPath queries on the XML Document below:
* Retrieve the first "item" element
* '''//item[1]''': Retrieve the first "item" element
* Perform an action on each "price" element (print it out)
* '''//price/text()''': Perform an action on each "price" element (print it out)
* Get an array of all the "name" elements
* '''//name''': Get an array of all the "name" elements


XML Document:
XML Document:
Line 33: Line 33:
</section>
</section>
</inventory>
</inventory>
=={{header|AutoHotkey}}==
With regular expressions
<lang AutoHotkey>FileRead, inventory, xmlfile.xml


=={{header|AArch64 Assembly}}==
RegExMatch(inventory, "<item.*?</item>", item1)
{{works with|as|Raspberry Pi 3B version Buster 64 bits}}
MsgBox % item1
<syntaxhighlight lang="aarch64 assembly">
/* ARM assembly AARCH64 Raspberry PI 3B */
/* program xpathXml64.s */
/*******************************************/
/* Constantes file */
/*******************************************/
/* for this file see task include a file in language AArch64 assembly*/
.include "../includeConstantesARM64.inc"
.equ NBMAXELEMENTS, 100
/*******************************************/
/* Structures */
/********************************************/
/* structure xmlNode*/
.struct 0
xmlNode_private: // application data
.struct xmlNode_private + 8
xmlNode_type: // type number, must be second !
.struct xmlNode_type + 8
xmlNode_name: // the name of the node, or the entity
.struct xmlNode_name + 8
xmlNode_children: // parent->childs link
.struct xmlNode_children + 8
xmlNode_last: // last child link
.struct xmlNode_last + 8
xmlNode_parent: // child->parent link
.struct xmlNode_parent + 8
xmlNode_next: // next sibling link
.struct xmlNode_next + 8
xmlNode_prev: // previous sibling link
.struct xmlNode_prev + 8
xmlNode_doc: // the containing document
.struct xmlNode_doc + 8
xmlNode_ns: // pointer to the associated namespace
.struct xmlNode_ns + 8
xmlNode_content: // the content
.struct xmlNode_content + 8
xmlNode_properties: // properties list
.struct xmlNode_properties + 8
xmlNode_nsDef: // namespace definitions on this node
.struct xmlNode_nsDef + 8
xmlNode_psvi: // for type/PSVI informations
.struct xmlNode_psvi + 8
xmlNode_line: // line number
.struct xmlNode_line + 4
xmlNode_extra: // extra data for XPath/XSLT
.struct xmlNode_extra + 4
xmlNode_fin:
/********************************************/
/* structure xmlNodeSet*/
.struct 0
xmlNodeSet_nodeNr: // number of nodes in the set
.struct xmlNodeSet_nodeNr + 4
xmlNodeSet_nodeMax: // size of the array as allocated
.struct xmlNodeSet_nodeMax + 4
xmlNodeSet_nodeTab: // array of nodes in no particular order
.struct xmlNodeSet_nodeTab + 8
xmlNodeSet_fin:
/********************************************/
/* structure xmlXPathObject*/
.struct 0
xmlPathObj_type: //
.struct xmlPathObj_type + 8
xmlPathObj_nodesetval: //
.struct xmlPathObj_nodesetval + 8
xmlPathObj_boolval: //
.struct xmlPathObj_boolval + 8
xmlPathObj_floatval: //
.struct xmlPathObj_floatval + 8
xmlPathObj_stringval: //
.struct xmlPathObj_stringval + 8
xmlPathObj_user: //
.struct xmlPathObj_user + 8
xmlPathObj_index: //
.struct xmlPathObj_index + 8
xmlPathObj_usex2: //
.struct xmlPathObj_usex2 + 8
xmlPathObj_index2: //
.struct xmlPathObj_index2 + 8
/*********************************/
/* Initialized data */
/*********************************/
.data
szMessEndpgm: .asciz "\nNormal end of program.\n"
szMessDisVal: .asciz "\nDisplay set values.\n"
szMessDisArea: .asciz "\nDisplay area values.\n"
szFileName: .asciz "testXml.xml"
szMessError: .asciz "Error detected !!!!. \n"
szLibName: .asciz "name"
szLibPrice: .asciz "//price"
szLibExtName: .asciz "//name"
szCarriageReturn: .asciz "\n"
/*********************************/
/* UnInitialized data */
/*********************************/
.bss
.align 4
tbExtract: .skip 8 * NBMAXELEMENTS // result extract area
/*********************************/
/* code section */
/*********************************/
.text
.global main
main: // entry of program
ldr x0,qAdrszFileName
bl xmlParseFile // create doc
cbz x0,99f // error ?
mov x19,x0 // doc address
mov x0,x19 // doc
bl xmlDocGetRootElement // get root
bl xmlFirstElementChild // get first section
bl xmlFirstElementChild // get first item
bl xmlFirstElementChild // get first name
bl xmlNodeGetContent // extract content
bl affichageMess // for display
ldr x0,qAdrszCarriageReturn
bl affichageMess
ldr x0,qAdrszMessDisVal
bl affichageMess
mov x0,x19
ldr x1,qAdrszLibPrice // extract prices
bl extractValue
mov x0,x19
ldr x1,qAdrszLibExtName // extract names
bl extractValue
ldr x0,qAdrszMessDisArea
bl affichageMess
mov x4,#0 // display string result area
ldr x5,qAdrtbExtract
1:
ldr x0,[x5,x4,lsl #3]
cbz x0,2f
bl affichageMess
ldr x0,qAdrszCarriageReturn
bl affichageMess
add x4,x4,1
b 1b
2:
mov x0,x19
bl xmlFreeDoc
bl xmlCleanupParser
ldr x0,qAdrszMessEndpgm
bl affichageMess
b 100f
99: // error
ldr x0,qAdrszMessError
bl affichageMess
100: // standard end of the program
mov x0,0 // return code
mov x8,EXIT // request to exit program
svc 0 // perform the system call
qAdrszMessError: .quad szMessError
qAdrszMessEndpgm: .quad szMessEndpgm
qAdrszLibName: .quad szLibName
qAdrszLibPrice: .quad szLibPrice
qAdrszCarriageReturn: .quad szCarriageReturn
qAdrszFileName: .quad szFileName
qAdrszLibExtName: .quad szLibExtName
qAdrtbExtract: .quad tbExtract
qAdrszMessDisVal: .quad szMessDisVal
qAdrszMessDisArea: .quad szMessDisArea
/******************************************************************/
/* extract value of set */
/******************************************************************/
/* x0 contains the doc address
/* x1 contains the address of the libel to extract */
extractValue:
stp x19,lr,[sp,-16]! // save registers
stp x20,x21,[sp,-16]! // save registers
stp x22,x23,[sp,-16]! // save registers
mov x20,x1 // save address libel
mov x19,x0 // save doc
bl xmlXPathNewContext // create context
mov x23,x0 // save context
mov x1,x0
mov x0,x20
bl xmlXPathEvalExpression
mov x21,x0
mov x0,x23
bl xmlXPathFreeContext // free context
cmp x21,#0
beq 100f
ldr x14,[x21,#xmlPathObj_nodesetval] // values set
ldr w23,[x14,#xmlNodeSet_nodeNr] // set size
mov x22,#0 // index
ldr x20,[x14,#xmlNodeSet_nodeTab] // area of nodes
ldr x21,qAdrtbExtract
1: // start loop
ldr x3,[x20,x22,lsl #3] // load node
mov x0,x19
ldr x1,[x3,#xmlNode_children] // load string value
mov x2,#1
bl xmlNodeListGetString
str x0,[x21,x22,lsl #3] // store string pointer in area
bl affichageMess // and display string result
ldr x0,qAdrszCarriageReturn
bl affichageMess
add x22,x22,1
cmp x22,x23
blt 1b
100:
ldp x22,x23,[sp],16 // restaur 2 registers
ldp x20,x21,[sp],16 // restaur 2 registers
ldp x19,lr,[sp],16 // restaur 2 registers
ret // return to address lr x30
/********************************************************/
/* File Include fonctions */
/********************************************************/
/* for this file see task include a file in language AArch64 assembly */
.include "../includeARM64.inc"
</syntaxhighlight>
{{output}}
<pre>
Invisibility Cream


Display set values.
pos = 1
14.50
While, pos := RegExMatch(inventory, "<price>(.*?)</price>", price, pos + 1)
23.99
MsgBox % price1
4.95
3.56
Invisibility Cream
Levitation Salve
Blork and Freen Instameal
Grob winglets


Display area values.
While, pos := RegExMatch(inventory, "<name>.*?</name>", name, pos + 1)
Invisibility Cream
names .= name . "`n"
Levitation Salve
MsgBox % names</lang>
Blork and Freen Instameal
{{libheader|AHK XPath}}
Grob winglets
<lang AutoHotkey>#Include xpath.ahk


Normal end of program.
xpath_load(doc, "xmlfile.xml")

; Retrieve the first "item" element
MsgBox % xpath(doc, "/inventory/section[1]/item[1]/text()")

; Perform an action on each "price" element (print it out)
prices := xpath(doc, "/inventory/section/item/price/text()")
Loop, Parse, prices,`,
reordered .= A_LoopField "`n"
MsgBox % reordered

; Get an array of all the "name" elements
MsgBox % xpath(doc, "/inventory/section/item/name")</lang>


</pre>


=={{header|AppleScript}}==
=={{header|AppleScript}}==
Line 70: Line 284:
''AppleScript has no-built in support for XPath, but it could be used via a 'do shell script' command. Here's a solution using Apple System Events.
''AppleScript has no-built in support for XPath, but it could be used via a 'do shell script' command. Here's a solution using Apple System Events.


<lang AppleScript>set theXMLdata to "<inventory title=\"OmniCorp Store #45x10^3\">
<syntaxhighlight lang="applescript">set theXMLdata to "<inventory title=\"OmniCorp Store #45x10^3\">
<section name=\"health\">
<section name=\"health\">
<item upc=\"123456789\" stock=\"12\">
<item upc=\"123456789\" stock=\"12\">
Line 130: Line 344:
return my getElementValuesByName(xmlData's contents, "price") -- Solution to part 3 of problem.
return my getElementValuesByName(xmlData's contents, "price") -- Solution to part 3 of problem.
end tell</lang>Output for the three results (respectively):<lang AppleScript>"<item upc=\"123456789\" stock=\"12\">
end tell</syntaxhighlight>Output for the three results (respectively):<syntaxhighlight lang="applescript">"<item upc=\"123456789\" stock=\"12\">
<name>Invisibility Cream</name>
<name>Invisibility Cream</name>
<price>14.50</price>
<price>14.50</price>
Line 138: Line 352:
{"Invisibility Cream", "Levitation Salve", "Blork and Freen Instameal", "Grob winglets"}
{"Invisibility Cream", "Levitation Salve", "Blork and Freen Instameal", "Grob winglets"}


{"14.50", "23.99", "4.95", "3.56"}</lang>
{"14.50", "23.99", "4.95", "3.56"}</syntaxhighlight>

=={{header|ARM Assembly}}==
{{works with|as|Raspberry Pi}}
<syntaxhighlight lang="arm assembly">
/* ARM assembly Raspberry PI */
/* program xpathXml.s */

/* Constantes */
.equ STDOUT, 1 @ Linux output console
.equ EXIT, 1 @ Linux syscall
.equ WRITE, 4 @ Linux syscall

.equ NBMAXELEMENTS, 100

/*******************************************/
/* Structures */
/********************************************/
/* structure xmlNode*/
.struct 0
xmlNode_private: @ application data
.struct xmlNode_private + 4
xmlNode_type: @ type number, must be second !
.struct xmlNode_type + 4
xmlNode_name: @ the name of the node, or the entity
.struct xmlNode_name + 4
xmlNode_children: @ parent->childs link
.struct xmlNode_children + 4
xmlNode_last: @ last child link
.struct xmlNode_last + 4
xmlNode_parent: @ child->parent link
.struct xmlNode_parent + 4
xmlNode_next: @ next sibling link
.struct xmlNode_next + 4
xmlNode_prev: @ previous sibling link
.struct xmlNode_prev + 4
xmlNode_doc: @ the containing document
.struct xmlNode_doc + 4
xmlNode_ns: @ pointer to the associated namespace
.struct xmlNode_ns + 4
xmlNode_content: @ the content
.struct xmlNode_content + 4
xmlNode_properties: @ properties list
.struct xmlNode_properties + 4
xmlNode_nsDef: @ namespace definitions on this node
.struct xmlNode_nsDef + 4
xmlNode_psvi: @ for type/PSVI informations
.struct xmlNode_psvi + 4
xmlNode_line: @ line number
.struct xmlNode_line + 4
xmlNode_extra: @ extra data for XPath/XSLT
.struct xmlNode_extra + 4
xmlNode_fin:
/********************************************/
/* structure xmlNodeSet*/
.struct 0
xmlNodeSet_nodeNr: @ number of nodes in the set
.struct xmlNodeSet_nodeNr + 4
xmlNodeSet_nodeMax: @ size of the array as allocated
.struct xmlNodeSet_nodeMax + 4
xmlNodeSet_nodeTab: @ array of nodes in no particular order
.struct xmlNodeSet_nodeTab + 4
xmlNodeSet_fin:
/********************************************/
/* structure xmlXPathObject*/
.struct 0
xmlPathObj_type: @
.struct xmlPathObj_type + 4
xmlPathObj_nodesetval: @
.struct xmlPathObj_nodesetval + 4
xmlPathObj_boolval: @
.struct xmlPathObj_boolval + 4
xmlPathObj_floatval: @
.struct xmlPathObj_floatval + 4
xmlPathObj_stringval: @
.struct xmlPathObj_stringval + 4
xmlPathObj_user: @
.struct xmlPathObj_user + 4
xmlPathObj_index: @
.struct xmlPathObj_index + 4
xmlPathObj_user2: @
.struct xmlPathObj_user2 + 4
xmlPathObj_index2: @
.struct xmlPathObj_index2 + 4



/*********************************/
/* Initialized data */
/*********************************/
.data
szMessEndpgm: .asciz "\nNormal end of program.\n"
szMessDisVal: .asciz "\nDisplay set values.\n"
szMessDisArea: .asciz "\nDisplay area values.\n"
szFileName: .asciz "testXml.xml"
szMessError: .asciz "Error detected !!!!. \n"


szLibName: .asciz "name"
szLibPrice: .asciz "//price"
szLibExtName: .asciz "//name"
szCarriageReturn: .asciz "\n"


/*********************************/
/* UnInitialized data */
/*********************************/
.bss
.align 4
tbExtract: .skip 4 * NBMAXELEMENTS @ result extract area
/*********************************/
/* code section */
/*********************************/
.text
.global main
main: @ entry of program
ldr r0,iAdrszFileName
bl xmlParseFile @ create doc
mov r9,r0 @ doc address
mov r0,r9 @ doc
bl xmlDocGetRootElement @ get root
bl xmlFirstElementChild @ get first section
bl xmlFirstElementChild @ get first item
bl xmlFirstElementChild @ get first name
bl xmlNodeGetContent @ extract content
bl affichageMess @ for display
ldr r0,iAdrszCarriageReturn
bl affichageMess

ldr r0,iAdrszMessDisVal
bl affichageMess
mov r0,r9
ldr r1,iAdrszLibPrice @ extract prices
bl extractValue
mov r0,r9
ldr r1,iAdrszLibExtName @ extact names
bl extractValue
ldr r0,iAdrszMessDisArea
bl affichageMess
mov r4,#0 @ display string result area
ldr r5,iAdrtbExtract
1:
ldr r0,[r5,r4,lsl #2]
cmp r0,#0
beq 2f
bl affichageMess
ldr r0,iAdrszCarriageReturn
bl affichageMess
add r4,#1
b 1b

2:
mov r0,r9
bl xmlFreeDoc
bl xmlCleanupParser
ldr r0,iAdrszMessEndpgm
bl affichageMess
b 100f
99:
@ error
ldr r0,iAdrszMessError
bl affichageMess
100: @ standard end of the program
mov r0, #0 @ return code
mov r7, #EXIT @ request to exit program
svc #0 @ perform the system call

iAdrszMessError: .int szMessError
iAdrszMessEndpgm: .int szMessEndpgm
iAdrszLibName: .int szLibName
iAdrszLibPrice: .int szLibPrice
iAdrszCarriageReturn: .int szCarriageReturn
iAdrszFileName: .int szFileName
iAdrszLibExtName: .int szLibExtName
iAdrtbExtract: .int tbExtract
iAdrszMessDisVal: .int szMessDisVal
iAdrszMessDisArea: .int szMessDisArea
/******************************************************************/
/* extract value of set */
/******************************************************************/
/* r0 contains the doc address
/* r1 contains the address of the libel to extract */
extractValue:
push {r1-r10,lr} @ save registres
mov r4,r1 @ save address libel
mov r9,r0 @ save doc
ldr r8,iAdrtbExtract
bl xmlXPathNewContext @ create context
mov r10,r0
mov r1,r0
mov r0,r4
bl xmlXPathEvalExpression
mov r5,r0
mov r0,r10
bl xmlXPathFreeContext @ free context
cmp r5,#0
beq 100f
ldr r4,[r5,#xmlPathObj_nodesetval] @ values set
ldr r6,[r4,#xmlNodeSet_nodeNr] @ set size
mov r7,#0 @ index
ldr r4,[r4,#xmlNodeSet_nodeTab] @ area of nods
1: @ start loop
ldr r3,[r4,r7,lsl #2] @ load node
mov r0,r9
ldr r1,[r3,#xmlNode_children] @ load string value
mov r2,#1
bl xmlNodeListGetString
str r0,[r8,r7,lsl #2] @ store string pointer in area
bl affichageMess @ and display string result
ldr r0,iAdrszCarriageReturn
bl affichageMess
add r7,#1
cmp r7,r6
blt 1b
100:
pop {r1-r10,lr} @ restaur registers */
bx lr @ return

/******************************************************************/
/* display text with size calculation */
/******************************************************************/
/* r0 contains the address of the message */
affichageMess:
push {r0,r1,r2,r7,lr} @ save registres
mov r2,#0 @ counter length
1: @ loop length calculation
ldrb r1,[r0,r2] @ read octet start position + index
cmp r1,#0 @ if 0 its over
addne r2,r2,#1 @ else add 1 in the length
bne 1b @ and loop
@ so here r2 contains the length of the message
mov r1,r0 @ address message in r1
mov r0,#STDOUT @ code to write to the standard output Linux
mov r7, #WRITE @ code call system "write"
svc #0 @ call systeme
pop {r0,r1,r2,r7,lr} @ restaur registers */
bx lr @ return

</syntaxhighlight>
{{output}}
<pre>
Invisibility Cream

Display set values.
14.50
23.99
4.95
3.56
Invisibility Cream
Levitation Salve
Blork and Freen Instameal
Grob winglets

Display area values.
Invisibility Cream
Levitation Salve
Blork and Freen Instameal
Grob winglets

Normal end of program.

</pre>

=={{header|AutoHotkey}}==
With regular expressions
<syntaxhighlight lang="autohotkey">FileRead, inventory, xmlfile.xml

RegExMatch(inventory, "<item.*?</item>", item1)
MsgBox % item1

pos = 1
While, pos := RegExMatch(inventory, "<price>(.*?)</price>", price, pos + 1)
MsgBox % price1

While, pos := RegExMatch(inventory, "<name>.*?</name>", name, pos + 1)
names .= name . "`n"
MsgBox % names</syntaxhighlight>
{{libheader|AHK XPath}}
<syntaxhighlight lang="autohotkey">#Include xpath.ahk

xpath_load(doc, "xmlfile.xml")

; Retrieve the first "item" element
MsgBox % xpath(doc, "/inventory/section[1]/item[1]/text()")

; Perform an action on each "price" element (print it out)
prices := xpath(doc, "/inventory/section/item/price/text()")
Loop, Parse, prices,`,
reordered .= A_LoopField "`n"
MsgBox % reordered

; Get an array of all the "name" elements
MsgBox % xpath(doc, "/inventory/section/item/name")</syntaxhighlight>

=={{header|Bracmat}}==
<syntaxhighlight lang="bracmat">{Retrieve the first "item" element}
( nestML$(get$("doc.xml",X,ML))
: ?
( inventory
. ?,? (section.?,? ((item.?):?item) ?) ?
)
?
& out$(toML$!item)
)

{Perform an action on each "price" element (print it out)}
( nestML$(get$("doc.xml",X,ML))
: ?
( inventory
. ?
, ?
( section
. ?
, ?
( item
. ?
, ?
( price
. ?
, ?price
& out$!price
& ~
)
?
)
?
)
?
)
?
|
)

{Get an array of all the "name" elements}
( :?anArray
& nestML$(get$("doc.xml",X,ML))
: ?
( inventory
. ?
, ?
( section
. ?
, ?
( item
. ?
, ?
( name
. ?
, ?name
& !anArray !name:?anArray
& ~
)
?
)
?
)
?
)
?
| out$!anArray {Not truly an array, but a list.}
);</syntaxhighlight>

=={{header|C}}==
{{libheader|LibXML}}
Takes XML document and XPath expression as inputs and prints results, usage is printed if invoked incorrectly.
<syntaxhighlight lang="c">
#include <libxml/parser.h>
#include <libxml/xpath.h>

xmlDocPtr getdoc (char *docname) {
xmlDocPtr doc;
doc = xmlParseFile(docname);

return doc;
}

xmlXPathObjectPtr getnodeset (xmlDocPtr doc, xmlChar *xpath){
xmlXPathContextPtr context;
xmlXPathObjectPtr result;

context = xmlXPathNewContext(doc);

result = xmlXPathEvalExpression(xpath, context);
xmlXPathFreeContext(context);

return result;
}

int main(int argc, char **argv) {

if (argc <= 2) {
printf("Usage: %s <XML Document Name> <XPath expression>\n", argv[0]);
return 0;
}
char *docname;
xmlDocPtr doc;
xmlChar *xpath = (xmlChar*) argv[2];
xmlNodeSetPtr nodeset;
xmlXPathObjectPtr result;
int i;
xmlChar *keyword;

docname = argv[1];
doc = getdoc(docname);
result = getnodeset (doc, xpath);
if (result) {
nodeset = result->nodesetval;
for (i=0; i < nodeset->nodeNr; i++) {
xmlNodePtr titleNode = nodeset->nodeTab[i];
keyword = xmlNodeListGetString(doc, titleNode->xmlChildrenNode, 1);
printf("Value %d: %s\n",i+1, keyword);
xmlFree(keyword);
}
xmlXPathFreeObject (result);
}
xmlFreeDoc(doc);
xmlCleanupParser();
return 0;
}
</syntaxhighlight>
testXML.xml contains the XML mentioned in the task description. Code must be compiled with the correct flags.
<pre>
C:\rosettaCode>xPather.exe testXML.xml //price
Value 1: 14.50
Value 2: 23.99
Value 3: 4.95
Value 4: 3.56

C:\rosettaCode>xPather.exe testXML.xml //name
Value 1: Invisibility Cream
Value 2: Levitation Salve
Value 3: Blork and Freen Instameal
Value 4: Grob winglets
</pre>


=={{header|C sharp}}==
=={{header|C sharp}}==
<lang csharp>XmlReader XReader;
<syntaxhighlight lang="csharp">XmlReader XReader;
// Either read the xml from a string ...
// Either read the xml from a string ...
Line 182: Line 831:
// Convert the generic list to an array and output the count of items.
// Convert the generic list to an array and output the count of items.
Console.WriteLine(NodesValues.ToArray().Length);</lang>
Console.WriteLine(NodesValues.ToArray().Length);</syntaxhighlight>


=={{header|C++}}==
=={{header|C++}}==

{{improve|C++|Does not use XPath}}
The following code uses each of the three tasks given to demonstrate a different method of handling the resulting node set from an XPath query.
<lang cpp>#include <vector>

#include <string>
{{libheader|LibXML}}
<syntaxhighlight lang="cpp">#include <cassert>
#include <cstdlib>
#include <iostream>
#include <iostream>
#include <boost/regex.hpp>
#include <stdexcept>
#include <algorithm>
#include <utility>
#include <iterator>
#include <vector>


#include <libxml/parser.h>
int main( ) {
#include <libxml/tree.h>
const std::string xmltext(
#include <libxml/xmlerror.h>
"<inventory title=\"OmniCorp Store #45x10^3\">"
#include <libxml/xmlstring.h>
"<section name=\"health\">"
#include <libxml/xmlversion.h>
"<item upc=\"123456789\" stock=\"12\">"
#include <libxml/xpath.h>
"<name>Invisibility Cream</name>"

"<price>14.50</price>"
#ifndef LIBXML_XPATH_ENABLED
"<description>Makes you invisible</description>"
# error libxml was not configured with XPath support
"</item>"
#endif
"<item upc=\"445322344\" stock=\"18\">"

"<name>Levitation Salve</name>"
// Because libxml2 is a C library, we need a couple things to make it work
"<price>23.99</price>"
// well with modern C++:
"<description>Levitate yourself for up to 3 hours per application</description>"
// 1) a ScopeGuard-like type to handle cleanup functions; and
"</item>"
// 2) an exception type that transforms the library's errors.
"</section>"

"<section name=\"food\">"
// ScopeGuard-like type to handle C library cleanup functions.
"<item upc=\"485672034\" stock=\"653\">"
template <typename F>
"<name>Blork and Freen Instameal</name>"
class [[nodiscard]] scope_exit
"<price>4.95</price>"
{
"<description>A tasty meal in a tablet; just add water</description>"
public:
"</item>"
// C++20: Constructor can (and should) be [[nodiscard]].
"<item upc=\"132957764\" stock=\"44\">"
/*[[nodiscard]]*/ constexpr explicit scope_exit(F&& f) :
"<name>Grob winglets</name>"
f_{std::move(f)}
"<price>3.56</price>"
{}
"<description>Tender winglets of Grob. Just add water</description>"

"</item>"
~scope_exit()
"</section>"
{
"</inventory>" ) ;
f_();
std::string::size_type found = xmltext.find( "<item" , 0 ) ; //beginning of first item
}
std::string::size_type foundnext = xmltext.find( "</item>" , found + 5 ) ; //and its end

std::cout << "The first item is\n" << xmltext.substr( found + 5 , foundnext - ( found + 5 ) ) << '\n' ;
// Non-copyable, non-movable.
std::string::const_iterator start , end ;
scope_exit(scope_exit const&) = delete;
start = xmltext.begin( ) ;
scope_exit(scope_exit&&) = delete;
end = xmltext.end( ) ;
auto operator=(scope_exit const&) -> scope_exit& = delete;
boost::match_results<std::string::const_iterator> what ;
auto operator=(scope_exit&&) -> scope_exit& = delete;
boost::regex pricefind( "<price>(\\d+\\.?\\d+)</price>" ) ;//this regex finds the prices

start = xmltext.begin( ) ;
private:
std::cout << "The prices are:\n" ;
F f_;
while ( boost::regex_search( start , end , what , pricefind ) ) {
};
std::string price( what[ 1 ].first , what[ 1 ].second ) ;//find the first price

std::cout << price << std::endl ;
// Exception that gets last libxml2 error.
start = what[ 1 ].second ; //continue search after first price found
class libxml_error : public std::runtime_error
}
{
start = xmltext.begin( ) ;
public:
std::vector<std::string> names ;
libxml_error() : libxml_error(std::string{}) {}
boost::regex namefind( "<name>(.+?)</name>" ) ; //find characters, be greedy!

while ( boost::regex_search ( start , end , what , namefind ) ) {
std::string name ( what[ 1 ].first , what[ 1 ].second ) ;
explicit libxml_error(std::string message) :
std::runtime_error{make_message_(std::move(message))}
names.push_back( name ) ;
{}
start = what[ 1 ].second ;

}
private:
std::cout << "The following name elements were found in the xml string:\n" ;
std::copy( names.begin( ) , names.end( ) , std::ostream_iterator<std::string>( std::cout , "\n" )) ;
static auto make_message_(std::string message) -> std::string
return 0 ;
{
if (auto const last_error = ::xmlGetLastError(); last_error)
}</lang>
{
if (not message.empty())
message += ": ";
message += last_error->message;
}

return message;
}
};

auto main() -> int
{
try
{
// Initialize libxml.
::xmlInitParser();
LIBXML_TEST_VERSION
auto const libxml_cleanup = scope_exit{[] { ::xmlCleanupParser(); }};

// Load and parse XML document.
auto const doc = ::xmlParseFile("test.xml");
if (not doc)
throw libxml_error{"failed to load document"};
auto const doc_cleanup = scope_exit{[doc] { ::xmlFreeDoc(doc); }};

// Create XPath context for document.
auto const xpath_context = ::xmlXPathNewContext(doc);
if (not xpath_context)
throw libxml_error{"failed to create XPath context"};
auto const xpath_context_cleanup = scope_exit{[xpath_context]
{ ::xmlXPathFreeContext(xpath_context); }};

// Task 1 ============================================================
{
std::cout << "Task 1:\n";

auto const xpath =
reinterpret_cast<::xmlChar const*>(u8"//item[1]");

// Create XPath object (same for every task).
auto xpath_obj = ::xmlXPathEvalExpression(xpath, xpath_context);
if (not xpath_obj)
throw libxml_error{"failed to evaluate XPath"};
auto const xpath_obj_cleanup = scope_exit{[xpath_obj]
{ ::xmlXPathFreeObject(xpath_obj); }};

// 'result' a xmlNode* to the desired node, or nullptr if it
// doesn't exist. If not nullptr, the node is owned by 'doc'.
auto const result = xmlXPathNodeSetItem(xpath_obj->nodesetval, 0);
if (result)
std::cout << '\t' << "node found" << '\n';
else
std::cout << '\t' << "node not found" << '\n';
}

// Task 2 ============================================================
{
std::cout << "Task 2:\n";

auto const xpath =
reinterpret_cast<::xmlChar const*>(u8"//price/text()");

// Create XPath object (same for every task).
auto xpath_obj = ::xmlXPathEvalExpression(xpath, xpath_context);
if (not xpath_obj)
throw libxml_error{"failed to evaluate XPath"};
auto const xpath_obj_cleanup = scope_exit{[xpath_obj]
{ ::xmlXPathFreeObject(xpath_obj); }};

// Printing the results.
auto const count =
xmlXPathNodeSetGetLength(xpath_obj->nodesetval);
for (auto i = decltype(count){0}; i < count; ++i)
{
auto const node =
xmlXPathNodeSetItem(xpath_obj->nodesetval, i);
assert(node);

auto const content = XML_GET_CONTENT(node);
assert(content);

// Note that reinterpret_cast here is a Bad Idea, because
// 'content' is UTF-8 encoded, which may or may not be the
// encoding cout expects. A *PROPER* solution would translate
// content to the correct encoding (or at least verify that
// UTF-8 *is* the correct encoding).
//
// But this "works" well enough for illustration.
std::cout << "\n\t" << reinterpret_cast<char const*>(content);
}

std::cout << '\n';
}

// Task 3 ============================================================
{
std::cout << "Task 3:\n";

auto const xpath =
reinterpret_cast<::xmlChar const*>(u8"//name");

// Create XPath object (same for every task).
auto xpath_obj = ::xmlXPathEvalExpression(xpath, xpath_context);
if (not xpath_obj)
throw libxml_error{"failed to evaluate XPath"};
auto const xpath_obj_cleanup = scope_exit{[xpath_obj]
{ ::xmlXPathFreeObject(xpath_obj); }};

// 'results' is a vector of pointers to the result nodes. The
// nodes pointed to are owned by 'doc'.
auto const results = [ns=xpath_obj->nodesetval]()
{
auto v = std::vector<::xmlNode*>{};
if (ns && ns->nodeTab)
v.assign(ns->nodeTab, ns->nodeTab + ns->nodeNr);
return v;
}();
std::cout << '\t' << "set of " << results.size()
<< " node(s) found" << '\n';
}
}
catch (std::exception const& x)
{
std::cerr << "ERROR: " << x.what() << '\n';
return EXIT_FAILURE;
}
}
</syntaxhighlight>


=={{header|Caché ObjectScript}}==
=={{header|Caché ObjectScript}}==


<lang cos>Class XML.Inventory [ Abstract ]
<syntaxhighlight lang="cos">Class XML.Inventory [ Abstract ]
{
{


Line 319: Line 1,099:
}
}


}</lang>
}</syntaxhighlight>
{{out|Examples}}
{{out|Examples}}
<pre>
<pre>
Line 330: Line 1,110:
=={{header|CoffeeScript}}==
=={{header|CoffeeScript}}==
<div class='mw-collapsible mw-collapsed'>
<div class='mw-collapsible mw-collapsed'>
<lang coffeescript>
<syntaxhighlight lang="coffeescript">
doc = new DOMParser().parseFromString '
doc = new DOMParser().parseFromString '
<inventory title="OmniCorp Store #45x10^3">
<inventory title="OmniCorp Store #45x10^3">
Line 359: Line 1,139:
</inventory>
</inventory>
', 'text/xml'
', 'text/xml'
</syntaxhighlight>
</lang>
</div>
</div>
<nowiki>#</nowiki> "doc" is the XML as a Document object. Click expand to see parsing code ⇒
<nowiki>#</nowiki> "doc" is the XML as a Document object. Click expand to see parsing code ⇒


<lang coffeescript>
<syntaxhighlight lang="coffeescript">
# Retrieve the first "item" element
# Retrieve the first "item" element
doc.evaluate('//item', doc, {}, 7, {}).snapshotItem 0
doc.evaluate('//item', doc, {}, 7, {}).snapshotItem 0
Line 376: Line 1,156:
names = for i in [0...names.snapshotLength] by 1
names = for i in [0...names.snapshotLength] by 1
names.snapshotItem i
names.snapshotItem i
</syntaxhighlight>
</lang>


=={{header|ColdFusion}}==
=={{header|ColdFusion}}==
<lang cfm><cfsavecontent variable="xmlString">
<syntaxhighlight lang="cfm"><cfsavecontent variable="xmlString">
<inventory
<inventory
...
...
Line 399: Line 1,179:
<cfset names = xmlSearch(xml, "//name")>
<cfset names = xmlSearch(xml, "//name")>
<!--- visualize the results --->
<!--- visualize the results --->
<cfdump var="#variables#"></lang>
<cfdump var="#variables#"></syntaxhighlight>


=={{header|Common Lisp}}==
=={{header|Common Lisp}}==
Line 406: Line 1,186:
{{libheader|cxml-stp}}
{{libheader|cxml-stp}}


<lang lisp>(dolist (system '(:xpath :cxml-stp :cxml))
<syntaxhighlight lang="lisp">(dolist (system '(:xpath :cxml-stp :cxml))
(asdf:oos 'asdf:load-op system))
(asdf:oos 'asdf:load-op system))


Line 420: Line 1,200:


(node-array
(node-array
(xpath:evaluate "/inventory/section/item/name" *doc*))</lang>
(xpath:evaluate "/inventory/section/item/name" *doc*))</syntaxhighlight>


=={{header|D}}==
=={{header|D}}==
It is important to note that the KXML library currently only supports XPath minimally.
It is important to note that the KXML library currently only supports XPath minimally.
{{libheader|KXML}}
{{libheader|KXML}}
<lang d>import kxml.xml;
<syntaxhighlight lang="d">import kxml.xml;
char[]xmlinput =
char[]xmlinput =
"<inventory title=\"OmniCorp Store #45x10^3\">
"<inventory title=\"OmniCorp Store #45x10^3\">
Line 461: Line 1,241:
}
}
auto namearray = root.parseXPath("inventory/section/item/name");
auto namearray = root.parseXPath("inventory/section/item/name");
}</lang>
}</syntaxhighlight>


=={{header|Delphi}}==
=={{header|Delphi}}==
<lang Delphi>program XMLXPath;
<syntaxhighlight lang="delphi">program XMLXPath;


{$APPTYPE CONSOLE}
{$APPTYPE CONSOLE}
Line 528: Line 1,308:
for s in lItemNames do
for s in lItemNames do
Writeln('Item name = ' + s);
Writeln('Item name = ' + s);
end.</lang>
end.</syntaxhighlight>


Output:
Output:
<lang>First item node:
<syntaxhighlight lang="text">First item node:
<item upc="123456789" stock="12">
<item upc="123456789" stock="12">
<name>Invisibility Cream</name>
<name>Invisibility Cream</name>
Line 546: Line 1,326:
Item name = Levitation Salve
Item name = Levitation Salve
Item name = Blork and Freen Instameal
Item name = Blork and Freen Instameal
Item name = Grob winglets</lang>
Item name = Grob winglets</syntaxhighlight>


=={{header|E}}==
=={{header|E}}==
Line 552: Line 1,332:
{{libheader|E-XML}} (currently a very early work in progress/draft library; design comments welcome)
{{libheader|E-XML}} (currently a very early work in progress/draft library; design comments welcome)


<lang e>? def xml__quasiParser := <import:org.switchb.e.xml.makeXMLQuasiParser>()
<syntaxhighlight lang="e">? def xml__quasiParser := <import:org.switchb.e.xml.makeXMLQuasiParser>()
> def xpath__quasiParser := xml__quasiParser.xPathQuasiParser()
> def xpath__quasiParser := xml__quasiParser.xPathQuasiParser()
> null
> null
Line 602: Line 1,382:
# xml`<name>Blork and Freen Instameal</name>`,
# xml`<name>Blork and Freen Instameal</name>`,
# xml`<name>Grob winglets</name>`]
# xml`<name>Grob winglets</name>`]
</syntaxhighlight>
</lang>


=={{header|Erlang}}==
=={{header|Erlang}}==
Line 608: Line 1,388:
{{libheader|xmerl}}
{{libheader|xmerl}}


<lang erlang>
<syntaxhighlight lang="erlang">
-module(xml_xpath).
-module(xml_xpath).
-include_lib("xmerl/include/xmerl.hrl").
-include_lib("xmerl/include/xmerl.hrl").
Line 657: Line 1,437:
[ Content#xmlText.value
[ Content#xmlText.value
|| #xmlElement{content = [Content|_]} <- xmerl_xpath:string("//name", Document)].
|| #xmlElement{content = [Content|_]} <- xmerl_xpath:string("//name", Document)].
</syntaxhighlight>
</lang>


Output:<pre>First item:
Output:<pre>First item:
Line 674: Line 1,454:
"Blork and Freen Instameal","Grob winglets"]
"Blork and Freen Instameal","Grob winglets"]
</pre>
</pre>

=={{header|FreeBASIC}}==
<syntaxhighlight lang="vbnet">Dim As String XML, item, price, nombre
Dim As Integer P1, P2

'' Read the XML file
Open "test3.xml" For Input As #1
XML = Input(Lof(1), #1)
Close #1

'' Find the first 'item' element
P1 = Instr(XML, "<item ")
P2 = Instr(XML, "</item>")
item = Mid(XML, P1, P2-P1+7)
Print "The first 'item' element is:"
Print item

'' Find all 'price' elements
Print "The 'prices' are:"
P1 = 1
Do
P1 = Instr(P1, XML, "<price>")
If P1 = 0 Then Exit Do
P2 = Instr(P1, XML, "</price>")
price = Mid(XML, P1+7, P2-P1-7)
Print price
P1 = P2 + 1
Loop

'' Find all 'nombre' elements
Print !"\nThe 'names' are:"
P1 = 1
Do
P1 = Instr(P1, XML, "<name>")
If P1 = 0 Then Exit Do
P2 = Instr(P1, XML, "</name>")
nombre = Mid(XML, P1+6, P2-P1-6)
Print nombre
P1 = P2 + 1
Loop

Sleep</syntaxhighlight>


=={{header|F_Sharp|F#}}==
=={{header|F_Sharp|F#}}==
<lang fsharp>
<syntaxhighlight lang="fsharp">
open System.IO
open System.IO
open System.Xml.XPath
open System.Xml.XPath
Line 719: Line 1,541:


// array of all name elements
// array of all name elements
let names = seq { for name in nav.Select(@"//name") do yield name } |> Seq.toArray</lang>
let names = seq { for name in nav.Select(@"//name") do yield name } |> Seq.toArray</syntaxhighlight>


=={{header|Factor}}==
=={{header|Factor}}==
Line 726: Line 1,548:
{{libheader|xml.traversal}}
{{libheader|xml.traversal}}


<lang factor>
<syntaxhighlight lang="factor">


! Get first item element
! Get first item element
Line 811: Line 1,633:
</section>
</section>
</inventory>""" string>xml "name" deep-tags-named
</inventory>""" string>xml "name" deep-tags-named
</syntaxhighlight>
</lang>

=={{header|Gastona}}==
The example uses the command XMELON which parses a XML file of any schema and stores its
contents into db tables. This parser is described in the article [http://web3.codeproject.com/Articles/680642/XMeLon-Schema XMeLon-Schema]
<syntaxhighlight lang="gastona">#javaj#

<frames> oSal, XML Path sample, 300, 400
#data#

<xml>
//<inventory title="OmniCorp Store #45x10^3">
// <section name="health">
// <item upc="123456789" stock="12">
// <name>Invisibility Cream</name>
// <price>14.50</price>
// <description>Makes you invisible</description>
// </item>
// <item upc="445322344" stock="18">
// <name>Levitation Salve</name>
// <price>23.99</price>
// <description>Levitate yourself for up to 3 hours per application</description>
// </item>
// </section>
// <section name="food">
// <item upc="485672034" stock="653">
// <name>Blork and Freen Instameal</name>
// <price>4.95</price>
// <description>A tasty meal in a tablet; just add water</description>
// </item>
// <item upc="132957764" stock="44">
// <name>Grob winglets</name>
// <price>3.56</price>
// <description>Tender winglets of Grob. Just add water</description>
// </item>
// </section>
//</inventory>
<DEEP_SQL_XML>
DEEP DB, SELECT, xmelon_data
,, path pathStr
,, tag tagStr
,, patCnt
,, dataPlace
,, value
#listix#

<main>
//parsing xml data ...
GEN, :mem datos, xml
XMELON, FILE2DB, :mem datos
//
//first item ...
//
//
LOOP, SQL,, //SELECT patCnt AS patITEM1 FROM (@<DEEP_SQL_XML>) WHERE path_pathStr == '/inventory/section/item' LIMIT 1
,HEAD, //<item
,, LOOP, SQL,, //SELECT * FROM (@<DEEP_SQL_XML>) WHERE patCnt == @<patITEM1> AND dataPlace == 'A'
,, , LINK, ""
,, ,, // @<tag_tagStr>="@<value>"
,, //>
,, //
,, LOOP, SQL,, //SELECT * FROM (@<DEEP_SQL_XML>) WHERE patCnt == @<patITEM1> AND dataPlace != 'A'
,, ,, // <@<tag_tagStr>>@<value></@<tag_tagStr>>
,TAIL, //
,TAIL, //</item>
//
//
//report prices ...
//
LOOP, SQL,, //SELECT value FROM (@<DEEP_SQL_XML>) WHERE tag_tagStr == 'price'
, LINK, ", "
,, @<value>
//
//put names into a variable
//
VAR=, tabnames, "name"
LOOP, SQL,, //SELECT value FROM (@<DEEP_SQL_XML>) WHERE tag_tagStr == 'name'
, LINK, ""
,, VAR+, tabnames, @<value>
DUMP, data,, tabnames
</syntaxhighlight>

{{out|Output}}
<pre>
parsing xml data ...
first item ...

<item upc="123456789" stock="12">
<name>Invisibility Cream</name>
<price>14.50</price>
<description>Makes you invisible</description>
</item>

report prices ...
14.50, 23.99, 4.95, 3.56
names into a variable
#data#

<tabnames>
//name
//health
//Invisibility Cream
//Levitation Salve
//food
//Blork and Freen Instameal
//Grob winglets
</pre>


=={{header|Go}}==
=={{header|Go}}==
Using the standard <code>encoding/xml</code> package:
Using the standard <code>encoding/xml</code> package:
<lang go>package main
<syntaxhighlight lang="go">package main


import (
import (
Line 894: Line 1,825:
}
}
fmt.Printf("names: %q\n", names)
fmt.Printf("names: %q\n", names)
}</lang>
}</syntaxhighlight>
{{out}}
{{out}}
<pre>
<pre>
Line 917: Line 1,848:


{{libheader|xmlpath}}
{{libheader|xmlpath}}
<lang go>package main
<syntaxhighlight lang="go">package main


import (
import (
Line 954: Line 1,885:
fmt.Println("no names")
fmt.Println("no names")
}
}
}</lang>
}</syntaxhighlight>
{{out}}
{{out}}
<pre>
<pre>
Line 964: Line 1,895:


=={{header|Groovy}}==
=={{header|Groovy}}==
<lang groovy>def inventory = new XmlSlurper().parseText("<inventory...") //optionally parseText(new File("inv.xml").text)
<syntaxhighlight lang="groovy">def inventory = new XmlSlurper().parseText("<inventory...") //optionally parseText(new File("inv.xml").text)
def firstItem = inventory.section.item[0] //1. first item
def firstItem = inventory.section.item[0] //1. first item
inventory.section.item.price.each { println it } //2. print each price
inventory.section.item.price.each { println it } //2. print each price
def allNamesArray = inventory.section.item.name.collect {it} //3. collect item names into an array</lang>
def allNamesArray = inventory.section.item.name.collect {it} //3. collect item names into an array</syntaxhighlight>


=={{header|Haskell}}==
=={{header|Haskell}}==
<lang haskell>import Data.List
<syntaxhighlight lang="haskell">import Data.List
import Control.Arrow
import Control.Arrow
import Control.Monad
import Control.Monad
Line 994: Line 1,925:
putStrLn "\n== Names ==\n"
putStrLn "\n== Names ==\n"
print $ getsingleLineItems "name" xmlText</lang>
print $ getsingleLineItems "name" xmlText</syntaxhighlight>
Using the Haskell XML Toolkit (HXT):
Using the Haskell XML Toolkit (HXT):
<lang haskell>{-# LANGUAGE Arrows #-}
<syntaxhighlight lang="haskell">{-# LANGUAGE Arrows #-}
import Text.XML.HXT.Arrow
import Text.XML.HXT.Arrow
{- For HXT version >= 9.0, use instead:
{- For HXT version >= 9.0, use instead:
Line 1,013: Line 1,944:
[(item, names)] <- runX (readDocument [] "xmlpath.xml" >>> process)
[(item, names)] <- runX (readDocument [] "xmlpath.xml" >>> process)
print item
print item
print names</lang>
print names</syntaxhighlight>


=={{header|HicEst}}==
=={{header|HicEst}}==
<lang hicest>CHARACTER xml*1000, output*1000
<syntaxhighlight lang="hicest">CHARACTER xml*1000, output*1000
READ(ClipBoard) xml
READ(ClipBoard) xml


Line 1,030: Line 1,961:


EDIT(Text=xml, SPR='<>', R='<name>', W=1, WordEnd=$CR, APpendTo=output, DO=999)
EDIT(Text=xml, SPR='<>', R='<name>', W=1, WordEnd=$CR, APpendTo=output, DO=999)
WRITE(ClipBoard) TRIM(output) </lang>
WRITE(ClipBoard) TRIM(output) </syntaxhighlight>
<lang hicest> upc="123456789" stock="12">
<syntaxhighlight lang="hicest"> upc="123456789" stock="12">
<name>Invisibility Cream</name>
<name>Invisibility Cream</name>
<price>14.50</price>
<price>14.50</price>
Line 1,044: Line 1,975:
Blork and Freen Instameal
Blork and Freen Instameal
Grob winglets
Grob winglets
</syntaxhighlight>
</lang>


=={{header|Java}}==
=={{header|Java}}==
<lang java>import java.io.StringReader;
<syntaxhighlight lang="java">import java.io.StringReader;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPath;
Line 1,106: Line 2,037:
}
}
}
}
}</lang>
}</syntaxhighlight>

=={{header|JavaScript}}==
=={{header|JavaScript}}==
{{works with|Firefox|2.0}}
{{works with|Firefox|2.0}}
<lang javascript>//create XMLDocument object from file
<syntaxhighlight lang="javascript">//create XMLDocument object from file
var xhr = new XMLHttpRequest();
var xhr = new XMLHttpRequest();
xhr.open('GET', 'file.xml', false);
xhr.open('GET', 'file.xml', false);
Line 1,131: Line 2,063:
namesArray.push( name );
namesArray.push( name );
}
}
alert( namesArray );</lang>
alert( namesArray );</syntaxhighlight>


Although some browsers support XPath, working with XML is much easier with E4X.
Although some browsers support XPath, working with XML is much easier with E4X.


<lang javascript>//create XML object from file
<syntaxhighlight lang="javascript">//create XML object from file
var xhr = new XMLHttpRequest();
var xhr = new XMLHttpRequest();
xhr.open('GET', 'file.xml', false);
xhr.open('GET', 'file.xml', false);
Line 1,155: Line 2,087:
names.push( name );
names.push( name );
}
}
alert( names );</lang>
alert( names );</syntaxhighlight>


=={{header|Julia}}==
Uses the LibExpat module for XML pathing. The exercise description is very
vague about output format, so this is varied in the solution below. The first
test prints the raw XML node, and the second and third are further processed.
<syntaxhighlight lang="julia">using LibExpat

xdoc = raw"""<inventory title="OmniCorp Store #45x10^3">
<section name="health">
<item upc="123456789" stock="12">
<name>Invisibility Cream</name>
<price>14.50</price>
<description>Makes you invisible</description>
</item>
<item upc="445322344" stock="18">
<name>Levitation Salve</name>
<price>23.99</price>
<description>Levitate yourself for up to 3 hours per application</description>
</item>
</section>
<section name="food">
<item upc="485672034" stock="653">
<name>Blork and Freen Instameal</name>
<price>4.95</price>
<description>A tasty meal in a tablet; just add water</description>
</item>
<item upc="132957764" stock="44">
<name>Grob winglets</name>
<price>3.56</price>
<description>Tender winglets of Grob. Just add water</description>
</item>
</section>
</inventory>
"""

debracket(s) = replace(s, r".+\>(.+)\<.+" => s"\1")

etree = xp_parse(xdoc)
firstshow = LibExpat.find(etree, "//item")[1]
println("The first item's node XML entry is:\n", firstshow, "\n\n")

prices = LibExpat.find(etree, "//price")
println("Prices:")
for p in prices
println("\t", debracket(string(p)))
end
println("\n")

namearray = LibExpat.find(etree, "//name")
println("Array of names of items:\n\t", map(s -> debracket(string(s)), namearray))
</syntaxhighlight>{{output}}<pre>
The first item's node XML entry is:
<item upc="123456789" stock="12">
<name>Invisibility Cream</name>
<price>14.50</price>
<description>Makes you invisible</description>
</item>


Prices:
14.50
23.99
4.95
3.56


Array of names of items:
["Invisibility Cream", "Levitation Salve", "Blork and Freen Instameal", "Grob winglets"]
</pre>

=={{header|Kotlin}}==
<syntaxhighlight lang="scala">// version 1.1.3

import javax.xml.parsers.DocumentBuilderFactory
import org.xml.sax.InputSource
import java.io.StringReader
import javax.xml.xpath.XPathFactory
import javax.xml.xpath.XPathConstants
import org.w3c.dom.Node
import org.w3c.dom.NodeList

val xml =
"""
<inventory title="OmniCorp Store #45x10^3">
<section name="health">
<item upc="123456789" stock="12">
<name>Invisibility Cream</name>
<price>14.50</price>
<description>Makes you invisible</description>
</item>
<item upc="445322344" stock="18">
<name>Levitation Salve</name>
<price>23.99</price>
<description>Levitate yourself for up to 3 hours per application</description>
</item>
</section>
<section name="food">
<item upc="485672034" stock="653">
<name>Blork and Freen Instameal</name>
<price>4.95</price>
<description>A tasty meal in a tablet; just add water</description>
</item>
<item upc="132957764" stock="44">
<name>Grob winglets</name>
<price>3.56</price>
<description>Tender winglets of Grob. Just add water</description>
</item>
</section>
</inventory>
"""

fun main(args: Array<String>) {
val dbFactory = DocumentBuilderFactory.newInstance()
val dBuilder = dbFactory.newDocumentBuilder()
val xmlInput = InputSource(StringReader(xml))
val doc = dBuilder.parse(xmlInput)
val xpFactory = XPathFactory.newInstance()
val xPath = xpFactory.newXPath()

val qNode = xPath.evaluate("/inventory/section/item[1]", doc, XPathConstants.NODE) as Node
val upc = qNode.attributes.getNamedItem("upc")
val stock = qNode.attributes.getNamedItem("stock")
println("For the first item : upc = ${upc.textContent} and stock = ${stock.textContent}")

val qNodes = xPath.evaluate("/inventory/section/item/price", doc, XPathConstants.NODESET) as NodeList
print("\nThe prices of each item are : ")
for (i in 0 until qNodes.length) print("${qNodes.item(i).textContent} ")
println()

val qNodes2 = xPath.evaluate("/inventory/section/item/name", doc, XPathConstants.NODESET) as NodeList
val names = Array<String>(qNodes2.length) { qNodes2.item(it).textContent }
println("\nThe names of each item are as follows :")
println(" ${names.joinToString("\n ")}")
}</syntaxhighlight>

{{out}}
<pre>
For the first item : upc = 123456789 and stock = 12

The prices of each item are : 14.50 23.99 4.95 3.56

The names of each item are as follows :
Invisibility Cream
Levitation Salve
Blork and Freen Instameal
Grob winglets
</pre>

=={{header|Ksh}}==
<syntaxhighlight lang="ksh">
#!/bin/ksh

# Perform XPath queries on a XML Document

# # Variables:
#
typeset -T Xml_t=(
typeset -h 'UPC' upc
typeset -i -h 'num in stock' stock=0
typeset -h 'name' name
typeset -F2 -h 'price' price
typeset -h 'description' description

function init_item {
typeset key ; key="$1"
typeset val ; val="${2%\<\/${key}*}"

case ${key} in
upc) _.upc="${val//@(\D)/}"
;;
stock) _.stock="${val//@(\D)/}"
;;
name) _.name="${val%\<\/${key}*}"
;;
price) _.price="${val}"
;;
description) _.description=$(echo ${val})
;;
esac
}

function prt_item {
print "upc= ${_.upc}"
print "stock= ${_.stock}"
print "name= ${_.name}"
print "price= ${_.price}"
print "description= ${_.description}"
}
)

# # Functions:
#


######
# main #
######
integer i=0
typeset -a Item_t

buff=$(< xmldoc) # read xmldoc
item=${buff%%'</item>'*} ; buff=${.sh.match}

while [[ -n ${item} ]]; do
Xml_t Item_t[i]
item=${item#*'<item'} ; item=$(echo ${item})
for word in ${item}; do
if [[ ${word} == *=* ]]; then
Item_t[i].init_item ${word%\=*} ${word#*\=}
else
if [[ ${word} == \<* ]]; then # Beginning
key=${word%%\>*} ; key=${key#*\<}
val=${word#*\>}
fi

[[ ${word} != \<* && ${word} != *\> ]] && val+=" ${word} "

if [[ ${word} == *\> ]]; then # End
val+=" ${word%\<${key}\>*}"
Item_t[i].init_item "${key}" "${val}"
fi
fi
done
(( i++ ))
item=${buff#*'</item>'} ; item=${item%%'</item>'*} ; buff=${.sh.match}
done

print "First Item element:"
Item_t[0].prt_item

typeset -a names
printf "\nList of prices:\n"
for ((i=0; i<${#Item_t[*]}-1; i++)); do
print ${Item_t[i].price}
names[i]=${Item_t[i].name}
done

printf "\nArray of names:\n"
for (( i=0; i<${#names[*]}; i++)); do
print "names[$i] = ${names[i]}"
done</syntaxhighlight>
{{out}}<pre>
First Item element:
upc= 123456789
stock= 12
name= Invisibility Cream
price= 14.50
description= Makes you invisible

List of prices:
14.50
23.99
4.95
3.56

Array of names:
names[0] = Invisibility Cream
names[1] = Levitation Salve
names[2] = Blork and Freen Instameal
names[3] = Grob winglets</pre>


=={{header|Lasso}}==
=={{header|Lasso}}==
Lasso has built in support for both XML handling and Xpaths
Lasso has built in support for both XML handling and Xpaths
<lang Lasso>// makes extracting attribute values easier
<syntaxhighlight lang="lasso">// makes extracting attribute values easier
define xml_attrmap(in::xml_namedNodeMap_attr) => {
define xml_attrmap(in::xml_namedNodeMap_attr) => {
local(out = map)
local(out = map)
Line 1,229: Line 2,420:
'<br /><br />'
'<br /><br />'
'<strong>Array with all names:</strong><br />'
'<strong>Array with all names:</strong><br />'
#xml -> extract('//name') -> asstaticarray</lang>
#xml -> extract('//name') -> asstaticarray</syntaxhighlight>
Output:
Output:
<pre>First item:
<pre>First item:
Line 1,243: Line 2,434:
Array with all names:
Array with all names:
staticarray(Invisibility Cream, Levitation Salve, Blork and Freen Instameal, Grob winglets)</pre>
staticarray(Invisibility Cream, Levitation Salve, Blork and Freen Instameal, Grob winglets)</pre>

=={{header|LiveCode}}==
Copy the xml in this task into a text field called "FieldXML"
<syntaxhighlight lang="livecode">put revXMLCreateTree(fld "FieldXML",true,true,false) into xmltree

// task 1
put revXMLEvaluateXPath(xmltree,"//item[1]") into nodepath
put revXMLText(xmltree,nodepath,true)

// task 2
put revXMLDataFromXPathQuery(xmltree,"//item/price",,comma)

// task 3
put revXMLDataFromXPathQuery(xmltree,"//name") into namenodes
filter namenodes without empty
split namenodes using cr
put namenodes is an array</syntaxhighlight>


=={{header|Lua}}==
=={{header|Lua}}==
Requires LuaExpat
Requires LuaExpat
<lang lua>require 'lxp'
<syntaxhighlight lang="lua">require 'lxp'
data = [[<inventory title="OmniCorp Store #45x10^3">
data = [[<inventory title="OmniCorp Store #45x10^3">
<section name="health">
<section name="health">
Line 1,289: Line 2,497:


print('Name: ', table.concat(names, ', '))
print('Name: ', table.concat(names, ', '))
print('Price: ', table.concat(prices, ', '))</lang>
print('Price: ', table.concat(prices, ', '))</syntaxhighlight>
Output:<pre>
Output:<pre>
<item upc="123456789" stock="12">
<item upc="123456789" stock="12">
Line 1,300: Line 2,508:
</pre>
</pre>


=={{header|Mathematica}}==
=={{header|Mathematica}}/{{header|Wolfram Language}}==
<lang Mathematica>example = Import["test.txt", "XML"];
<syntaxhighlight lang="mathematica">example = Import["test.txt", "XML"];
Cases[example, XMLElement["item", _ , _] , Infinity] // First
Cases[example, XMLElement["item", _ , _] , Infinity] // First
Cases[example, XMLElement["price", _, List[n_]] -> n, Infinity] // Column
Cases[example, XMLElement["price", _, List[n_]] -> n, Infinity] // Column
Cases[example, XMLElement["name", _, List[n_]] -> n, Infinity] // Column</lang>
Cases[example, XMLElement["name", _, List[n_]] -> n, Infinity] // Column</syntaxhighlight>
{{out}}
Output:<pre>
XMLElement[item,{upc->123456789,stock->12},
<pre>XMLElement[item,{upc->123456789,stock->12},
{XMLElement[name,{},{Invisibility Cream}],XMLElement[price,{},{14.50}],XMLElement[description,{},{Makes you invisible}]}]
{XMLElement[name,{},{Invisibility Cream}],XMLElement[price,{},{14.50}],XMLElement[description,{},{Makes you invisible}]}]

14.50
14.50
23.99
23.99
4.95
4.95
3.56
3.56

Invisibility Cream
Invisibility Cream
Levitation Salve
Levitation Salve
Blork and Freen Instameal
Blork and Freen Instameal
Grob winglets
Grob winglets</pre>
</pre>


=={{header|NetRexx}}==
=={{header|NetRexx}}==
{{trans|Java}}
{{trans|Java}}
<lang NetRexx>/* NetRexx */
<syntaxhighlight lang="netrexx">/* NetRexx */
options replace format comments java crossref symbols binary
options replace format comments java symbols binary


import javax.xml.parsers.
import javax.xml.parsers.
import javax.xml.xpath.
import javax.xml.xpath.
import org.w3c.dom.
import org.w3c.dom.
import org.w3c.dom.Node
import org.xml.sax.
import org.xml.sax.


Line 1,400: Line 2,606:


return
return
</syntaxhighlight>
</lang>
'''Output:'''
'''Output:'''
<pre>
<pre>
Line 1,420: Line 2,626:


=={{header|Nim}}==
=={{header|Nim}}==
{{libheader|libxml2}}
<lang nim>import xmldom, xmldomparser
Nim standard library provides several modules to process XML, but none to process XPath requests. There is no third party library to do that either.


So we provide here a solution which uses the C "libxml2" library. Nim allows to interface with C with a great flexibility. Declaring the external functions is quite easy. The major part of the work consists to declare the data types. In "libxml2" there are a lot of structures and we have translated only what is needed to solve the task (or actually a bit more).
let doc = "test3.xml".loadXMLFile.documentElement


For the first request, we use <code>//section[1]/item[1]</code> instead of <code>//item[1]</code> (this is also what the Python version does). The latter request works but it returns the first element in each section which doesn’t seem to be what is expected.
# 1st task: retrieve the first "item" element
let i = doc.getElementsByTagName("item")[0]


<syntaxhighlight lang="nim">import sequtils, strutils
# 2nd task: perform an action on each "price" element (print it out)

for j in doc.getElementsByTagName "price":
const LibXml = "libxml2.so"
echo j.firstChild.PText.data

type

XmlDocPtr = pointer

XmlXPathContextPtr = pointer

XmlElementKind = enum
xmlElementNode = 1
xmlAttributeNode = 2
xmlTextNode = 3
xmlCdataSectionNode = 4
xmlEntityRefNode = 5
xmlEntityNode = 6
xmlPiNode = 7
xmlCommentNode = 8
xmlDocumentNode = 9
xmlDocumentTypeNode = 10
xmlDocumentFragNode = 11
xmlNotationNode = 12
xmlHtmlDocumentNode = 13
xmlDtdNode = 14
xmlElementDecl = 15
xmlAttributeDecl = 16
xmlEntityDecl = 17
xmlNamespaceDecl = 18
xmlXincludeStart = 19
xmlXincludeEnd = 20

XmlNsKind = XmlElementKind

XmlNsPtr = ptr XmlNs
XmlNs = object
next: XmlNsPtr
kind: XmlNsKind
href: cstring
prefix: cstring
private: pointer
context: XmlDocPtr

XmlAttrPtr = pointer

XmlNodePtr = ptr XmlNode
XmlNode = object
private: pointer
kind: XmlElementKind
name: cstring
children: XmlNodePtr
last: XmlNodePtr
parent: XmlNodePtr
next: XmlNodePtr
prev: XmlNodePtr
doc: XmlDocPtr
ns: XmlNsPtr
content: cstring
properties: XmlAttrPtr
nsDef: XmlNsPtr
psvi: pointer
line: cushort
extra: cushort

XmlNodeSetPtr = ptr XmlNodeSet
XmlNodeSet = object
nodeNr: cint
nodeMax: cint
nodeTab: ptr UncheckedArray[XmlNodePtr]

XmlPathObjectKind = enum
xpathUndefined
xpathNodeset
xpathBoolean
xpathNumber
xpathString
xpathPoint
xpathRange
xpathLocationset
xpathUsers
xpathXsltTree

XmlXPathObjectPtr = ptr XmlXPathObject
XmlXPathObject = object
kind: XmlPathObjectKind
nodeSetVal: XmlNodeSetPtr
boolVal: cint
floatVal: cdouble
stringVal: cstring
user: pointer
index: cint
user2: pointer
index2: cint

XmlSaveCtxtPtr = pointer

XmlBufferPtr = pointer


# Declaration of needed "libxml2" procedures.
proc xmlParseFile(docName: cstring): XmlDocPtr
{.cdecl, dynlib: LibXml, importc: "xmlParseFile".}

proc xmlXPathNewContext(doc: XmlDocPtr): XmlXPathContextPtr
{.cdecl, dynlib: LibXml, importc: "xmlXPathNewContext".}

proc xmlXPathEvalExpression(str: cstring; ctxt: XmlXPathContextPtr): XmlXPathObjectPtr
{.cdecl, dynlib: LibXml, importc: "xmlXPathEvalExpression".}

proc xmlXPathFreeContext(ctxt: XmlXPathContextPtr)
{.cdecl, dynlib: LibXml, importc: "xmlXPathFreeContext".}

proc xmlXPathFreeObject(obj: XmlXPathObjectPtr)
{.cdecl, dynlib: LibXml, importc: "xmlXPathFreeObject".}

proc xmlSaveToBuffer(vuffer: XmlBufferPtr; encoding: cstring; options: cint): XmlSaveCtxtPtr
{.cdecl, dynlib: LibXml, importc: "xmlSaveToBuffer".}

proc xmlBufferCreate(): XmlBufferPtr
{.cdecl, dynlib: LibXml, importc: "xmlBufferCreate".}

proc xmlBufferFree(buf: XmlBufferPtr)
{.cdecl, dynlib: LibXml, importc: "xmlBufferCreate".}

proc xmlBufferContent(buf: XmlBufferPtr): cstring
{.cdecl, dynlib: LibXml, importc: "xmlBufferContent".}

proc xmlSaveTree(ctxt: XmlSaveCtxtPtr; cur: XmlNodePtr): clong
{.cdecl, dynlib: LibXml, importc: "xmlSaveTree".}

proc xmlSaveClose(ctxt: XmlSaveCtxtPtr)
{.cdecl, dynlib: LibXml, importc: "xmlSaveClose".}


proc `$`(node: XmlNodePtr): string =
## Return the representation of a node.
let buffer = xmlBufferCreate()
let saveContext = xmlSaveToBuffer(buffer, nil, 0)
discard saveContext.xmlSaveTree(node)
saveContext.xmlSaveClose()
result = $buffer.xmlBufferContent()
xmlBufferFree(buffer)


iterator nodes(xpath: string; context: XmlXPathContextPtr): XmlNodePtr =
## Yield the nodes which fit the XPath request.
let xpathObj = xmlXPathEvalExpression(xpath, context)
if xpathObj.isNil:
quit "Failed to evaluate XPath: " & xpath, QuitFailure
assert xpathObj.kind == xpathNodeset
let nodeSet = xpathObj.nodeSetVal
if not nodeSet.isNil:
for i in 0..<nodeSet.nodeNr:
yield nodeSet.nodeTab[i]
xmlXPathFreeObject(xpathObj)


# Load and parse XML file.
let doc = xmlParseFile("xpath_test.xml")
if doc.isNil:
quit "Unable to load and parse document", QuitFailure

# Create an XPath context.
let context = xmlXPathNewContext(doc)
if context.isNil:
quit "Failed to create XPath context", QuitFailure

var xpath = "//section[1]/item[1]"
echo "Request $#:".format(xpath)
for node in nodes(xpath, context):
echo node
echo()

xpath = "//price/text()"
echo "Request $#:".format(xpath)
for node in nodes(xpath, context):
echo node.content
echo()

xpath = "//name"
echo "Request $#:".format(xpath)
let names = toSeq(nodes(xpath, context)).mapIt(it.children.content)
echo names

xmlXPathFreeContext(context)</syntaxhighlight>

{{out}}
<pre>Request //section[1]/item[1]:
<item upc="123456789" stock="12">
<name>Invisibility Cream</name>
<price>14.50</price>
<description>Makes you invisible</description>
</item>

Request //price/text():
14.50
23.99
4.95
3.56


Request //name:
# 3rd task: get an array of all the "name" elements
@["Invisibility Cream", "Levitation Salve", "Blork and Freen Instameal", "Grob winglets"]</pre>
let namesArray = doc.getElementsByTagName "name"</lang>


=={{header|Objeck}}==
=={{header|Objeck}}==
XPath is used to fetch element tags.
XPath is used to fetch element tags.
<lang objeck>
<syntaxhighlight lang="objeck">
use XML;
use XML;


Line 1,494: Line 2,896:
}
}
}
}
</syntaxhighlight>
</lang>


=={{header|Oz}}==
=={{header|Oz}}==
We implement a small subset of XPath for this task:
We implement a small subset of XPath for this task:
<lang oz>declare
<syntaxhighlight lang="oz">declare
[XMLParser] = {Module.link ['x-oz://system/xml/Parser.ozf']}
[XMLParser] = {Module.link ['x-oz://system/xml/Parser.ozf']}


Line 1,584: Line 2,986:
#"</inventory>"
#"</inventory>"
in
in
{Main Data}</lang>
{Main Data}</syntaxhighlight>


=={{header|Perl}}==
=={{header|Perl}}==
{{libheader|XML::XPath}}
{{libheader|XML::XPath}}
<lang perl>use XML::XPath qw();
<syntaxhighlight lang="perl">use XML::XPath qw();


my $x = XML::XPath->new('<inventory ... </inventory>');
my $x = XML::XPath->new('<inventory ... </inventory>');
Line 1,594: Line 2,996:
[$x->findnodes('//item[1]')->get_nodelist]->[0];
[$x->findnodes('//item[1]')->get_nodelist]->[0];
print $x->findnodes_as_string('//price');
print $x->findnodes_as_string('//price');
$x->findnodes('//name')->get_nodelist;</lang>
$x->findnodes('//name')->get_nodelist;</syntaxhighlight>

=={{header|Phix}}==
Phix has no direct support for XPath, but achieving the requirements using the standard xml_parse() is not exactly difficult.
<!--<syntaxhighlight lang="phix">(phixonline)-->
<span style="color: #008080;">include</span> <span style="color: #000000;">builtins</span><span style="color: #0000FF;">/</span><span style="color: #000000;">xml</span><span style="color: #0000FF;">.</span><span style="color: #000000;">e</span>
<span style="color: #008080;">constant</span> <span style="color: #000000;">xml_txt</span> <span style="color: #0000FF;">=</span> <span style="color: #008000;">"""
&lt;inventory title="OmniCorp Store #45x10^3"&gt;
&lt;section name="health"&gt;
&lt;item upc="123456789" stock="12"&gt;
&lt;name&gt;Invisibility Cream&lt;/name&gt;
&lt;price&gt;14.50&lt;/price&gt;
&lt;description&gt;Makes you invisible&lt;/description&gt;
&lt;/item&gt;
&lt;item upc="445322344" stock="18"&gt;
&lt;name&gt;Levitation Salve&lt;/name&gt;
&lt;price&gt;23.99&lt;/price&gt;
&lt;description&gt;Levitate yourself for up to 3 hours per application&lt;/description&gt;
&lt;/item&gt;
&lt;/section&gt;
&lt;section name="food"&gt;
&lt;item upc="485672034" stock="653"&gt;
&lt;name&gt;Blork and Freen Instameal&lt;/name&gt;
&lt;price&gt;4.95&lt;/price&gt;
&lt;description&gt;A tasty meal in a tablet; just add water&lt;/description&gt;
&lt;/item&gt;
&lt;item upc="132957764" stock="44"&gt;
&lt;name&gt;Grob winglets&lt;/name&gt;
&lt;price&gt;3.56&lt;/price&gt;
&lt;description&gt;Tender winglets of Grob. Just add water&lt;/description&gt;
&lt;/item&gt;
&lt;/section&gt;
&lt;/inventory&gt;
"""</span><span style="color: #0000FF;">,</span>
<span style="color: #000080;font-style:italic;">-- or, of course, xml_txt = get_text("input.xml")</span>
<span style="color: #000000;">xml</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">xml_parse</span><span style="color: #0000FF;">(</span><span style="color: #000000;">xml_txt</span><span style="color: #0000FF;">)</span>
<span style="color: #004080;">sequence</span> <span style="color: #000000;">sections</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">xml_get_nodes</span><span style="color: #0000FF;">(</span><span style="color: #000000;">xml</span><span style="color: #0000FF;">[</span><span style="color: #000000;">XML_CONTENTS</span><span style="color: #0000FF;">],</span><span style="color: #008000;">"section"</span><span style="color: #0000FF;">),</span>
<span style="color: #000000;">item1</span> <span style="color: #0000FF;">=</span> <span style="color: #0000FF;">{},</span>
<span style="color: #000000;">prices</span> <span style="color: #0000FF;">=</span> <span style="color: #0000FF;">{},</span>
<span style="color: #000000;">names</span> <span style="color: #0000FF;">=</span> <span style="color: #0000FF;">{}</span>
<span style="color: #008080;">for</span> <span style="color: #000000;">s</span><span style="color: #0000FF;">=</span><span style="color: #000000;">1</span> <span style="color: #008080;">to</span> <span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">sections</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">do</span>
<span style="color: #004080;">sequence</span> <span style="color: #000000;">items</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">xml_get_nodes</span><span style="color: #0000FF;">(</span><span style="color: #000000;">sections</span><span style="color: #0000FF;">[</span><span style="color: #000000;">s</span><span style="color: #0000FF;">],</span><span style="color: #008000;">"item"</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">if</span> <span style="color: #000000;">item1</span><span style="color: #0000FF;">={}</span> <span style="color: #008080;">then</span> <span style="color: #000000;">item1</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">items</span><span style="color: #0000FF;">[</span><span style="color: #000000;">1</span><span style="color: #0000FF;">]</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #008080;">for</span> <span style="color: #000000;">i</span><span style="color: #0000FF;">=</span><span style="color: #000000;">1</span> <span style="color: #008080;">to</span> <span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">items</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">do</span>
<span style="color: #000000;">prices</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">append</span><span style="color: #0000FF;">(</span><span style="color: #000000;">prices</span><span style="color: #0000FF;">,</span><span style="color: #000000;">xml_get_nodes</span><span style="color: #0000FF;">(</span><span style="color: #000000;">items</span><span style="color: #0000FF;">[</span><span style="color: #000000;">i</span><span style="color: #0000FF;">],</span><span style="color: #008000;">"price"</span><span style="color: #0000FF;">)[</span><span style="color: #000000;">1</span><span style="color: #0000FF;">][</span><span style="color: #000000;">XML_CONTENTS</span><span style="color: #0000FF;">])</span>
<span style="color: #000000;">names</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">append</span><span style="color: #0000FF;">(</span><span style="color: #000000;">names</span><span style="color: #0000FF;">,</span><span style="color: #000000;">xml_get_nodes</span><span style="color: #0000FF;">(</span><span style="color: #000000;">items</span><span style="color: #0000FF;">[</span><span style="color: #000000;">i</span><span style="color: #0000FF;">],</span><span style="color: #008000;">"name"</span><span style="color: #0000FF;">)[</span><span style="color: #000000;">1</span><span style="color: #0000FF;">][</span><span style="color: #000000;">XML_CONTENTS</span><span style="color: #0000FF;">])</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">for</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">for</span>
<span style="color: #7060A8;">puts</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"===item[1]===\n"</span><span style="color: #0000FF;">)</span>
<span style="color: #004080;">sequence</span> <span style="color: #000000;">tmp</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">xml_new_doc</span><span style="color: #0000FF;">(</span><span style="color: #000000;">item1</span><span style="color: #0000FF;">)</span>
<span style="color: #7060A8;">puts</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #7060A8;">xml_sprint</span><span style="color: #0000FF;">(</span><span style="color: #000000;">tmp</span><span style="color: #0000FF;">))</span>
<span style="color: #7060A8;">puts</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"===prices===\n"</span><span style="color: #0000FF;">)</span>
<span style="color: #7060A8;">pp</span><span style="color: #0000FF;">(</span><span style="color: #000000;">prices</span><span style="color: #0000FF;">)</span>
<span style="color: #7060A8;">puts</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"===names===\n"</span><span style="color: #0000FF;">)</span>
<span style="color: #7060A8;">pp</span><span style="color: #0000FF;">(</span><span style="color: #000000;">names</span><span style="color: #0000FF;">,{</span><span style="color: #004600;">pp_Maxlen</span><span style="color: #0000FF;">,</span><span style="color: #000000;">90</span><span style="color: #0000FF;">})</span>
<!--</syntaxhighlight>-->
{{out}}
<pre>
===item[1]===
<?xml version="1.0" encoding="utf-8" ?>
<item upc="123456789" stock="12">
<name>Invisibility Cream</name>
<price>14.50</price>
<description>Makes you invisible</description>
</item>
===prices===
{`14.50`, `23.99`, `4.95`, `3.56`}
===names===
{`Invisibility Cream`, `Levitation Salve`, `Blork and Freen Instameal`, `Grob winglets`}
</pre>


=={{header|PHP}}==
=={{header|PHP}}==
<lang php><?php
<syntaxhighlight lang="php"><?php
//PHP5 only example due to changes in XML extensions between version 4 and 5 (Tested on PHP5.2.0)
//PHP5 only example due to changes in XML extensions between version 4 and 5 (Tested on PHP5.2.0)
$doc = DOMDocument::loadXML('<inventory title="OmniCorp Store #45x10^3">...</inventory>');
$doc = DOMDocument::loadXML('<inventory title="OmniCorp Store #45x10^3">...</inventory>');
Line 1,626: Line 3,100:
{
{
$result[] = $node;
$result[] = $node;
}</lang>
}</syntaxhighlight>


=={{header|PicoLisp}}==
=={{header|PicoLisp}}==
<lang PicoLisp>(load "@lib/xm.l")
<syntaxhighlight lang="picolisp">(load "@lib/xm.l")


(let Sections (body (in "file.xml" (xml)))
(let Sections (body (in "file.xml" (xml)))
Line 1,640: Line 3,114:
(for S Sections
(for S Sections
(for L (body S)
(for L (body S)
(link (car (body L 'name))) ) ) ) )</lang>
(link (car (body L 'name))) ) ) ) )</syntaxhighlight>
Output:
Output:
<pre>(item
<pre>(item
Line 1,652: Line 3,126:
3.56
3.56
-> ("Invisibility Cream" "Levitation Salve" "Blork and Freen Instameal" "Grob winglets")</pre>
-> ("Invisibility Cream" "Levitation Salve" "Blork and Freen Instameal" "Grob winglets")</pre>

=={{header|PowerShell}}==
Cast the <code>$document</code> string as <code>[xml]</code> and you have access to .NET methods affecting XML.
<syntaxhighlight lang="powershell">
$document = [xml]@'
<inventory title="OmniCorp Store #45x10^3">
<section name="health">
<item upc="123456789" stock="12">
<name>Invisibility Cream</name>
<price>14.50</price>
<description>Makes you invisible</description>
</item>
<item upc="445322344" stock="18">
<name>Levitation Salve</name>
<price>23.99</price>
<description>Levitate yourself for up to 3 hours per application</description>
</item>
</section>
<section name="food">
<item upc="485672034" stock="653">
<name>Blork and Freen Instameal</name>
<price>4.95</price>
<description>A tasty meal in a tablet; just add water</description>
</item>
<item upc="132957764" stock="44">
<name>Grob winglets</name>
<price>3.56</price>
<description>Tender winglets of Grob. Just add water</description>
</item>
</section>
</inventory>
'@

$query = "/inventory/section/item"
$items = $document.SelectNodes($query)
</syntaxhighlight>
The first item:
<syntaxhighlight lang="powershell">
$items[0]
</syntaxhighlight>
{{Out}}
<pre>
upc : 123456789
stock : 12
name : Invisibility Cream
price : 14.50
description : Makes you invisible
</pre>
Get some useful information:
<syntaxhighlight lang="powershell">
$namesAndPrices = $items | Select-Object -Property name, price
$namesAndPrices
</syntaxhighlight>
{{Out}}
<pre>
name price
---- -----
Invisibility Cream 14.50
Levitation Salve 23.99
Blork and Freen Instameal 4.95
Grob winglets 3.56
</pre>
Here are the prices:
<syntaxhighlight lang="powershell">
$items.price
</syntaxhighlight>
{{Out}}
<pre>
14.50
23.99
4.95
3.56
</pre>
Here are the names:
<syntaxhighlight lang="powershell">
$items.name
</syntaxhighlight>
{{Out}}
<pre>
Invisibility Cream
Levitation Salve
Blork and Freen Instameal
Grob winglets
</pre>


=={{header|Python}}==
=={{header|Python}}==
<lang python># Python has basic xml parsing built in
<syntaxhighlight lang="python"># Python has basic xml parsing built in


from xml.dom import minidom
from xml.dom import minidom
Line 1,671: Line 3,229:


# 3rd Task: Get an array of all the "name" elements
# 3rd Task: Get an array of all the "name" elements
namesArray = xmldoc.getElementsByTagName("name")</lang>
namesArray = xmldoc.getElementsByTagName("name")</syntaxhighlight>
In Python 2.5+ you can use ElementTree's limited XPath support
In Python 2.5+ you can use ElementTree's limited XPath support
<lang python>
<syntaxhighlight lang="python">
import xml.etree.ElementTree as ET
import xml.etree.ElementTree as ET


Line 1,691: Line 3,249:


# list of names
# list of names
names = doc.findall("section/item/name") # or ".//name"</lang>
names = doc.findall("section/item/name") # or ".//name"</syntaxhighlight>
Or, you can install the <tt>lxml</tt> package and get full XPath support
Or, you can install the <tt>lxml</tt> package and get full XPath support
<lang python>
<syntaxhighlight lang="python">
from lxml import etree
from lxml import etree


Line 1,708: Line 3,266:
print "{0:0.2f}".format(float(p.text)) # could raise exception on missing text or invalid float() conversion
print "{0:0.2f}".format(float(p.text)) # could raise exception on missing text or invalid float() conversion


names = doc.xpath("//name") # list of names</lang>
names = doc.xpath("//name") # list of names</syntaxhighlight>


=={{header|R}}==
=={{header|R}}==
{{libheader|XML (R)}}
{{libheader|XML (R)}}
<syntaxhighlight lang="r">
<lang R>## Require the XML package you can download from http://www.omegahat.org/RSXML/
library("XML")
library("XML")
doc <- xmlInternalTreeParse("test3.xml")
doc <- xmlInternalTreeParse("test3.xml")

# 1st Task: Retrieve the first "item" element
# Retrieve the first "item" element
(firstItemElement <- getNodeSet(doc, "//item")[[1]])
getNodeSet(doc, "//item")[[1]]
# 2nd task: Perform an action on each "price" element (print it out)

prices <- sapply(getNodeSet(doc, "//price"), xmlValue)
# Perform an action on each "price" element
for(i in 1:length(prices)) print(prices[i])
sapply(getNodeSet(doc, "//price"), xmlValue)
# 3rd Task: Get an array of all the "name" elements

(namesArray <- sapply(getNodeSet(doc, "//name"), xmlValue))</lang>
# Get an array of all the "name" elements
sapply(getNodeSet(doc, "//name"), xmlValue)

</syntaxhighlight>


=={{header|Racket}}==
=={{header|Racket}}==
<lang racket>
<syntaxhighlight lang="racket">
#lang at-exp racket
#lang at-exp racket


Line 1,772: Line 3,334:
(se-path*/list '(item name) data)
(se-path*/list '(item name) data)
;; => '("Invisibility Cream" "Levitation Salve" "Blork and Freen Instameal" "Grob winglets")
;; => '("Invisibility Cream" "Levitation Salve" "Blork and Freen Instameal" "Grob winglets")
</syntaxhighlight>
</lang>

=={{header|Raku}}==
(formerly Perl 6)

<syntaxhighlight lang="raku" line>use XML::XPath;

my $XML = XML::XPath.new(xml => q:to/END/);
<inventory title="OmniCorp Store #45x10^3">
<section name="health">
<item upc="123456789" stock="12">
<name>Invisibility Cream</name>
<price>14.50</price>
<description>Makes you invisible</description>
</item>
<item upc="445322344" stock="18">
<name>Levitation Salve</name>
<price>23.99</price>
<description>Levitate yourself for up to 3 hours per application</description>
</item>
</section>
<section name="food">
<item upc="485672034" stock="653">
<name>Blork and Freen Instameal</name>
<price>4.95</price>
<description>A tasty meal in a tablet; just add water</description>
</item>
<item upc="132957764" stock="44">
<name>Grob winglets</name>
<price>3.56</price>
<description>Tender winglets of Grob. Just add water</description>
</item>
</section>
</inventory>
END

put "First item:\n", $XML.find('//item[1]')[0];

put "\nPrice elements:";
.contents.put for $XML.find('//price').List;

put "\nName elements:\n", $XML.find('//name')».contents.join: ', ';</syntaxhighlight>
{{out}}
<pre>First item:
<item upc="123456789" stock="12"> <name>Invisibility Cream</name> <price>14.50</price> <description>Makes you invisible</description> </item>

Price elements:
14.50
23.99
4.95
3.56

Name elements:
Invisibility Cream, Levitation Salve, Blork and Freen Instameal, Grob winglets</pre>


=={{header|Rascal}}==
=={{header|Rascal}}==
<lang rascal>import lang::xml::DOM;
<syntaxhighlight lang="rascal">import lang::xml::DOM;
import Prelude;
import Prelude;


Line 1,797: Line 3,412:
L += n;
L += n;
return L;
return L;
}</lang>
}</syntaxhighlight>
Example output:
Example output:
<lang rascal>rascal>get_first_item(|file:///Users/.../Desktop/xmlpath.xml|)
<syntaxhighlight lang="rascal">rascal>get_first_item(|file:///Users/.../Desktop/xmlpath.xml|)
<?xml version="1.0" encoding="UTF-8"?>
<?xml version="1.0" encoding="UTF-8"?>
<item stock="12" upc="123456789">
<item stock="12" upc="123456789">
Line 1,818: Line 3,433:


rascal>get_names(|file:///Users/.../Desktop/xmlpath.xml|)
rascal>get_names(|file:///Users/.../Desktop/xmlpath.xml|)
list[str]: ["Invisibility Cream","Levitation Salve","Blork and Freen Instameal","Grob winglets"]</lang>
list[str]: ["Invisibility Cream","Levitation Salve","Blork and Freen Instameal","Grob winglets"]</syntaxhighlight>


=={{header|REXX}}==
=={{header|REXX}}==
===hard coded parsing===
===hard coded parsing===
<lang rexx>/*REXX program to parse various queries on an XML document (from a file)*/
<syntaxhighlight lang="rexx">/*REXX program to parse various queries on an XML document (from a file). */
iFID='XPATH.XML' /*name of the input XML file(doc)*/
iFID='XPATH.XML' /*name of the input XML file (doc). */
$= /*string will contain file's text*/
$= /*string will contain the file's text. */
do j=1 while lines(iFID)\==0 /*read the entire file into a str*/
do j=1 while lines(iFID)\==0 /*read the entire file into a string. */
$=$ linein(iFID) /*append the line to the $ string*/
$=$ linein(iFID) /*append the line to the $ string. */
end /*j*/
end /*j*/
/* [↓] show 1st ITEM in the doc*/
/* [↓] show 1st ITEM in the document*/
parse var $ '<item ' item "</item>"
parse var $ '<item ' item "</item>"
say center('first item:',length(space(item)),'─') /*show a nice header*/
say center('first item:',length(space(item)),'─') /*display a nice header.*/
say space(item)
say space(item)
/* [↓] show all PRICES in the doc*/
/* [↓] show all PRICES in the document*/
prices= /*nullify the list and add to it.*/
prices= /*nullify the list and add/append to it*/
$$=$ /*start with a fresh copy of doc.*/
$$=$ /*start with a fresh copy of document. */
do until $$='' /* [↓] keep parsing until done. */
do until $$='' /* [↓] keep parsing string until done.*/
parse var $$ '<price>' price '</price>' $$
parse var $$ '<price>' price '</price>' $$
prices=prices price /*added the price to the list. */
prices=prices price /*add/append the price to the list. */
end /*until*/
end /*until*/
say
say
say center('prices:',length(space(prices)),'─') /*show a nice header*/
say center('prices:',length(space(prices)),'─') /*display a nice header.*/
say space(prices)
say space(prices)
/* [↓] show all NAMES in the doc*/
/* [↓] show all NAMES in the document*/
names.= /*nullify the list and add to it.*/
names.= /*nullify the list and add/append to it*/
L=length(' names: ') /*maximum length of any one name.*/
L=length(' names: ') /*maximum length of any one list name. */
$$=$ /*start with a fresh copy of doc.*/
$$=$ /*start with a fresh copy of document. */
do #=1 until $$='' /* [↓] keep parsing until done. */
do #=1 until $$='' /* [↓] keep parsing string until done.*/
parse var $$ '<name>' names.# '</name>' $$
parse var $$ '<name>' names.# '</name>' $$
L=max(L,length(names.#)) /*used to find the widest name. */
L=max(L,length(names.#)) /*L: is used to find the widest name. */
end /*#*/
end /*#*/


names.0=#-1 /*adjust the # of names (DO loop)*/
names.0=#-1; say /*adjust the number of names (DO loop).*/
say center('names:',L,'─') /*display a nicely formatted header. */
say
say center('names:',L,'─') /*show a nicely formatted header.*/
do k=1 for names.0 /*display all the names in the list. */
do k=1 for names.0 /*show all the names in the list.*/
say names.k /*display a name from the NAMES list.*/
say names.k /*show a name from the NAMES list*/
end /*k*/
end /*k*/
exit /*stick a fork in it, we're done.*/</lang>
/*stick a fork in it, we're all done. */</syntaxhighlight>
'''output'''
'''output'''
<pre>
<pre>
Line 1,874: Line 3,488:


===generic parsing===
===generic parsing===
<lang rexx>/*REXX program to parse various queries on an XML document (from a file)*/
<syntaxhighlight lang="rexx">/*REXX program to parse various queries on an XML document (from a file). */
iFID='XPATH.XML' /*name of the input XML file(doc)*/
iFID='XPATH.XML' /*name of the input XML file (doc). */
$= /*string will contain file's text*/
$= /*string will contain the file's text. */
do j=1 while lines(iFID)\==0 /*read the entire file into a str*/
do j=1 while lines(iFID)\==0 /*read the entire file into a string. */
$=$ linein(iFID) /*append the line to the $ string*/
$=$ linein(iFID) /*append the line to the $ string. */
end /*j*/
end /*j*/
/* [↓] display 1st ITEM in document. */
call parser 'item', 0 /*go and parse the all the ITEMs. */
say center('first item:',@L.1,'─') /*display a nicely formatted header. */
say @.1; say /*display the first ITEM found. */


call parser 'item', 0 /*go and parse the all ITEMs. */
call parser 'price' /*go and parse all the PRICEs. */
say center('first item:',@L.1,'─') /*show a nicely formatted header.*/
say center('prices:',length(@@@),'─') /*display a nicely formatted header. */
say @.1 /*show the first ITEM found. */
say @@@; say /*display a list of all the prices. */
say

call parser 'price' /*go and parse all the PRICEs. */
say center('prices:',length(@@@),'─') /*show a nicely formatted header.*/
say @@@ /*show a list of all the prices. */
say


call parser 'name'
call parser 'name'
say center('names:',@L,'─') /*show a nicely formatted header.*/
say center('names:',@L,'─') /*display a nicely formatted header. */
do k=1 for # /*show all the names in the list.*/
do k=1 for # /*display all the names in the list. */
say @.k /*show a name from the NAMES list*/
say @.k /*display a name from the NAMES list.*/
end /*k*/
end /*k*/
exit /*stick a fork in it, we're done.*/
exit /*stick a fork in it, we're all done. */
/*────────────────────────────────────────────────────────────────────────────*/
/*──────────────────────────────────PARSER subroutine───────────────────*/
parser: parse arg yy,tail,,@. @@. @@@; $$=$; @L=9; yb='<'yy; ye='</'yy">"
parser: parse arg yy,tail,,@. @@. @@@; $$=$; @L=9; yb='<'yy; ye='</'yy">"
tail=word(tail 1, 1) /*use a tail ">" or not?*/
tail=word(tail 1, 1) /*use a tail ">" or not?*/
do #=1 until $$='' /*parse complete XML doc*/
do #=1 until $$='' /*parse complete XML doc. */
if tail then parse var $$ (yb) '>' @@.# (ye) $$ /*find meat*/
if tail then parse var $$ (yb) '>' @@.# (ye) $$ /*find meat.*/
else parse var $$ (yb) @@.# (ye) $$ /* " " */
else parse var $$ (yb) @@.# (ye) $$ /* " " */
@.#=space(@@.#); @@@=space(@@@ @.#) /*shrink; @@@=list of YY*/
@.#=space(@@.#); @@@=space(@@@ @.#) /*shrink; @@@=list of YY.*/
@L.#=length(@.#); @L=max(@L,@L.#) /*YY length, max length.*/
@L.#=length(@.#); @L=max(@L,@L.#) /*length; maximum length. */
end /*#*/
end /*#*/
#=#-1 /*adjust # things found.*/
#=#-1 /*adjust # of thing found.*/
return</lang>
return</syntaxhighlight>
'''output''' is the same as the 1<sup>st</sup> version.
'''output''' &nbsp; is the same as the 1<sup>st</sup> version.


=={{header|Ruby}}==
=={{header|Ruby}}==
{{libheader|REXML}}
{{libheader|REXML}}
<lang ruby>#Example taken from the REXML tutorial (http://www.germane-software.com/software/rexml/docs/tutorial.html)
<syntaxhighlight lang="ruby">#Example taken from the REXML tutorial (http://www.germane-software.com/software/rexml/docs/tutorial.html)
require "rexml/document"
require "rexml/document"
include REXML
include REXML
Line 1,927: Line 3,539:
XPath.each( doc, "//price") { |element| puts element.text }
XPath.each( doc, "//price") { |element| puts element.text }
# Gets an array of all of the "name" elements in the document.
# Gets an array of all of the "name" elements in the document.
names = XPath.match( doc, "//name" )</lang>
names = XPath.match( doc, "//name" )</syntaxhighlight>


=={{header|Scala}}==
=={{header|Scala}}==
The problem description isn't clear on whether what
is wanted is the element or the text. Because of that,
I'm doing both except for the first problem.


The commands are being inputted into Scala's REPL, to
The code is entered in to Scala's REPL, to
better show the results.
better show the results.


<syntaxhighlight lang="scala">
<lang scala>scala> val xml = <inventory title="OmniCorp Store #45x10^3">
scala> val xml: scala.xml.Elem =
| <inventory title="OmniCorp Store #45x10^3">
| <section name="health">
| <section name="health">
| <item upc="123456789" stock="12">
| <item upc="123456789" stock="12">
Line 1,963: Line 3,574:
| </section>
| </section>
| </inventory>
| </inventory>
xml: scala.xml.Elem =
<inventory title="OmniCorp Store #45x10^3">
<section name="health">
<item upc="123456789" stock="12">
<name>Invisibility Cream</name>
<price>14.50</price>
<description>Makes you invisible</description>
</item>
<item upc="445322344" stock="18">
<name>Levitation Salve</name>
<price>23.99</price>
<description>Levitate yourself for up to 3 hours per application</description>
</item>
</section>
<section name="food">
<item upc="485672034" stock="653">
<name>Blork and Freen Instameal</name>
<price>4.95</price>
<description>A tasty meal in a tablet; just add water</description>
</item>
<item upc="132957764" stock="44">
<name>Grob winglets</name>
<price>3.56</price>
<description>Tender winglets of Grob. Just add water</description>
</item>
</section>
</inventory>


scala> val firstItem = xml \\ "item" head
scala> val firstItem = xml \\ "item" take 1
firstItem: scala.xml.Node =
firstItem: scala.xml.NodeSeq =
<item upc="123456789" stock="12">
NodeSeq(<item upc="123456789" stock="12">
<name>Invisibility Cream</name>
<name>Invisibility Cream</name>
<price>14.50</price>
<price>14.50</price>
<description>Makes you invisible</description>
<description>Makes you invisible</description>
</item>
</item>)

scala> xml \\ "price" foreach println
<price>14.50</price>
<price>23.99</price>
<price>4.95</price>
<price>3.56</price>


scala> xml \\ "price" map (_ text) foreach println
scala> xml \\ "price" map (_.text) foreach println
14.50
14.50
23.99
23.99
Line 2,011: Line 3,589:
3.56
3.56


scala> val elements = xml \\ "name" toArray
scala> val names = (xml \\ "name").toArray
elements: Array[scala.xml.Node] = Array(<name>Invisibility Cream</name>, <name>Levitation Salve</name>, <name>Blork and
names: Array[scala.xml.Node] = Array(<name>Invisibility Cream</name>, <name>Levitation Salve</name>, <name>Blork and Freen Instameal</name>, <name>Grob winglets</name>)</syntaxhighlight>
Freen Instameal</name>, <name>Grob winglets</name>)


=={{header|SenseTalk}}==
scala> val values = xml \\ "name" map (_ text) toArray
<syntaxhighlight lang="sensetalk">Set XMLSource to {{
values: Array[String] = Array(Invisibility Cream, Levitation Salve, Blork and Freen Instameal, Grob winglets)</lang>
<inventory title="OmniCorp Store #45x10^3">
<section name="health">
<item upc="123456789" stock="12">
<name>Invisibility Cream</name>
<price>14.50</price>
<description>Makes you invisible</description>
</item>
<item upc="445322344" stock="18">
<name>Levitation Salve</name>
<price>23.99</price>
<description>Levitate yourself for up to 3 hours per application</description>
</item>
</section>
<section name="food">
<item upc="485672034" stock="653">
<name>Blork and Freen Instameal</name>
<price>4.95</price>
<description>A tasty meal in a tablet; just add water</description>
</item>
<item upc="132957764" stock="44">
<name>Grob winglets</name>
<price>3.56</price>
<description>Tender winglets of Grob. Just add water</description>
</item>
</section>
</inventory>
}}

put node "//item[1]" of XMLSource
put node "//price/text()" of XMLSource
put all nodes "//name" of XMLSource</syntaxhighlight>

{{out}}
<pre>
<item upc="123456789" stock="12">
<name>Invisibility Cream</name>
<price>14.50</price>
<description>Makes you invisible</description>
</item>
14.50
(<name>Invisibility Cream</name>,<name>Levitation Salve</name>,<name>Blork and Freen Instameal</name>,<name>Grob winglets</name>)
</pre>

=={{header|Sidef}}==
{{trans|Perl}}
<syntaxhighlight lang="ruby">require('XML::XPath');

var x = %s'XML::XPath'.new(ARGF.slurp);

[x.findnodes('//item[1]')][0];
say [x.findnodes('//price')].map{x.getNodeText(_)};
[x.findnodes('//name')];</syntaxhighlight>

{{out}}
<pre>
[14.5, 23.99, 4.95, 3.56]
</pre>


=={{header|Tcl}}==
=={{header|Tcl}}==
{{libheader|tDOM}}
{{libheader|tDOM}}
<lang tcl># assume $xml holds the XML data
<syntaxhighlight lang="tcl"># assume $xml holds the XML data
package require tdom
package require tdom
set doc [dom parse $xml]
set doc [dom parse $xml]
Line 2,033: Line 3,667:
foreach node [$root selectNodes //price] {
foreach node [$root selectNodes //price] {
puts [$node text]
puts [$node text]
}</lang>
}</syntaxhighlight>

=={{header|TUSCRIPT}}==
=={{header|TUSCRIPT}}==
<lang tuscript>
<syntaxhighlight lang="tuscript">
$$ MODE TUSCRIPT,{}
$$ MODE TUSCRIPT,{}
MODE DATA
MODE DATA
Line 2,098: Line 3,733:
names=SPLIT(names)
names=SPLIT(names)
TRACE *firstitem,names
TRACE *firstitem,names
</syntaxhighlight>
</lang>
Output:
Output:
<pre style='height:30ex;overflow:scroll'>
<pre style='height:30ex;overflow:scroll'>
Line 2,117: Line 3,752:
3 = Blork and Freen Instameal
3 = Blork and Freen Instameal
4 = Grob winglets
4 = Grob winglets
</pre>

=={{header|VBScript}}==
<syntaxhighlight lang="vb">
Set objXMLDoc = CreateObject("msxml2.domdocument")

objXMLDoc.load("In.xml")

Set item_nodes = objXMLDoc.selectNodes("//item")
i = 1
For Each item In item_nodes
If i = 1 Then
WScript.StdOut.Write item.xml
WScript.StdOut.WriteBlankLines(2)
Exit For
End If
Next

Set price_nodes = objXMLDoc.selectNodes("//price")
list_price = ""
For Each price In price_nodes
list_price = list_price & price.text & ", "
Next
WScript.StdOut.Write list_price
WScript.StdOut.WriteBlankLines(2)

Set name_nodes = objXMLDoc.selectNodes("//name")
list_name = ""
For Each name In name_nodes
list_name = list_name & name.text & ", "
Next
WScript.StdOut.Write list_name
WScript.StdOut.WriteBlankLines(2)
</syntaxhighlight>
{{out}}
<pre>
<item upc="123456789" stock="12">
<name>Invisibility Cream</name>
<price>14.50</price>
<description>Makes you invisible</description>
</item>

14.50, 23.99, 4.95, 3.56,

Invisibility Cream, Levitation Salve, Blork and Freen Instameal, Grob winglets,
</pre>
</pre>


=={{header|Visual Basic .NET}}==
=={{header|Visual Basic .NET}}==


<lang vbnet>Dim first_item = xml.XPathSelectElement("//item")
<syntaxhighlight lang="vbnet">Dim first_item = xml.XPathSelectElement("//item")
Console.WriteLine(first_item)
Console.WriteLine(first_item)
Line 2,128: Line 3,808:
Next
Next
Dim names = (From item In xml.XPathSelectElements("//name") Select item.Value).ToArray</lang>
Dim names = (From item In xml.XPathSelectElements("//name") Select item.Value).ToArray</syntaxhighlight>


=={{header|Wren}}==
{{libheader|Wren-pattern}}
Wren does not have built-in support for XML/XPath and, to my knowledge, there is no third party module which adds such support either. We therefore have to fall back on string pattern matching to perform the required queries.
<syntaxhighlight lang="wren">import "./pattern" for Pattern

var doc = """
<inventory title="OmniCorp Store #45x10^3">
<section name="health">
<item upc="123456789" stock="12">
<name>Invisibility Cream</name>
<price>14.50</price>
<description>Makes you invisible</description>
</item>
<item upc="445322344" stock="18">
<name>Levitation Salve</name>
<price>23.99</price>
<description>Levitate yourself for up to 3 hours per application</description>
</item>
</section>
<section name="food">
<item upc="485672034" stock="653">
<name>Blork and Freen Instameal</name>
<price>4.95</price>
<description>A tasty meal in a tablet; just add water</description>
</item>
<item upc="132957764" stock="44">
<name>Grob winglets</name>
<price>3.56</price>
<description>Tender winglets of Grob. Just add water</description>
</item>
</section>
</inventory>
"""

var p1 = Pattern.new("<item ")
var match1 = p1.find(doc)
var p2 = Pattern.new("<//item>")
var match2 = p2.find(doc)
System.print("The first 'item' element is:")
System.print(" " + doc[match1.index..match2.index + 6])

var p3 = Pattern.new("<price>[+1^<]<//price>")
var matches = p3.findAll(doc)
System.print("\nThe 'prices' are:")
for (m in matches) System.print(m.captures[0].text)

var p4 = Pattern.new("<name>[+1^<]<//name>")
var matches2 = p4.findAll(doc)
var names = matches2.map { |m| m.captures[0].text }.toList
System.print("\nThe 'names' are:")
System.print(names.join("\n"))</syntaxhighlight>

{{out}}
<pre>
The first 'item' element is:
<item upc="123456789" stock="12">
<name>Invisibility Cream</name>
<price>14.50</price>
<description>Makes you invisible</description>
</item>

The 'prices' are:
14.50
23.99
4.95
3.56

The 'names' are:
Invisibility Cream
Levitation Salve
Blork and Freen Instameal
Grob winglets
</pre>
<br>
{{libheader|Wren-xsequence}}
Since the first version was written, the above XML parser has appeared. Consequently, the solution can now be rewritten as follows, the output being the same as before.

Note that this library doesn't support XPath as such though for this particular task simple 'for' statements suffice.
<syntaxhighlight lang="wren">import "./xsequence" for XDocument

var xml = """
<inventory title="OmniCorp Store #45x10^3">
<section name="health">
<item upc="123456789" stock="12">
<name>Invisibility Cream</name>
<price>14.50</price>
<description>Makes you invisible</description>
</item>
<item upc="445322344" stock="18">
<name>Levitation Salve</name>
<price>23.99</price>
<description>Levitate yourself for up to 3 hours per application</description>
</item>
</section>
<section name="food">
<item upc="485672034" stock="653">
<name>Blork and Freen Instameal</name>
<price>4.95</price>
<description>A tasty meal in a tablet; just add water</description>
</item>
<item upc="132957764" stock="44">
<name>Grob winglets</name>
<price>3.56</price>
<description>Tender winglets of Grob. Just add water</description>
</item>
</section>
</inventory>
"""

var doc = XDocument.parse(xml)
System.print("The first 'item' element is:")
System.print(doc.root.element("section").element("item"))

var prices = []
var names = []
for (el in doc.root.elements) {
for (el2 in el.elements) {
prices.add(el2.element("price").value)
names.add(el2.element("name").value)
}
}
System.print("\nThe 'prices' are:\n%(prices.join("\n"))")
System.print("\nThe 'names' are:\n%(names.join("\n"))")</syntaxhighlight>

=={{header|XPL0}}==
To run: xml <xml.xml
<syntaxhighlight lang "XPL0">include xpllib; \for StrFind

char XML(1000000), P, P1, P2, Addr;
int I, Ch;
[I:= 0;
loop [Ch:= ChIn(1);
XML(I):= Ch;
if Ch = $1A \EOF\ then quit;
I:= I+1;
];
XML(I):= 0;

P1:= StrFind(XML, "<item ");
P2:= StrFind(XML, "</item>");
Text(0, "The first 'item' element is:^m^j");
for P:= P1 to P2+6 do ChOut(0, P(0));
CrLf(0);

Text(0, "^m^jThe 'prices' are:^m^j");
Addr:= XML;
loop [P1:= StrFind(Addr, "<price>");
if P1 = 0 then quit;
P2:= StrFind(Addr, "</price>");
if P2 = 0 then quit;
for P:= P1+7 to P2-1 do ChOut(0, P(0));
CrLf(0);
Addr:= P2+1;
];
Text(0, "^m^jThe 'names' are:^m^j");
Addr:= XML;
loop [P1:= StrFind(Addr, "<name>");
if P1 = 0 then quit;
P2:= StrFind(Addr, "</name>");
if P2 = 0 then quit;
for P:= P1+6 to P2-1 do ChOut(0, P(0));
CrLf(0);
Addr:= P2+1;
];
]</syntaxhighlight>
{{out}}
<pre>
The first 'item' element is:
<item upc="123456789" stock="12">
<name>Invisibility Cream</name>
<price>14.50</price>
<description>Makes you invisible</description>
</item>

The 'prices' are:
14.50
23.99
4.95
3.56

The 'names' are:
Invisibility Cream
Levitation Salve
Blork and Freen Instameal
Grob winglets
</pre>


=={{header|XProc}}==
=={{header|XProc}}==
<lang xml><p:pipeline xmlns:p="http://www.w3.org/ns/xproc"
<syntaxhighlight lang="xml"><p:pipeline xmlns:p="http://www.w3.org/ns/xproc"
name="one-two-three"
name="one-two-three"
version="1.0">
version="1.0">
Line 2,161: Line 4,027:
</p:input>
</p:input>
</p:insert>
</p:insert>
</p:pipeline></lang>
</p:pipeline></syntaxhighlight>

=={{header|XQuery}}==
=={{header|XQuery}}==
<lang xquery>(:
<syntaxhighlight lang="xquery">(:
1. Retrieve the first "item" element
1. Retrieve the first "item" element
Notice the braces around //item. This evaluates first all item elements and then retrieving the first one.
Notice the braces around //item. This evaluates first all item elements and then retrieving the first one.
Line 2,181: Line 4,048:
<prices>{$price}</prices>
<prices>{$price}</prices>
<names>{$names}</names>
<names>{$names}</names>
</result></lang>
</result></syntaxhighlight>


Performing this XQuery on the given input document results in
Performing this XQuery on the given input document results in
<lang xquery><?xml version="1.0" encoding="UTF-8"?>
<syntaxhighlight lang="xquery"><?xml version="1.0" encoding="UTF-8"?>
<result>
<result>
<firstItem>
<firstItem>
Line 2,200: Line 4,067:
<name>Grob winglets</name>
<name>Grob winglets</name>
</names>
</names>
</result></lang>
</result></syntaxhighlight>


=={{header|XSLT}}==
=={{header|XSLT}}==
<lang xml><xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<syntaxhighlight lang="xml"><xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="text" />
<xsl:output method="text" />
<xsl:template match="/">
<xsl:template match="/">
Line 2,226: Line 4,093:
<xsl:copy-of select="//name" />
<xsl:copy-of select="//name" />
</xsl:template>
</xsl:template>
</xsl:stylesheet></lang>
</xsl:stylesheet></syntaxhighlight>


{{omit from|Batch File|No way of XML parsing or processing.}}
{{omit from|Batch File|No way of XML parsing or processing.}}

Latest revision as of 20:44, 27 March 2024

Task
XML/XPath
You are encouraged to solve this task according to the task description, using any language you may know.

Perform the following three XPath queries on the XML Document below:

  • //item[1]: Retrieve the first "item" element
  • //price/text(): Perform an action on each "price" element (print it out)
  • //name: Get an array of all the "name" elements

XML Document: 

<inventory title="OmniCorp Store #45x10^3">
  

    <item upc="123456789" stock="12">
      <name>Invisibility Cream</name>
      <price>14.50</price>
      <description>Makes you invisible</description>
    </item>
    <item upc="445322344" stock="18">
      <name>Levitation Salve</name>
      <price>23.99</price>
      <description>Levitate yourself for up to 3 hours per application</description>
    </item>
  

  

    <item upc="485672034" stock="653">
      <name>Blork and Freen Instameal</name>
      <price>4.95</price>
      <description>A tasty meal in a tablet; just add water</description>
    </item>
    <item upc="132957764" stock="44">
      <name>Grob winglets</name>
      <price>3.56</price>
      <description>Tender winglets of Grob. Just add water</description>
    </item>
  

</inventory>

AArch64 Assembly

Works with: as version Raspberry Pi 3B version Buster 64 bits
/* ARM assembly AARCH64 Raspberry PI 3B */
/*  program xpathXml64.s   */
 
/*******************************************/
/* Constantes file                         */
/*******************************************/
/* for this file see task include a file in language AArch64 assembly*/
.include "../includeConstantesARM64.inc"
 
.equ NBMAXELEMENTS,    100
 
/*******************************************/
/* Structures                               */
/********************************************/
/* structure xmlNode*/
    .struct  0
xmlNode_private:                         // application data
    .struct  xmlNode_private + 8 
xmlNode_type:                            // type number, must be second !
    .struct  xmlNode_type + 8
xmlNode_name:                            // the name of the node, or the entity
    .struct  xmlNode_name + 8 
xmlNode_children:                        // parent->childs link
    .struct  xmlNode_children + 8
xmlNode_last:                            // last child link
    .struct  xmlNode_last + 8
xmlNode_parent:                          // child->parent link 
    .struct  xmlNode_parent + 8
xmlNode_next:                            // next sibling link
    .struct  xmlNode_next + 8
xmlNode_prev:                            // previous sibling link 
    .struct  xmlNode_prev + 8
xmlNode_doc:                             // the containing document
    .struct  xmlNode_doc + 8
xmlNode_ns:                              // pointer to the associated namespace
    .struct  xmlNode_ns + 8
xmlNode_content:                         // the content
    .struct  xmlNode_content + 8
xmlNode_properties:                      // properties list
    .struct  xmlNode_properties + 8
xmlNode_nsDef:                           // namespace definitions on this node 
    .struct  xmlNode_nsDef + 8
xmlNode_psvi:                            // for type/PSVI informations
    .struct  xmlNode_psvi + 8
xmlNode_line:                            // line number
    .struct  xmlNode_line + 4
xmlNode_extra:                           // extra data for XPath/XSLT
    .struct  xmlNode_extra + 4
xmlNode_fin:
/********************************************/
/* structure xmlNodeSet*/
    .struct  0
xmlNodeSet_nodeNr:                       // number of nodes in the set
    .struct  xmlNodeSet_nodeNr + 4
xmlNodeSet_nodeMax:                      // size of the array as allocated 
    .struct  xmlNodeSet_nodeMax + 4
xmlNodeSet_nodeTab:                      // array of nodes in no particular order
    .struct  xmlNodeSet_nodeTab + 8
xmlNodeSet_fin:
/********************************************/
/* structure xmlXPathObject*/
    .struct  0
xmlPathObj_type:                         //
    .struct  xmlPathObj_type + 8
xmlPathObj_nodesetval:                   //
    .struct  xmlPathObj_nodesetval + 8
xmlPathObj_boolval:                      //
    .struct  xmlPathObj_boolval + 8
xmlPathObj_floatval:                     //
    .struct  xmlPathObj_floatval + 8
xmlPathObj_stringval:                    //
    .struct  xmlPathObj_stringval + 8
xmlPathObj_user:                         //
    .struct  xmlPathObj_user + 8
xmlPathObj_index:                        //
    .struct  xmlPathObj_index + 8
xmlPathObj_usex2:                        //
    .struct  xmlPathObj_usex2 + 8
xmlPathObj_index2:                       //
    .struct  xmlPathObj_index2 + 8
/*********************************/
/* Initialized data              */
/*********************************/
.data
szMessEndpgm:      .asciz "\nNormal end of program.\n" 
szMessDisVal:      .asciz "\nDisplay set values.\n" 
szMessDisArea:     .asciz "\nDisplay area values.\n" 
szFileName:        .asciz "testXml.xml" 
szMessError:       .asciz "Error detected !!!!. \n"
 
 
szLibName:         .asciz "name"
szLibPrice:        .asciz "//price"
szLibExtName:      .asciz "//name"
szCarriageReturn:  .asciz "\n"
 
 
/*********************************/
/* UnInitialized data            */
/*********************************/
.bss 
.align 4
tbExtract:          .skip 8 * NBMAXELEMENTS      // result extract area
/*********************************/
/*  code section                 */
/*********************************/
.text
.global main 
main:                                     // entry of program 
    ldr x0,qAdrszFileName 
    bl xmlParseFile                       // create doc
    cbz x0,99f                            // error ?
    mov x19,x0                            // doc address
    mov x0,x19                            // doc
    bl xmlDocGetRootElement               // get root
    bl xmlFirstElementChild               // get first section
    bl xmlFirstElementChild               // get first item
    bl xmlFirstElementChild               // get first name
    bl xmlNodeGetContent                  // extract content
    bl affichageMess                      // for display
    ldr x0,qAdrszCarriageReturn
    bl affichageMess
 
    ldr x0,qAdrszMessDisVal
    bl affichageMess
    mov x0,x19
    ldr x1,qAdrszLibPrice                 // extract prices
    bl extractValue
    mov x0,x19
    ldr x1,qAdrszLibExtName               // extract names
    bl extractValue
    ldr x0,qAdrszMessDisArea
    bl affichageMess
    mov x4,#0                             // display string result area
    ldr x5,qAdrtbExtract
1:
    ldr x0,[x5,x4,lsl #3]
    cbz x0,2f
    bl affichageMess
    ldr x0,qAdrszCarriageReturn
    bl affichageMess
    add x4,x4,1
    b 1b
2:
    mov x0,x19
    bl xmlFreeDoc
    bl xmlCleanupParser
    ldr x0,qAdrszMessEndpgm
    bl affichageMess
    b 100f
99:                                       // error
    ldr x0,qAdrszMessError
    bl affichageMess       
100:                                      // standard end of the program 
    mov x0,0                              // return code
    mov x8,EXIT                           // request to exit program
    svc 0                                 // perform the system call
 
qAdrszMessError:          .quad szMessError
qAdrszMessEndpgm:         .quad szMessEndpgm
qAdrszLibName:            .quad szLibName
qAdrszLibPrice:           .quad szLibPrice
qAdrszCarriageReturn:     .quad szCarriageReturn
qAdrszFileName:           .quad szFileName
qAdrszLibExtName:         .quad szLibExtName
qAdrtbExtract:            .quad tbExtract
qAdrszMessDisVal:          .quad szMessDisVal
qAdrszMessDisArea:         .quad szMessDisArea
/******************************************************************/
/*     extract value of set                                       */ 
/******************************************************************/
/* x0 contains the doc address
/* x1 contains the address of the libel to extract */
extractValue:
    stp x19,lr,[sp,-16]!                 // save  registers
    stp x20,x21,[sp,-16]!                // save  registers
    stp x22,x23,[sp,-16]!                // save  registers
    mov x20,x1                           // save address libel
    mov x19,x0                           // save doc
    bl xmlXPathNewContext                // create context
    mov x23,x0                           // save context
    mov x1,x0
    mov x0,x20
    bl xmlXPathEvalExpression
    mov x21,x0
    mov x0,x23
    bl xmlXPathFreeContext               // free context
    cmp x21,#0
    beq 100f
    ldr x14,[x21,#xmlPathObj_nodesetval] // values set
    ldr w23,[x14,#xmlNodeSet_nodeNr]     // set size
    mov x22,#0                           // index
    ldr x20,[x14,#xmlNodeSet_nodeTab]    // area of nodes
    ldr x21,qAdrtbExtract
1:                                       // start loop 
    ldr x3,[x20,x22,lsl #3]              // load node
    mov x0,x19
    ldr x1,[x3,#xmlNode_children]        // load string value
    mov x2,#1
    bl xmlNodeListGetString
    str x0,[x21,x22,lsl #3]              // store string pointer in area
    bl affichageMess                     // and display string result
    ldr x0,qAdrszCarriageReturn
    bl affichageMess
    add x22,x22,1
    cmp x22,x23
    blt 1b
100:
    ldp x22,x23,[sp],16                  // restaur  2 registers
    ldp x20,x21,[sp],16                  // restaur  2 registers
    ldp x19,lr,[sp],16                   // restaur  2 registers
    ret                                  // return to address lr x30
/********************************************************/
/*        File Include fonctions                        */
/********************************************************/
/* for this file see task include a file in language AArch64 assembly */
.include "../includeARM64.inc"
Output:
Invisibility Cream

Display set values.
14.50
23.99
4.95
3.56
Invisibility Cream
Levitation Salve
Blork and Freen Instameal
Grob winglets

Display area values.
Invisibility Cream
Levitation Salve
Blork and Freen Instameal
Grob winglets

Normal end of program.

AppleScript

Using System Events

AppleScript has no-built in support for XPath, but it could be used via a 'do shell script' command. Here's a solution using Apple System Events. 

set theXMLdata to "<inventory title=\"OmniCorp Store #45x10^3\">
  <section name=\"health\">
    <item upc=\"123456789\" stock=\"12\">
      <name>Invisibility Cream</name>
      <price>14.50</price>
      <description>Makes you invisible</description>
    </item>
    <item upc=\"445322344\" stock=\"18\">
      <name>Levitation Salve</name>
      <price>23.99</price>
      <description>Levitate yourself for up to 3 hours per application</description>
    </item>
  </section>
  <section name=\"food\">
    <item upc=\"485672034\" stock=\"653\">
      <name>Blork and Freen Instameal</name>
      <price>4.95</price>
      <description>A tasty meal in a tablet; just add water</description>
    </item>
    <item upc=\"132957764\" stock=\"44\">
      <name>Grob winglets</name>
      <price>3.56</price>
      <description>Tender winglets of Grob. Just add water</description>
    </item>
  </section>
</inventory>"

on getElementValuesByName(theXML, theNameToFind)
	set R to {}
	tell application "System Events"
		repeat with i in theXML
			set {theName, theElements} to {i's name, i's XML elements}
			if (count of theElements) > 0 then set R to R & my getElementValuesByName(theElements, theNameToFind)
			if theName = theNameToFind then set R to R & i's value
		end repeat
	end tell
	return R
end getElementValuesByName

on getBlock(theXML, theItem, theInstance)
	set text item delimiters to ""
	repeat with i from 1 to theInstance
		set {R, blockStart, blockEnd} to {{}, "<" & theItem & space, "</" & theItem & ">"}
		set x to offset of blockStart in theXML
		if x = 0 then exit repeat
		set y to offset of blockEnd in (characters x thru -1 of theXML as string)
		if y = 0 then exit repeat
		set R to characters x thru (x + y + (length of blockEnd) - 2) of theXML as string
		set theXML to characters (y + (length of blockEnd)) thru -1 of theXML as string
	end repeat
	return R
end getBlock

tell application "System Events"
	set xmlData to make new XML data with properties {name:"xmldata", text:theXMLdata}
	
	return my getBlock(xmlData's text, "item", 1) -- Solution to part 1 of problem. 
	return my getElementValuesByName(xmlData's contents, "name") -- Solution to part 2 of problem.
	return my getElementValuesByName(xmlData's contents, "price") -- Solution to part 3 of problem.
	
end tell

Output for the three results (respectively):

"<item upc=\"123456789\" stock=\"12\">
      <name>Invisibility Cream</name>
      <price>14.50</price>
      <description>Makes you invisible</description>
    </item>"

{"Invisibility Cream", "Levitation Salve", "Blork and Freen Instameal", "Grob winglets"}

{"14.50", "23.99", "4.95", "3.56"}

ARM Assembly

Works with: as version Raspberry Pi
/* ARM assembly Raspberry PI  */
/*  program xpathXml.s   */

/* Constantes    */
.equ STDOUT, 1     @ Linux output console
.equ EXIT,   1     @ Linux syscall
.equ WRITE,  4     @ Linux syscall

.equ NBMAXELEMENTS,    100

/*******************************************/
/* Structures                               */
/********************************************/
/* structure xmlNode*/
    .struct  0
xmlNode_private:                         @ application data
    .struct  xmlNode_private + 4 
xmlNode_type:                            @ type number, must be second !
    .struct  xmlNode_type + 4 
xmlNode_name:                            @ the name of the node, or the entity
    .struct  xmlNode_name + 4 
xmlNode_children:                        @ parent->childs link
    .struct  xmlNode_children + 4 
xmlNode_last:                            @ last child link
    .struct  xmlNode_last + 4 
xmlNode_parent:                          @ child->parent link 
    .struct  xmlNode_parent + 4 
xmlNode_next:                            @ next sibling link
    .struct  xmlNode_next + 4 
xmlNode_prev:                            @ previous sibling link 
    .struct  xmlNode_prev + 4 
xmlNode_doc:                             @ the containing document
    .struct  xmlNode_doc + 4 
xmlNode_ns:                              @ pointer to the associated namespace
    .struct  xmlNode_ns + 4 
xmlNode_content:                         @ the content
    .struct  xmlNode_content + 4 
xmlNode_properties:                      @ properties list
    .struct  xmlNode_properties + 4
xmlNode_nsDef:                           @ namespace definitions on this node 
    .struct  xmlNode_nsDef + 4
xmlNode_psvi:                            @ for type/PSVI informations
    .struct  xmlNode_psvi + 4
xmlNode_line:                            @ line number
    .struct  xmlNode_line + 4
xmlNode_extra:                           @ extra data for XPath/XSLT
    .struct  xmlNode_extra + 4
xmlNode_fin:
/********************************************/
/* structure xmlNodeSet*/
    .struct  0
xmlNodeSet_nodeNr:                       @ number of nodes in the set
    .struct  xmlNodeSet_nodeNr + 4 
xmlNodeSet_nodeMax:                      @ size of the array as allocated 
    .struct  xmlNodeSet_nodeMax + 4 
xmlNodeSet_nodeTab:                      @ array of nodes in no particular order
    .struct  xmlNodeSet_nodeTab + 4 
xmlNodeSet_fin:
/********************************************/
/* structure xmlXPathObject*/
    .struct  0
xmlPathObj_type:                         @
    .struct  xmlPathObj_type + 4 
xmlPathObj_nodesetval:                   @
    .struct  xmlPathObj_nodesetval + 4 
xmlPathObj_boolval:                      @
    .struct  xmlPathObj_boolval + 4 
xmlPathObj_floatval:                     @
    .struct  xmlPathObj_floatval + 4 
xmlPathObj_stringval:                    @
    .struct  xmlPathObj_stringval + 4 
xmlPathObj_user:                         @
    .struct  xmlPathObj_user + 4 
xmlPathObj_index:                        @
    .struct  xmlPathObj_index + 4 
xmlPathObj_user2:                        @
    .struct  xmlPathObj_user2 + 4 
xmlPathObj_index2:                       @
    .struct  xmlPathObj_index2 + 4 



/*********************************/
/* Initialized data              */
/*********************************/
.data
szMessEndpgm:      .asciz "\nNormal end of program.\n" 
szMessDisVal:      .asciz "\nDisplay set values.\n" 
szMessDisArea:     .asciz "\nDisplay area values.\n" 
szFileName:        .asciz "testXml.xml" 
szMessError:       .asciz "Error detected !!!!. \n"


szLibName:         .asciz "name"
szLibPrice:        .asciz "//price"
szLibExtName:      .asciz "//name"
szCarriageReturn:  .asciz "\n"


/*********************************/
/* UnInitialized data            */
/*********************************/
.bss 
.align 4
tbExtract:          .skip 4 * NBMAXELEMENTS      @ result extract area
/*********************************/
/*  code section                 */
/*********************************/
.text
.global main 
main:                                     @ entry of program 
    ldr r0,iAdrszFileName 
    bl xmlParseFile                       @ create doc
    mov r9,r0                             @ doc address
    mov r0,r9                             @ doc
    bl xmlDocGetRootElement               @ get root
    bl xmlFirstElementChild               @ get first section
    bl xmlFirstElementChild               @ get first item
    bl xmlFirstElementChild               @ get first name
    bl xmlNodeGetContent                  @ extract content
    bl affichageMess                      @ for display
    ldr r0,iAdrszCarriageReturn
    bl affichageMess

    ldr r0,iAdrszMessDisVal
    bl affichageMess
    mov r0,r9
    ldr r1,iAdrszLibPrice                  @ extract prices
    bl extractValue
    mov r0,r9
    ldr r1,iAdrszLibExtName                @ extact names
    bl extractValue
    ldr r0,iAdrszMessDisArea
    bl affichageMess
    mov r4,#0                              @ display string result area
    ldr r5,iAdrtbExtract
1:
    ldr r0,[r5,r4,lsl #2]
    cmp r0,#0
    beq 2f
    bl affichageMess
    ldr r0,iAdrszCarriageReturn
    bl affichageMess
    add r4,#1
    b 1b

2:
    mov r0,r9
    bl xmlFreeDoc
    bl xmlCleanupParser
    ldr r0,iAdrszMessEndpgm
    bl affichageMess
    b 100f
99:
    @ error
    ldr r0,iAdrszMessError
    bl affichageMess       
100:                                       @ standard end of the program 
    mov r0, #0                             @ return code
    mov r7, #EXIT                          @ request to exit program
    svc #0                                 @ perform the system call

iAdrszMessError:          .int szMessError
iAdrszMessEndpgm:         .int szMessEndpgm
iAdrszLibName:            .int szLibName
iAdrszLibPrice:           .int szLibPrice
iAdrszCarriageReturn:     .int szCarriageReturn
iAdrszFileName:           .int szFileName
iAdrszLibExtName:         .int szLibExtName
iAdrtbExtract:            .int tbExtract
iAdrszMessDisVal:          .int szMessDisVal
iAdrszMessDisArea:         .int szMessDisArea
/******************************************************************/
/*     extract value of set                                       */ 
/******************************************************************/
/* r0 contains the doc address
/* r1 contains the address of the libel to extract */
extractValue:
    push {r1-r10,lr}                     @ save  registres
    mov r4,r1                            @ save address libel
    mov r9,r0                            @ save doc
    ldr r8,iAdrtbExtract
    bl xmlXPathNewContext                @ create context
    mov r10,r0
    mov r1,r0
    mov r0,r4
    bl xmlXPathEvalExpression
    mov r5,r0
    mov r0,r10
    bl xmlXPathFreeContext               @ free context
    cmp r5,#0
    beq 100f
    ldr r4,[r5,#xmlPathObj_nodesetval]   @ values set
    ldr r6,[r4,#xmlNodeSet_nodeNr]       @ set size
    mov r7,#0                            @ index
    ldr r4,[r4,#xmlNodeSet_nodeTab]      @ area of nods
1:                                       @ start loop 
    ldr r3,[r4,r7,lsl #2]                @ load node
    mov r0,r9
    ldr r1,[r3,#xmlNode_children]        @ load string value
    mov r2,#1
    bl xmlNodeListGetString
    str r0,[r8,r7,lsl #2]                @ store string pointer in area
    bl affichageMess                     @ and display string result
    ldr r0,iAdrszCarriageReturn
    bl affichageMess
    add r7,#1
    cmp r7,r6
    blt 1b
100:
    pop {r1-r10,lr}                      @ restaur registers */ 
    bx lr                                @ return  

/******************************************************************/
/*     display text with size calculation                         */ 
/******************************************************************/
/* r0 contains the address of the message */
affichageMess:
    push {r0,r1,r2,r7,lr}                   @ save  registres
    mov r2,#0                               @ counter length 
1:                                          @ loop length calculation 
    ldrb r1,[r0,r2]                         @ read octet start position + index 
    cmp r1,#0                               @ if 0 its over 
    addne r2,r2,#1                          @ else add 1 in the length 
    bne 1b                                  @ and loop 
                                            @ so here r2 contains the length of the message 
    mov r1,r0                               @ address message in r1 
    mov r0,#STDOUT                          @ code to write to the standard output Linux 
    mov r7, #WRITE                          @ code call system "write" 
    svc #0                                  @ call systeme 
    pop {r0,r1,r2,r7,lr}                    @ restaur registers */ 
    bx lr                                   @ return
Output:
Invisibility Cream

Display set values.
14.50
23.99
4.95
3.56
Invisibility Cream
Levitation Salve
Blork and Freen Instameal
Grob winglets

Display area values.
Invisibility Cream
Levitation Salve
Blork and Freen Instameal
Grob winglets

Normal end of program.

AutoHotkey

With regular expressions 

FileRead, inventory, xmlfile.xml

RegExMatch(inventory, "<item.*?</item>", item1)
MsgBox % item1

pos = 1
While, pos := RegExMatch(inventory, "<price>(.*?)</price>", price, pos + 1)
  MsgBox % price1

While, pos := RegExMatch(inventory, "<name>.*?</name>", name, pos + 1)
  names .= name . "`n"
MsgBox % names
Library: AHK XPath
#Include xpath.ahk

xpath_load(doc, "xmlfile.xml")

; Retrieve the first "item" element
MsgBox % xpath(doc, "/inventory/section[1]/item[1]/text()")

; Perform an action on each "price" element (print it out)
prices := xpath(doc, "/inventory/section/item/price/text()")
Loop, Parse, prices,`,
  reordered .= A_LoopField "`n"
MsgBox % reordered

; Get an array of all the "name" elements
MsgBox % xpath(doc, "/inventory/section/item/name")

Bracmat

{Retrieve the first "item" element}
(   nestML$(get$("doc.xml",X,ML))
  :   ?
      ( inventory
      . ?,? (section.?,? ((item.?):?item) ?) ?
      )
      ?
& out$(toML$!item)
)

{Perform an action on each "price" element (print it out)}
(   nestML$(get$("doc.xml",X,ML))
  :   ?
      ( inventory
      .   ?
        ,   ?
            ( section
            .   ?
              ,   ?
                  ( item
                  .   ?
                    ,   ?
                        ( price
                        .   ?
                          ,   ?price
                            & out$!price
                            & ~
                        )
                        ?
                  )
                  ?
            )
            ?
      )
      ?
|
)

{Get an array of all the "name" elements}
(   :?anArray
  &   nestML$(get$("doc.xml",X,ML))
    :   ?
        ( inventory
        .   ?
          ,   ?
              ( section
              .   ?
                ,   ?
                    ( item
                    .   ?
                      ,   ?
                          ( name
                          .   ?
                            ,   ?name
                              & !anArray !name:?anArray
                              & ~
                          )
                          ?
                    )
                    ?
              )
              ?
        )
        ?
| out$!anArray {Not truly an array, but a list.}
);

C

Library: LibXML

Takes XML document and XPath expression as inputs and prints results, usage is printed if invoked incorrectly. 

#include <libxml/parser.h>
#include <libxml/xpath.h>

xmlDocPtr getdoc (char *docname) {
	xmlDocPtr doc;
	doc = xmlParseFile(docname);

	return doc;
}

xmlXPathObjectPtr getnodeset (xmlDocPtr doc, xmlChar *xpath){
	
	xmlXPathContextPtr context;
	xmlXPathObjectPtr result;

	context = xmlXPathNewContext(doc);

	result = xmlXPathEvalExpression(xpath, context);
	xmlXPathFreeContext(context);

	return result;
}

int main(int argc, char **argv) {

	if (argc <= 2) {
		printf("Usage: %s <XML Document Name> <XPath expression>\n", argv[0]);
		return 0;
	}
	
	char *docname;
	xmlDocPtr doc;
	xmlChar *xpath = (xmlChar*) argv[2];
	xmlNodeSetPtr nodeset;
	xmlXPathObjectPtr result;
	int i;
	xmlChar *keyword;

	docname = argv[1];
	doc = getdoc(docname);
	result = getnodeset (doc, xpath);
	if (result) {
		nodeset = result->nodesetval;
		for (i=0; i < nodeset->nodeNr; i++) {
		xmlNodePtr titleNode = nodeset->nodeTab[i];
		keyword = xmlNodeListGetString(doc, titleNode->xmlChildrenNode, 1);
		printf("Value %d: %s\n",i+1, keyword);
		xmlFree(keyword);
		}
		xmlXPathFreeObject (result);
	}
	xmlFreeDoc(doc);
	xmlCleanupParser();
	return 0;
}

testXML.xml contains the XML mentioned in the task description. Code must be compiled with the correct flags. 

C:\rosettaCode>xPather.exe testXML.xml //price
Value 1: 14.50
Value 2: 23.99
Value 3: 4.95
Value 4: 3.56

C:\rosettaCode>xPather.exe testXML.xml //name
Value 1: Invisibility Cream
Value 2: Levitation Salve
Value 3: Blork and Freen Instameal
Value 4: Grob winglets

C#

XmlReader XReader;
 
// Either read the xml from a string ...
XReader = XmlReader.Create(new StringReader("<inventory title=... </inventory>"));
 
// ... or read it from the file system.
XReader = XmlReader.Create("xmlfile.xml");
 
// Create a XPathDocument object (which implements the IXPathNavigable interface)
// which is optimized for XPath operation. (very fast).
IXPathNavigable XDocument = new XPathDocument(XReader);
 
// Create a Navigator to navigate through the document.
XPathNavigator Nav = XDocument.CreateNavigator();
Nav = Nav.SelectSingleNode("//item");
 
// Move to the first element of the selection. (if available).
if(Nav.MoveToFirst())
{
  Console.WriteLine(Nav.OuterXml); // The outer xml of the first item element.
}
 
// Get an iterator to loop over multiple selected nodes.
XPathNodeIterator Iterator = XDocument.CreateNavigator().Select("//price");
 
while (Iterator.MoveNext())
{
  Console.WriteLine(Iterator.Current.Value);
}
 
Iterator = XDocument.CreateNavigator().Select("//name");
 
// Use a generic list.
List<string> NodesValues = new List<string>();
 
while (Iterator.MoveNext())
{
  NodesValues.Add(Iterator.Current.Value);
}
 
// Convert the generic list to an array and output the count of items.
Console.WriteLine(NodesValues.ToArray().Length);

C++

The following code uses each of the three tasks given to demonstrate a different method of handling the resulting node set from an XPath query.

Library: LibXML
#include <cassert>
#include <cstdlib>
#include <iostream>
#include <stdexcept>
#include <utility>
#include <vector>

#include <libxml/parser.h>
#include <libxml/tree.h>
#include <libxml/xmlerror.h>
#include <libxml/xmlstring.h>
#include <libxml/xmlversion.h>
#include <libxml/xpath.h>

#ifndef LIBXML_XPATH_ENABLED
#   error libxml was not configured with XPath support
#endif

// Because libxml2 is a C library, we need a couple things to make it work
// well with modern C++:
//   1) a ScopeGuard-like type to handle cleanup functions; and
//   2) an exception type that transforms the library's errors.

// ScopeGuard-like type to handle C library cleanup functions.
template <typename F>
class [[nodiscard]] scope_exit
{
public:
    // C++20: Constructor can (and should) be [[nodiscard]].
    /*[[nodiscard]]*/ constexpr explicit scope_exit(F&& f) :
        f_{std::move(f)}
    {}

    ~scope_exit()
    {
        f_();
    }

    // Non-copyable, non-movable.
    scope_exit(scope_exit const&) = delete;
    scope_exit(scope_exit&&) = delete;
    auto operator=(scope_exit const&) -> scope_exit& = delete;
    auto operator=(scope_exit&&) -> scope_exit& = delete;

private:
    F f_;
};

// Exception that gets last libxml2 error.
class libxml_error : public std::runtime_error
{
public:
    libxml_error() : libxml_error(std::string{}) {}

    explicit libxml_error(std::string message) :
        std::runtime_error{make_message_(std::move(message))}
    {}

private:
    static auto make_message_(std::string message) -> std::string
    {
        if (auto const last_error = ::xmlGetLastError(); last_error)
        {
            if (not message.empty())
                message += ": ";
            message += last_error->message;
        }

        return message;
    }
};

auto main() -> int
{
    try
    {
        // Initialize libxml.
        ::xmlInitParser();
        LIBXML_TEST_VERSION
        auto const libxml_cleanup = scope_exit{[] { ::xmlCleanupParser(); }};

        // Load and parse XML document.
        auto const doc = ::xmlParseFile("test.xml");
        if (not doc)
            throw libxml_error{"failed to load document"};
        auto const doc_cleanup = scope_exit{[doc] { ::xmlFreeDoc(doc); }};

        // Create XPath context for document.
        auto const xpath_context = ::xmlXPathNewContext(doc);
        if (not xpath_context)
            throw libxml_error{"failed to create XPath context"};
        auto const xpath_context_cleanup = scope_exit{[xpath_context]
            { ::xmlXPathFreeContext(xpath_context); }};

        // Task 1 ============================================================
        {
            std::cout << "Task 1:\n";

            auto const xpath =
                reinterpret_cast<::xmlChar const*>(u8"//item[1]");

            // Create XPath object (same for every task).
            auto xpath_obj = ::xmlXPathEvalExpression(xpath, xpath_context);
            if (not xpath_obj)
                throw libxml_error{"failed to evaluate XPath"};
            auto const xpath_obj_cleanup = scope_exit{[xpath_obj]
                { ::xmlXPathFreeObject(xpath_obj); }};

            // 'result' a xmlNode* to the desired node, or nullptr if it
            // doesn't exist. If not nullptr, the node is owned by 'doc'.
            auto const result = xmlXPathNodeSetItem(xpath_obj->nodesetval, 0);
            if (result)
                std::cout << '\t' << "node found" << '\n';
            else
                std::cout << '\t' << "node not found" << '\n';
        }

        // Task 2 ============================================================
        {
            std::cout << "Task 2:\n";

            auto const xpath =
                reinterpret_cast<::xmlChar const*>(u8"//price/text()");

            // Create XPath object (same for every task).
            auto xpath_obj = ::xmlXPathEvalExpression(xpath, xpath_context);
            if (not xpath_obj)
                throw libxml_error{"failed to evaluate XPath"};
            auto const xpath_obj_cleanup = scope_exit{[xpath_obj]
                { ::xmlXPathFreeObject(xpath_obj); }};

            // Printing the results.
            auto const count =
                xmlXPathNodeSetGetLength(xpath_obj->nodesetval);
            for (auto i = decltype(count){0}; i < count; ++i)
            {
                auto const node =
                    xmlXPathNodeSetItem(xpath_obj->nodesetval, i);
                assert(node);

                auto const content = XML_GET_CONTENT(node);
                assert(content);

                // Note that reinterpret_cast here is a Bad Idea, because
                // 'content' is UTF-8 encoded, which may or may not be the
                // encoding cout expects. A *PROPER* solution would translate
                // content to the correct encoding (or at least verify that
                // UTF-8 *is* the correct encoding).
                //
                // But this "works" well enough for illustration.
                std::cout << "\n\t" << reinterpret_cast<char const*>(content);
            }

            std::cout << '\n';
        }

        // Task 3 ============================================================
        {
            std::cout << "Task 3:\n";

            auto const xpath =
                reinterpret_cast<::xmlChar const*>(u8"//name");

            // Create XPath object (same for every task).
            auto xpath_obj = ::xmlXPathEvalExpression(xpath, xpath_context);
            if (not xpath_obj)
                throw libxml_error{"failed to evaluate XPath"};
            auto const xpath_obj_cleanup = scope_exit{[xpath_obj]
                { ::xmlXPathFreeObject(xpath_obj); }};

            // 'results' is a vector of pointers to the result nodes. The
            // nodes pointed to are owned by 'doc'.
            auto const results = [ns=xpath_obj->nodesetval]()
            {
                auto v = std::vector<::xmlNode*>{};
                if (ns && ns->nodeTab)
                    v.assign(ns->nodeTab, ns->nodeTab + ns->nodeNr);
                return v;
            }();
            std::cout << '\t' << "set of " << results.size()
                << " node(s) found" << '\n';
        }
    }
    catch (std::exception const& x)
    {
        std::cerr << "ERROR: " << x.what() << '\n';
        return EXIT_FAILURE;
    }
}

Caché ObjectScript

Class XML.Inventory [ Abstract ]
{

XData XMLData
{
<inventory title="OmniCorp Store #45x10^3">
  <section name="health">
    <item upc="123456789" stock="12">
      <name>Invisibility Cream</name>
      <price>14.50</price>
      <description>Makes you invisible</description>
    </item>
    <item upc="445322344" stock="18">
      <name>Levitation Salve</name>
      <price>23.99</price>
      <description>Levitate yourself for up to 3 hours per application</description>
    </item>
  </section>
  <section name="food">
    <item upc="485672034" stock="653">
      <name>Blork and Freen Instameal</name>
      <price>4.95</price>
      <description>A tasty meal in a tablet; just add water</description>
    </item>
    <item upc="132957764" stock="44">
      <name>Grob winglets</name>
      <price>3.56</price>
      <description>Tender winglets of Grob. Just add water</description>
    </item>
  </section>
</inventory>
}

ClassMethod QueryXMLDoc(Output names As %List) As %Status
{
   // get xml stream from the 'XData' block contained in this class
   Set xdata=##class(%Dictionary.CompiledXData).%OpenId($this_"||XMLData",, .sc)
   If $$$ISERR(sc) Quit sc
   Set sc=##class(%XML.XPATH.Document).CreateFromStream(xdata.Data, .xdoc)
   If $$$ISERR(sc) Quit sc
   
   // retrieve the first 'item' element
   Set sc=xdoc.EvaluateExpression("//section[1]", "item[1]", .res)
   
   // perform an action on each 'price' element (print it out)
   Set sc=xdoc.EvaluateExpression("//price", "text()", .res)
   If $$$ISERR(sc) Quit sc
   For i=1:1:res.Count() {
	   If i>1 Write ", "
	   Write res.GetAt(i).Value
   }
   
   // get an array of all the 'name' elements
   Set sc=xdoc.EvaluateExpression("//item", "name", .res)
   If $$$ISERR(sc) Quit sc
   Set key=""
   Do {
	   Set dom=res.GetNext(.key)
	   If '$IsObject(dom) Quit
	   While dom.Read() {
		   If dom.HasValue Set $List(names, key)=dom.Value
	   }
   } While key'=""
   
   // finished
   Quit $$$OK
}

}
Examples:
USER>Do ##class(XML.Inventory).QueryXMLDoc(.list)
14.50, 23.99, 4.95, 3.56
USER>Write $ListToString(list, ", ")             
Invisibility Cream, Levitation Salve, Blork and Freen Instameal, Grob winglets

CoffeeScript

doc = new DOMParser().parseFromString '
    <inventory title="OmniCorp Store #45x10^3">
      <section name="health">
        <item upc="123456789" stock="12">
          <name>Invisibility Cream</name>
          <price>14.50</price>
          <description>Makes you invisible</description>
        </item>
        <item upc="445322344" stock="18">
          <name>Levitation Salve</name>
          <price>23.99</price>
          <description>Levitate yourself for up to 3 hours per application</description>
        </item>
      </section>
      <section name="food">
        <item upc="485672034" stock="653">
          <name>Blork and Freen Instameal</name>
          <price>4.95</price>
          <description>A tasty meal in a tablet; just add water</description>
        </item>
        <item upc="132957764" stock="44">
          <name>Grob winglets</name>
          <price>3.56</price>
          <description>Tender winglets of Grob. Just add water</description>
        </item>
      </section>
    </inventory>
', 'text/xml'

# "doc" is the XML as a Document object. Click expand to see parsing code ⇒ 

# Retrieve the first "item" element 
doc.evaluate('//item', doc, {}, 7, {}).snapshotItem 0

# Perform an action on each "price" element (print it out) 
prices = doc.evaluate "//price", doc, {}, 7, {}
for i in [0...prices.snapshotLength] by 1
    console.log prices.snapshotItem(i).textContent

# Get an array of all the "name" elements 
names = doc.evaluate "//name", doc, {}, 7, {}
names = for i in [0...names.snapshotLength] by 1
    names.snapshotItem i

ColdFusion

<cfsavecontent variable="xmlString">
<inventory
...
</inventory>
</cfsavecontent>
<cfset xml = xmlParse(xmlString)>
<!--- First Task --->
<cfset itemSearch = xmlSearch(xml, "//item")>
<!--- item = the first Item (xml element object) --->
<cfset item = itemSearch[1]>
<!--- Second Task --->
<cfset priceSearch = xmlSearch(xml, "//price")>
<!--- loop and print each price --->
<cfloop from="1" to="#arrayLen(priceSearch)#" index="i">
  #priceSearch[i].xmlText#<br/>
</cfloop>
<!--- Third Task --->
<!--- array of all the name elements --->
<cfset names = xmlSearch(xml, "//name")>
<!--- visualize the results --->
<cfdump var="#variables#">

Common Lisp

Library: plexippus-xpath
Library: cxml
Library: cxml-stp
(dolist (system '(:xpath :cxml-stp :cxml))
  (asdf:oos 'asdf:load-op system))

(defparameter *doc* (cxml:parse-file "xml" (stp:make-builder)))

(xpath:first-node (xpath:evaluate "/inventory/section[1]/item[1]" *doc*))

(xpath:do-node-set (node (xpath:evaluate "/inventory/section/item/price/text()" *doc*))
  (format t "~A~%" (stp:data node)))

(defun node-array (node-set)
  (coerce (xpath:all-nodes node-set) 'vector))

(node-array
 (xpath:evaluate "/inventory/section/item/name" *doc*))

D

It is important to note that the KXML library currently only supports XPath minimally.

Library: KXML
import kxml.xml;
char[]xmlinput =
"<inventory title=\"OmniCorp Store #45x10^3\">
  <section name=\"health\">
    <item upc=\"123456789\" stock=\"12\">
      <name>Invisibility Cream</name>
      <price>14.50</price>
      <description>Makes you invisible</description>
    </item>
    <item upc=\"445322344\" stock=\"18\">
      <name>Levitation Salve</name>
      <price>23.99</price>
      <description>Levitate yourself for up to 3 hours per application</description>
    </item>
  </section>
  <section name=\"food\">
    <item upc=\"485672034\" stock=\"653\">
      <name>Blork and Freen Instameal</name>
      <price>4.95</price>
      <description>A tasty meal in a tablet; just add water</description>
    </item>
    <item upc=\"132957764\" stock=\"44\">
      <name>Grob winglets</name>
      <price>3.56</price>
      <description>Tender winglets of Grob. Just add water</description>
    </item>
  </section>
</inventory>
";
void main() {
        auto root = readDocument(xmlinput);
        auto firstitem = root.parseXPath("inventory/section/item")[0];
        foreach(price;root.parseXPath("inventory/section/item/price")) {
                std.stdio.writefln("%s",price.getCData);
        }
        auto namearray = root.parseXPath("inventory/section/item/name");
}

Delphi

program XMLXPath;

{$APPTYPE CONSOLE}

uses ActiveX, MSXML;

const
  XML =
    '<inventory title="OmniCorp Store #45x10^3">' +
    '  <section name="health">' +
    '    <item upc="123456789" stock="12">' +
    '      <name>Invisibility Cream</name>' +
    '      <price>14.50</price>' +
    '      <description>Makes you invisible</description>' +
    '    </item>' +
    '    <item upc="445322344" stock="18">' +
    '      <name>Levitation Salve</name>' +
    '      <price>23.99</price>' +
    '      <description>Levitate yourself for up to 3 hours per application</description>' +
    '    </item>' +
    '  </section>' +
    '  <section name="food">' +
    '    <item upc="485672034" stock="653">' +
    '      <name>Blork and Freen Instameal</name>' +
    '      <price>4.95</price>' +
    '      <description>A tasty meal in a tablet; just add water</description>' +
    '    </item>' +
    '    <item upc="132957764" stock="44">' +
    '      <name>Grob winglets</name>' +
    '      <price>3.56</price>' +
    '      <description>Tender winglets of Grob. Just add water</description>' +
    '    </item>' +
    '  </section>' +
    '</inventory>';

var
  i: Integer;
  s: string;
  lXMLDoc: IXMLDOMDocument2;
  lNodeList: IXMLDOMNodeList;
  lNode: IXMLDOMNode;
  lItemNames: array of string;
begin
  CoInitialize(nil);
  lXMLDoc := CoDOMDocument.Create;
  lXMLDoc.setProperty('SelectionLanguage', 'XPath');
  lXMLDoc.loadXML(XML);

  Writeln('First item node:');
  lNode := lXMLDoc.selectNodes('//item')[0];
  Writeln(lNode.xml);
  Writeln('');

  lNodeList := lXMLDoc.selectNodes('//price');
  for i := 0 to lNodeList.length - 1 do
    Writeln('Price = ' + lNodeList[i].text);
  Writeln('');

  lNodeList := lXMLDoc.selectNodes('//item/name');
  SetLength(lItemNames, lNodeList.length);
  for i := 0 to lNodeList.length - 1 do
    lItemNames[i] := lNodeList[i].text;
  for s in lItemNames do
    Writeln('Item name = ' + s);
end.

Output: 

First item node:
<item upc="123456789" stock="12">
	<name>Invisibility Cream</name>
	<price>14.50</price>
	<description>Makes you invisible</description>
</item>

Price = 14.50
Price = 23.99
Price = 4.95
Price = 3.56

Item name = Invisibility Cream
Item name = Levitation Salve
Item name = Blork and Freen Instameal
Item name = Grob winglets

E

Library: E-XML

(currently a very early work in progress/draft library; design comments welcome) 

? def xml__quasiParser := <import:org.switchb.e.xml.makeXMLQuasiParser>()
> def xpath__quasiParser := xml__quasiParser.xPathQuasiParser()
> null

? def doc := xml`<inventory title="OmniCorp Store #45x10^3">
>   <section name="health">
>     <item upc="123456789" stock="12">
>       <name>Invisibility Cream</name>
>       <price>14.50</price>
>       <description>Makes you invisible</description>
>     </item>
>     <item upc="445322344" stock="18">
>       <name>Levitation Salve</name>
>       <price>23.99</price>
>       <description>Levitate yourself for up to 3 hours per application</description>n>
>     </item>
>   </section>
>   <section name="food">
>     <item upc="485672034" stock="653">
>       <name>Blork and Freen Instameal</name>
>       <price>4.95</price>
>       <description>A tasty meal in a tablet; just add water</description>
>     </item>
>     <item upc="132957764" stock="44">
>       <name>Grob winglets</name>
>       <price>3.56</price>
>       <description>Tender winglets of Grob. Just add water</description>
>     </item>
>   </section>
> </inventory>`
# value: xml`...`

? doc[xpath`inventory/section/item`][0]
# value: xml`<item stock="12" upc="123456789">
#              <name>Invisibility Cream</name>
#              <price>14.50</price>
#              <description>Makes you invisible</description>
#            </item>`

? for price in doc[xpath`inventory/section/item/price/text()`] { println(price :String) }
14.50
23.99
4.95
3.56

? doc[xpath`inventory/section/item/name`]
# value: [xml`<name>Invisibility Cream</name>`,
#         xml`<name>Levitation Salve</name>`,
#         xml`<name>Blork and Freen Instameal</name>`,
#         xml`<name>Grob winglets</name>`]

Erlang

Library: xmerl
-module(xml_xpath).
-include_lib("xmerl/include/xmerl.hrl").

-export([main/0]).

main() -> 
   XMLDocument = 
      "<inventory title=\"OmniCorp Store #45x10^3\">
        <section name=\"health\">
          <item upc=\"123456789\" stock=\"12\">
            <name>Invisibility Cream</name>
            <price>14.50</price>
            <description>Makes you invisible</description>
          </item>
          <item upc=\"445322344\" stock=\"18\">
            <name>Levitation Salve</name>
            <price>23.99</price>
            <description>Levitate yourself for up to 3 hours per application</description>
          </item>
        </section>
        <section name=\"food\">
          <item upc=\"485672034\" stock=\"653\">
            <name>Blork and Freen Instameal</name>
            <price>4.95</price>
            <description>A tasty meal in a tablet; just add water</description>
          </item>
          <item upc=\"132957764\" stock=\"44\">
            <name>Grob winglets</name>
            <price>3.56</price>
            <description>Tender winglets of Grob. Just add water</description>
          </item>
        </section>
      </inventory>",
   {Document,_} = xmerl_scan:string(XMLDocument),

   io:format("First item:\n~s\n",
      [lists:flatten(
         xmerl:export_simple(
            [hd(xmerl_xpath:string("//item[1]", Document))], 
            xmerl_xml, [{prolog, ""}]))]),
   
   io:format("Prices:\n"),
   [ io:format("~s\n",[Content#xmlText.value]) 
      || #xmlElement{content = [Content|_]} <- xmerl_xpath:string("//price", Document)],

   io:format("Names:\n"),
   [ Content#xmlText.value 
      || #xmlElement{content = [Content|_]} <- xmerl_xpath:string("//name", Document)].

Output:

First item:
<item upc="123456789" stock="12">
            <name>Invisibility Cream</name>
            <price>14.50</price>
            <description>Makes you invisible</description>
          </item>
Prices:
14.50
23.99
4.95
3.56
Names:
["Invisibility Cream","Levitation Salve",
 "Blork and Freen Instameal","Grob winglets"]

FreeBASIC

Dim As String XML, item, price, nombre
Dim As Integer P1, P2

'' Read the XML file
Open "test3.xml" For Input As #1
XML = Input(Lof(1), #1)
Close #1

'' Find the first 'item' element
P1 = Instr(XML, "<item ")
P2 = Instr(XML, "</item>")
item = Mid(XML, P1, P2-P1+7)
Print "The first 'item' element is:"
Print item

'' Find all 'price' elements
Print "The 'prices' are:"
P1 = 1
Do
    P1 = Instr(P1, XML, "<price>")
    If P1 = 0 Then Exit Do
    P2 = Instr(P1, XML, "</price>")
    price = Mid(XML, P1+7, P2-P1-7)
    Print price
    P1 = P2 + 1
Loop

'' Find all 'nombre' elements
Print !"\nThe 'names' are:"
P1 = 1
Do
    P1 = Instr(P1, XML, "<name>")
    If P1 = 0 Then Exit Do
    P2 = Instr(P1, XML, "</name>")
    nombre = Mid(XML, P1+6, P2-P1-6)
    Print nombre
    P1 = P2 + 1
Loop

Sleep

F#

open System.IO
open System.Xml.XPath

let xml = new StringReader("""
<inventory title="OmniCorp Store #45x10^3">
  <section name="health">
    <item upc="123456789" stock="12">
      <name>Invisibility Cream</name>
      <price>14.50</price>
      <description>Makes you invisible</description>
    </item>
    <item upc="445322344" stock="18">
      <name>Levitation Salve</name>
      <price>23.99</price>
      <description>Levitate yourself for up to 3 hours per application</description>
    </item>
  </section>
  <section name="food">
    <item upc="485672034" stock="653">
      <name>Blork and Freen Instameal</name>
      <price>4.95</price>
      <description>A tasty meal in a tablet; just add water</description>
    </item>
    <item upc="132957764" stock="44">
      <name>Grob winglets</name>
      <price>3.56</price>
      <description>Tender winglets of Grob. Just add water</description>
    </item>
  </section>
</inventory>
""")

let nav = XPathDocument(xml).CreateNavigator()

// first "item"; throws if none exists
let item = nav.SelectSingleNode(@"//item[1]")

// apply a operation (print text value) to all price elements
for price in nav.Select(@"//price") do
    printfn "%s" (price.ToString())

// array of all name elements
let names = seq { for name in nav.Select(@"//name") do yield name } |> Seq.toArray

Factor

Library: xml
Library: xml.data
Library: xml.traversal
! Get first item element
"""<inventory title="OmniCorp Store #45x10^3">
  <section name="health">
    <item upc="123456789" stock="12">
      <name>Invisibility Cream</name>
      <price>14.50</price>
      <description>Makes you invisible</description>
    </item>
    <item upc="445322344" stock="18">
      <name>Levitation Salve</name>
      <price>23.99</price>
      <description>Levitate yourself for up to 3 hours per application</description>
    </item>
  </section>
  <section name="food">
    <item upc="485672034" stock="653">
      <name>Blork and Freen Instameal</name>
      <price>4.95</price>
      <description>A tasty meal in a tablet; just add water</description>
    </item>
    <item upc="132957764" stock="44">
      <name>Grob winglets</name>
      <price>3.56</price>
      <description>Tender winglets of Grob. Just add water</description>
    </item>
  </section>
</inventory>""" string>xml "item" deep-tag-named

! Print out prices
"""<inventory title="OmniCorp Store #45x10^3">
  <section name="health">
    <item upc="123456789" stock="12">
      <name>Invisibility Cream</name>
      <price>14.50</price>
      <description>Makes you invisible</description>
    </item>
    <item upc="445322344" stock="18">
      <name>Levitation Salve</name>
      <price>23.99</price>
      <description>Levitate yourself for up to 3 hours per application</description>
    </item>
  </section>
  <section name="food">
    <item upc="485672034" stock="653">
      <name>Blork and Freen Instameal</name>
      <price>4.95</price>
      <description>A tasty meal in a tablet; just add water</description>
    </item>
    <item upc="132957764" stock="44">
      <name>Grob winglets</name>
      <price>3.56</price>
      <description>Tender winglets of Grob. Just add water</description>
    </item>
  </section>
</inventory>""" string>xml "price" deep-tags-named [ children>> first ] map

! Array of all name elements
"""<inventory title="OmniCorp Store #45x10^3">
  <section name="health">
    <item upc="123456789" stock="12">
      <name>Invisibility Cream</name>
      <price>14.50</price>
      <description>Makes you invisible</description>
    </item>
    <item upc="445322344" stock="18">
      <name>Levitation Salve</name>
      <price>23.99</price>
      <description>Levitate yourself for up to 3 hours per application</description>
    </item>
  </section>
  <section name="food">
    <item upc="485672034" stock="653">
      <name>Blork and Freen Instameal</name>
      <price>4.95</price>
      <description>A tasty meal in a tablet; just add water</description>
    </item>
    <item upc="132957764" stock="44">
      <name>Grob winglets</name>
      <price>3.56</price>
      <description>Tender winglets of Grob. Just add water</description>
    </item>
  </section>
</inventory>""" string>xml "name" deep-tags-named

Gastona

The example uses the command XMELON which parses a XML file of any schema and stores its contents into db tables. This parser is described in the article XMeLon-Schema 

#javaj#

   <frames> oSal, XML Path sample, 300, 400
         
#data#

   <xml>
      //<inventory title="OmniCorp Store #45x10^3">
      //  <section name="health">
      //    <item upc="123456789" stock="12">
      //      <name>Invisibility Cream</name>
      //      <price>14.50</price>
      //      <description>Makes you invisible</description>
      //    </item>
      //    <item upc="445322344" stock="18">
      //      <name>Levitation Salve</name>
      //      <price>23.99</price>
      //      <description>Levitate yourself for up to 3 hours per application</description>
      //    </item>
      //  </section>
      //  <section name="food">
      //    <item upc="485672034" stock="653">
      //      <name>Blork and Freen Instameal</name>
      //      <price>4.95</price>
      //      <description>A tasty meal in a tablet; just add water</description>
      //    </item>
      //    <item upc="132957764" stock="44">
      //      <name>Grob winglets</name>
      //      <price>3.56</price>
      //      <description>Tender winglets of Grob. Just add water</description>
      //    </item>
      //  </section>
      //</inventory>
   
   <DEEP_SQL_XML>
      DEEP DB, SELECT, xmelon_data
             ,, path pathStr
             ,, tag tagStr
             ,, patCnt
             ,, dataPlace
             ,, value
   
#listix#

   <main>
      //parsing xml data ...
      GEN, :mem datos, xml
      XMELON, FILE2DB, :mem datos
      //
      //first item ...
      //
      //
      LOOP, SQL,, //SELECT patCnt AS patITEM1 FROM (@<DEEP_SQL_XML>) WHERE path_pathStr == '/inventory/section/item' LIMIT 1
          ,HEAD, //<item
          ,, LOOP, SQL,, //SELECT * FROM (@<DEEP_SQL_XML>) WHERE patCnt == @<patITEM1> AND dataPlace == 'A'
          ,,     , LINK, ""
          ,,     ,, // @<tag_tagStr>="@<value>"
          ,, //>
          ,, //
          ,, LOOP, SQL,, //SELECT * FROM (@<DEEP_SQL_XML>) WHERE patCnt == @<patITEM1> AND dataPlace != 'A'
          ,,     ,, //    <@<tag_tagStr>>@<value></@<tag_tagStr>>
          ,TAIL, //
          ,TAIL, //</item>
      //
      //
      //report prices ...
      //
      LOOP, SQL,, //SELECT value FROM (@<DEEP_SQL_XML>) WHERE tag_tagStr == 'price'
          , LINK, ", "
          ,, @<value>
      //
      //put names into a variable
      //
      VAR=, tabnames, "name"
      LOOP, SQL,, //SELECT value FROM (@<DEEP_SQL_XML>) WHERE tag_tagStr == 'name'
          , LINK, ""
          ,, VAR+, tabnames, @<value>
      DUMP, data,, tabnames
Output:
parsing xml data ...
first item ...

<item upc="123456789" stock="12">
    <name>Invisibility Cream</name>
    <price>14.50</price>
    <description>Makes you invisible</description>
</item>

report prices ...
14.50, 23.99, 4.95, 3.56
names into a variable
#data#

   <tabnames>
      //name
      //health
      //Invisibility Cream
      //Levitation Salve
      //food
      //Blork and Freen Instameal
      //Grob winglets

Go

Using the standard encoding/xml package: 

package main

import (
	"encoding/xml"
	"fmt"
	"log"
	"os"
)

type Inventory struct {
	XMLName  xml.Name `xml:"inventory"`
	Title    string   `xml:"title,attr"`
	Sections []struct {
		XMLName xml.Name `xml:"section"`
		Name    string   `xml:"name,attr"`
		Items   []struct {
			XMLName     xml.Name `xml:"item"`
			Name        string   `xml:"name"`
			UPC         string   `xml:"upc,attr"`
			Stock       int      `xml:"stock,attr"`
			Price       float64  `xml:"price"`
			Description string   `xml:"description"`
		} `xml:"item"`
	} `xml:"section"`
}

// To simplify main's error handling
func printXML(s string, v interface{}) {
	fmt.Println(s)
	b, err := xml.MarshalIndent(v, "", "\t")
	if err != nil {
		log.Fatal(err)
	}
	fmt.Println(string(b))
	fmt.Println()
}

func main() {
	fmt.Println("Reading XML from standard input...")

	var inv Inventory
	dec := xml.NewDecoder(os.Stdin)
	if err := dec.Decode(&inv); err != nil {
		log.Fatal(err)
	}

	// At this point, inv is Go struct with all the fields filled
	// in from the XML data. Well-formed XML input that doesn't
	// match the specification of the fields in the Go struct are
	// discarded without error.

	// We can reformat the parts we parsed:
	//printXML("Got:", inv)

	// 1. Retrieve first item:
	item := inv.Sections[0].Items[0]
	fmt.Println("item variable:", item)
	printXML("As XML:", item)

	// 2. Action on each price:
	fmt.Println("Prices:")
	var totalValue float64
	for _, s := range inv.Sections {
		for _, i := range s.Items {
			fmt.Println(i.Price)
			totalValue += i.Price * float64(i.Stock)
		}
	}
	fmt.Println("Total inventory value:", totalValue)
	fmt.Println()

	// 3. Slice of all the names:
	var names []string
	for _, s := range inv.Sections {
		for _, i := range s.Items {
			names = append(names, i.Name)
		}
	}
	fmt.Printf("names: %q\n", names)
}
Output:
Reading XML from standard input...
item variable: {{ item} Invisibility Cream 123456789 12 14.5 Makes you invisible}
As XML:
<item upc="123456789" stock="12">
	<name>Invisibility Cream</name>
	<price>14.5</price>
	<description>Makes you invisible</description>
</item>

Prices:
14.5
23.99
4.95
3.56
Total inventory value: 3994.81

names: ["Invisibility Cream" "Levitation Salve" "Blork and Freen Instameal" "Grob winglets"]
Library: xmlpath
package main

import (
    "fmt"
    "os"

    "launchpad.net/xmlpath"
)

func main() {
    f, err := os.Open("test3.xml")
    if err != nil {
        fmt.Println(err)
        return
    }
    n, err := xmlpath.Parse(f)
    f.Close()
    if err != nil {
        fmt.Println(err)
        return
    }
    q1 := xmlpath.MustCompile("//item")
    if _, ok := q1.String(n); !ok {
        fmt.Println("no item")
    }
    q2 := xmlpath.MustCompile("//price")
    for it := q2.Iter(n); it.Next(); {
        fmt.Println(it.Node())
    }
    q3 := xmlpath.MustCompile("//name")
    names := []*xmlpath.Node{}
    for it := q3.Iter(n); it.Next(); {
        names = append(names, it.Node())
    }
    if len(names) == 0 {
        fmt.Println("no names")
    }
}
Output:
14.50
23.99
4.95
3.56

Groovy

def inventory = new XmlSlurper().parseText("<inventory...")    //optionally parseText(new File("inv.xml").text)
def firstItem = inventory.section.item[0]                      //1. first item
inventory.section.item.price.each { println it }               //2. print each price
def allNamesArray = inventory.section.item.name.collect {it}   //3. collect item names into an array

Haskell

import Data.List
import Control.Arrow
import Control.Monad

takeWhileIncl           :: (a -> Bool) -> [a] -> [a]
takeWhileIncl _ []      =  []
takeWhileIncl p (x:xs)
            | p x       =  x : takeWhileIncl p xs
            | otherwise =  [x] 

getmultiLineItem n = takeWhileIncl(not.isInfixOf ("</" ++ n)). dropWhile(not.isInfixOf ('<': n))
getsingleLineItems n = map (takeWhile(/='<'). drop 1. dropWhile(/='>')). filter (isInfixOf ('<': n))

main = do
  xml <- readFile "./Rosetta/xmlpath.xml"
  let xmlText = lines xml
      
  putStrLn "\n== First item ==\n"
  mapM_ putStrLn $ head $ unfoldr (Just. liftM2 (id &&&) (\\) (getmultiLineItem "item")) xmlText
  
  putStrLn "\n== Prices ==\n"
  mapM_ putStrLn $ getsingleLineItems "price" xmlText
  
  putStrLn "\n== Names ==\n"
  print $ getsingleLineItems "name" xmlText

Using the Haskell XML Toolkit (HXT): 

{-# LANGUAGE Arrows #-}
import Text.XML.HXT.Arrow
{- For HXT version >= 9.0, use instead:
import Text.XML.HXT.Core
-}

deepElem name = deep (isElem >>> hasName name)

process = proc doc -> do
  item <- single (deepElem "item") -< doc
  _ <- listA (arrIO print <<< deepElem "price") -< doc
  names <- listA (deepElem "name") -< doc
  returnA -< (item, names)
  
main = do
  [(item, names)] <- runX (readDocument [] "xmlpath.xml" >>> process)
  print item
  print names

HicEst

CHARACTER xml*1000, output*1000
  READ(ClipBoard) xml

  EDIT(Text=xml, Right='<item', Right=5, GetPosition=a, Right='</item>', Left, GetPosition=z)
  WRITE(Text=output) xml( a : z), $CRLF

  i = 1
1 EDIT(Text=xml, SetPosition=i, SePaRators='<>', Right='<price>', Word=1, Parse=price, GetPosition=i, ERror=99)
  IF(i > 0) THEN
      WRITE(Text=output, APPend)  'Price element = ', price, $CRLF
      GOTO 1  !  HicEst does not have a "WHILE"
  ENDIF

  EDIT(Text=xml, SPR='<>', R='<name>', W=1, WordEnd=$CR, APpendTo=output, DO=999)
  WRITE(ClipBoard) TRIM(output)
 upc="123456789" stock="12">
      <name>Invisibility Cream</name>
      <price>14.50</price>
      <description>Makes you invisible</description>
    
Price element = 14.50
Price element = 23.99
Price element = 4.95
Price element = 3.56
Invisibility Cream
 Levitation Salve
 Blork and Freen Instameal
 Grob winglets

Java

import java.io.StringReader;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.InputSource;

public class XMLParser {
	final static String xmlStr = 
			  "<inventory title=\"OmniCorp Store #45x10^3\">"
			+ "  <section name=\"health\">"
			+ "    <item upc=\"123456789\" stock=\"12\">"
			+ "      <name>Invisibility Cream</name>"
			+ "      <price>14.50</price>"
			+ "      <description>Makes you invisible</description>"
			+ "    </item>"
			+ "    <item upc=\"445322344\" stock=\"18\">"
			+ "      <name>Levitation Salve</name>"
			+ "      <price>23.99</price>"
			+ "      <description>Levitate yourself for up to 3 hours per application</description>"
			+ "    </item>"
			+ "  </section>"
			+ "  <section name=\"food\">"
			+ "    <item upc=\"485672034\" stock=\"653\">"
			+ "      <name>Blork and Freen Instameal</name>"
			+ "      <price>4.95</price>"
			+ "      <description>A tasty meal in a tablet; just add water</description>"
			+ "    </item>"
			+ "    <item upc=\"132957764\" stock=\"44\">"
			+ "      <name>Grob winglets</name>"
			+ "      <price>3.56</price>"
			+ "      <description>Tender winglets of Grob. Just add priwater</description>"
			+ "    </item>"
			+ "  </section>" 
			+ "</inventory>";

	public static void main(String[] args) {
		try {
			Document doc = DocumentBuilderFactory.newInstance()
					.newDocumentBuilder()
					.parse(new InputSource(new StringReader(xmlStr)));
			XPath xpath = XPathFactory.newInstance().newXPath();
			// 1
			System.out.println(((Node) xpath.evaluate(
					"/inventory/section/item[1]", doc, XPathConstants.NODE))
					.getAttributes().getNamedItem("upc"));
			// 2, 3
			NodeList nodes = (NodeList) xpath.evaluate(
					"/inventory/section/item/price", doc,
					XPathConstants.NODESET);
			for (int i = 0; i < nodes.getLength(); i++)
				System.out.println(nodes.item(i).getTextContent());
		} catch (Exception e) {
			System.out.println("Error ocurred while parsing XML.");
		}
	}
}

JavaScript

Works with: Firefox version 2.0
//create XMLDocument object from file
var xhr = new XMLHttpRequest();
xhr.open('GET', 'file.xml', false);
xhr.send(null);
var doc = xhr.responseXML;

//get first <item> element
var firstItem = doc.evaluate( '//item[1]', doc, null, XPathResult.FIRST_ORDERED_NODE_TYPE, null ).singleNodeValue;
alert( firstItem.textContent );

//output contents of <price> elements
var prices = doc.evaluate( '//price', doc, null, XPathResult.ANY_TYPE, null );
for( var price = prices.iterateNext(); price != null; price = prices.iterateNext() ) {
  alert( price.textContent );
}

//add <name> elements to array
var names = doc.evaluate( '//name', doc, null, XPathResult.ANY_TYPE, null);
var namesArray = [];
for( var name = names.iterateNext(); name != null; name = names.iterateNext() ) {
  namesArray.push( name );
}
alert( namesArray );

Although some browsers support XPath, working with XML is much easier with E4X. 

//create XML object from file
var xhr = new XMLHttpRequest();
xhr.open('GET', 'file.xml', false);
xhr.send(null);
var doc = new XML(xhr.responseText);

//get first <item> element
var firstItem = doc..item[0];
alert( firstItem );

//output contents of <price> elements
for each( var price in doc..price ) {
  alert( price );
}

//add <name> elements to array
var names = [];
for each( var name in doc..name ) {
  names.push( name );
}
alert( names );

Julia

Uses the LibExpat module for XML pathing. The exercise description is very vague about output format, so this is varied in the solution below. The first test prints the raw XML node, and the second and third are further processed. 

using LibExpat

xdoc = raw"""<inventory title="OmniCorp Store #45x10^3">
  <section name="health">
    <item upc="123456789" stock="12">
      <name>Invisibility Cream</name>
      <price>14.50</price>
      <description>Makes you invisible</description>
    </item>
    <item upc="445322344" stock="18">
      <name>Levitation Salve</name>
      <price>23.99</price>
      <description>Levitate yourself for up to 3 hours per application</description>
    </item>
  </section>
  <section name="food">
    <item upc="485672034" stock="653">
      <name>Blork and Freen Instameal</name>
      <price>4.95</price>
      <description>A tasty meal in a tablet; just add water</description>
    </item>
    <item upc="132957764" stock="44">
      <name>Grob winglets</name>
      <price>3.56</price>
      <description>Tender winglets of Grob. Just add water</description>
    </item>
  </section>
</inventory>
"""

debracket(s) = replace(s, r".+\>(.+)\<.+" => s"\1") 

etree = xp_parse(xdoc)
firstshow = LibExpat.find(etree, "//item")[1]
println("The first item's node XML entry is:\n", firstshow, "\n\n")

prices = LibExpat.find(etree, "//price")
println("Prices:")
for p in prices
    println("\t", debracket(string(p)))
end
println("\n")

namearray = LibExpat.find(etree, "//name")
println("Array of names of items:\n\t", map(s -> debracket(string(s)), namearray))
Output:


The first item's node XML entry is:
   <item upc="123456789" stock="12">
     <name>Invisibility Cream</name>
     <price>14.50</price>
     <description>Makes you invisible</description>
   </item>








Prices:
       14.50
       23.99
       4.95
       3.56








Array of names of items:
       ["Invisibility Cream", "Levitation Salve", "Blork and Freen Instameal", "Grob winglets"]

Kotlin

// version 1.1.3

import javax.xml.parsers.DocumentBuilderFactory
import org.xml.sax.InputSource
import java.io.StringReader
import javax.xml.xpath.XPathFactory
import javax.xml.xpath.XPathConstants
import org.w3c.dom.Node
import org.w3c.dom.NodeList

val xml = 
"""
<inventory title="OmniCorp Store #45x10^3">
  <section name="health">
    <item upc="123456789" stock="12">
      <name>Invisibility Cream</name>
      <price>14.50</price>
      <description>Makes you invisible</description>
    </item>
    <item upc="445322344" stock="18">
      <name>Levitation Salve</name>
      <price>23.99</price>
      <description>Levitate yourself for up to 3 hours per application</description>
    </item>
  </section>
  <section name="food">
    <item upc="485672034" stock="653">
      <name>Blork and Freen Instameal</name>
      <price>4.95</price>
      <description>A tasty meal in a tablet; just add water</description>
    </item>
    <item upc="132957764" stock="44">
      <name>Grob winglets</name>
      <price>3.56</price>
      <description>Tender winglets of Grob. Just add water</description>
    </item>
  </section>
</inventory>
"""

fun main(args: Array<String>) {
    val dbFactory = DocumentBuilderFactory.newInstance()
    val dBuilder  = dbFactory.newDocumentBuilder()
    val xmlInput = InputSource(StringReader(xml))
    val doc = dBuilder.parse(xmlInput)
    val xpFactory = XPathFactory.newInstance()
    val xPath = xpFactory.newXPath()

    val qNode = xPath.evaluate("/inventory/section/item[1]", doc, XPathConstants.NODE) as Node
    val upc = qNode.attributes.getNamedItem("upc")
    val stock = qNode.attributes.getNamedItem("stock")
    println("For the first item :  upc = ${upc.textContent} and stock = ${stock.textContent}")

    val qNodes = xPath.evaluate("/inventory/section/item/price", doc, XPathConstants.NODESET) as NodeList
    print("\nThe prices of each item are : ")
    for (i in 0 until qNodes.length) print("${qNodes.item(i).textContent}  ")
    println()

    val qNodes2 = xPath.evaluate("/inventory/section/item/name", doc, XPathConstants.NODESET) as NodeList
    val names = Array<String>(qNodes2.length) { qNodes2.item(it).textContent }
    println("\nThe names of each item are as follows :")
    println("  ${names.joinToString("\n  ")}")
}
Output:
For the first item :  upc = 123456789 and stock = 12

The prices of each item are : 14.50  23.99  4.95  3.56  

The names of each item are as follows :
  Invisibility Cream
  Levitation Salve
  Blork and Freen Instameal
  Grob winglets

Ksh

#!/bin/ksh

# Perform XPath queries on a XML Document

#	# Variables:
#
typeset -T Xml_t=(
	typeset -h		'UPC'			upc
	typeset -i -h	'num in stock'	stock=0
	typeset -h		'name'			name
	typeset -F2 -h	'price'			price
	typeset -h		'description'	description

	function init_item {
		typeset key ; key="$1"
		typeset val ; val="${2%\<\/${key}*}"

		case ${key} in
			upc)			_.upc="${val//@(\D)/}"
				;;
			stock)			_.stock="${val//@(\D)/}"
				;;
			name)			_.name="${val%\<\/${key}*}"
				;;
			price)			_.price="${val}"
				;;
			description)	_.description=$(echo ${val})
				;;
		esac
	}

	function prt_item {
		print "upc= ${_.upc}"
		print "stock= ${_.stock}"
		print "name= ${_.name}"
		print "price= ${_.price}"
		print "description= ${_.description}"
	}
)

#	# Functions:
#


 ######
# main #
 ######
integer i=0
typeset -a Item_t

buff=$(< xmldoc)	# read xmldoc
item=${buff%%'</item>'*} ; buff=${.sh.match}

while [[ -n ${item} ]]; do
	Xml_t Item_t[i]
	item=${item#*'<item'} ; item=$(echo ${item})
	for word in ${item}; do
		if [[ ${word} == *=* ]]; then
			Item_t[i].init_item ${word%\=*} ${word#*\=}
		else
			if [[ ${word} == \<* ]]; then		# Beginning
				key=${word%%\>*} ; key=${key#*\<}
				val=${word#*\>}
			fi

			[[ ${word} != \<* && ${word} != *\> ]] && val+=" ${word} "

			if [[ ${word} == *\> ]]; then		# End
				val+=" ${word%\<${key}\>*}"
				Item_t[i].init_item "${key}" "${val}"
			fi
		fi
	done
	(( i++ ))
	item=${buff#*'</item>'} ; item=${item%%'</item>'*} ; buff=${.sh.match}
done

print "First Item element:"
Item_t[0].prt_item

typeset -a names
printf "\nList of prices:\n"
for ((i=0; i<${#Item_t[*]}-1; i++)); do
	print ${Item_t[i].price}
	names[i]=${Item_t[i].name}
done

printf "\nArray of names:\n"
for (( i=0; i<${#names[*]}; i++)); do
	print "names[$i] = ${names[i]}"
done
Output:


First Item element:
upc= 123456789
stock= 12
name= Invisibility Cream
price= 14.50
description= Makes you invisible

List of prices:
14.50
23.99
4.95
3.56

Array of names:
names[0] = Invisibility Cream
names[1] = Levitation Salve
names[2] = Blork and  Freen  Instameal


names[3] = Grob winglets

Lasso

Lasso has built in support for both XML handling and Xpaths 

// makes extracting attribute values easier
define xml_attrmap(in::xml_namedNodeMap_attr) => {
	local(out = map)
	with attr in #in
		do #out->insert(#attr->name = #attr->value)
	return #out
}

local(
	text = '<inventory title="OmniCorp Store #45x10^3">
  <section name="health">
    <item upc="123456789" stock="12">
      <name>Invisibility Cream</name>
      <price>14.50</price>
      <description>Makes you invisible</description>
    </item>
    <item upc="445322344" stock="18">
      <name>Levitation Salve</name>
      <price>23.99</price>
      <description>Levitate yourself for up to 3 hours per application</description>
    </item>
  </section>
  <section name="food">
    <item upc="485672034" stock="653">
      <name>Blork and Freen Instameal</name>
      <price>4.95</price>
      <description>A tasty meal in a tablet; just add water</description>
    </item>
    <item upc="132957764" stock="44">
      <name>Grob winglets</name>
      <price>3.56</price>
      <description>Tender winglets of Grob. Just add water</description>
    </item>
  </section>
</inventory>
',
xml = xml(#text)
)

local(
	items		= #xml -> extract('//item'),
	firstitem	= #items -> first,
	itemattr	= xml_attrmap(#firstitem -> attributes),
	newprices	= array
)

'<strong>First item:</strong><br />
UPC: '
#itemattr -> find('upc')
' (stock: '
#itemattr -> find('stock')
')<br />'
#firstitem -> extractone('name') -> nodevalue
' ['
#firstitem -> extractone('price') -> nodevalue
'] ('
#firstitem -> extractone('description') -> nodevalue
')<br /><br />'

with item in #items
let name = #item -> extractone('name') -> nodevalue
let price = #item -> extractone('price') -> nodevalue
do {
	#newprices -> insert(#name + ': ' + (decimal(#price) * 1.10) -> asstring(-precision = 2) + ' (' + #price + ')')
}
'<strong>Adjusted prices:</strong><br />'
#newprices -> join('<br />')
'<br /><br />'
'<strong>Array with all names:</strong><br />'
#xml -> extract('//name') -> asstaticarray

Output: 

First item:
UPC: 123456789 (stock: 12)
Invisibility Cream [14.50] (Makes you invisible)

Adjusted prices:
Invisibility Cream: 15.95 (14.50)
Levitation Salve: 26.39 (23.99)
Blork and Freen Instameal: 5.45 (4.95)
Grob winglets: 3.92 (3.56)

Array with all names:
staticarray(Invisibility Cream, Levitation Salve, Blork and Freen Instameal, Grob winglets)

LiveCode

Copy the xml in this task into a text field called "FieldXML" 

put revXMLCreateTree(fld "FieldXML",true,true,false) into xmltree

// task 1
put revXMLEvaluateXPath(xmltree,"//item[1]") into nodepath
put revXMLText(xmltree,nodepath,true)

// task 2
put revXMLDataFromXPathQuery(xmltree,"//item/price",,comma)

// task 3
put revXMLDataFromXPathQuery(xmltree,"//name") into namenodes
filter namenodes without empty
split namenodes using cr
put namenodes is an array

Lua

Requires LuaExpat 

require 'lxp'
data = [[<inventory title="OmniCorp Store #45x10^3">
  <section name="health">
    <item upc="123456789" stock="12">
      <name>Invisibility Cream</name>
      <price>14.50</price>
      <description>Makes you invisible</description>
    </item>
    <item upc="445322344" stock="18">
      <name>Levitation Salve</name>
      <price>23.99</price>
      <description>Levitate yourself for up to 3 hours per application</description>
    </item>
  </section>
  <section name="food">
    <item upc="485672034" stock="653">
      <name>Blork and Freen Instameal</name>
      <price>4.95</price>
      <description>A tasty meal in a tablet; just add water</description>
    </item>
    <item upc="132957764" stock="44">
      <name>Grob winglets</name>
      <price>3.56</price>
      <description>Tender winglets of Grob. Just add water</description>
    </item>
  </section>
</inventory>]]
local first = true
local names, prices = {}, {}
p = lxp.new({StartElement = function (parser, name)
	local a, b, c = parser:pos() --line, offset, pos
	if name == 'item' and first then 
		print(data:match('.-</item>', c - b + 1))
		first = false
	end
	if name == 'name' then names[#names+1] = data:match('>(.-)<', c) end
	if name == 'price' then prices[#prices+1] = data:match('>(.-)<', c) end
end})

p:parse(data)
p:close()

print('Name: ', table.concat(names, ', '))
print('Price: ', table.concat(prices, ', '))

Output:

    <item upc="123456789" stock="12">
      <name>Invisibility Cream</name>
      <price>14.50</price>
      <description>Makes you invisible</description>
    </item>
Name: 	Invisibility Cream, Levitation Salve, Blork and Freen Instameal, Grob winglets
Price: 	14.50, 23.99, 4.95, 3.56

Mathematica/Wolfram Language

example = Import["test.txt", "XML"];
Cases[example, XMLElement["item", _ , _] , Infinity] // First
Cases[example, XMLElement["price", _, List[n_]] -> n, Infinity] // Column
Cases[example, XMLElement["name", _, List[n_]] -> n, Infinity] // Column
Output:
XMLElement[item,{upc->123456789,stock->12},
{XMLElement[name,{},{Invisibility Cream}],XMLElement[price,{},{14.50}],XMLElement[description,{},{Makes you invisible}]}]
14.50
23.99
4.95
3.56
Invisibility Cream
Levitation Salve
Blork and Freen Instameal
Grob winglets

NetRexx

Translation of: Java
/* NetRexx */
options replace format comments java symbols binary

import javax.xml.parsers.
import javax.xml.xpath.
import org.w3c.dom.
import org.w3c.dom.Node
import org.xml.sax.

xmlStr = '' -
  || '<inventory title="OmniCorp Store #45x10^3">' -
  || '  <section name="health">' -
  || '    <item upc="123456789" stock="12">' -
  || '      <name>Invisibility Cream</name>' -
  || '      <price>14.50</price>' -
  || '      <description>Makes you invisible</description>' -
  || '    </item>' -
  || '    <item upc="445322344" stock="18">' -
  || '      <name>Levitation Salve</name>' -
  || '      <price>23.99</price>' -
  || '      <description>Levitate yourself for up to 3 hours per application</description>' -
  || '    </item>' -
  || '  </section>' -
  || '  <section name="food">' -
  || '    <item upc="485672034" stock="653">' -
  || '      <name>Blork and Freen Instameal</name>' -
  || '      <price>4.95</price>' -
  || '      <description>A tasty meal in a tablet; just add water</description>' -
  || '    </item>' -
  || '    <item upc="132957764" stock="44">' -
  || '      <name>Grob winglets</name>' -
  || '      <price>3.56</price>' -
  || '      <description>Tender winglets of Grob. Just add priwater</description>' -
  || '    </item>' -
  || '  </section>' -
  || '</inventory>'

expr1 = '/inventory/section/item[1]'
expr2 = '/inventory/section/item/price'
expr3 = '/inventory/section/item/name'
attr1 = 'upc'

do
  doc = DocumentBuilderFactory.newInstance().newDocumentBuilder().parse(InputSource(StringReader(xmlStr)))
  xpath = XPathFactory.newInstance().newXPath()

  -- Extract attribute from 1st item element
  say expr1
  say "  "(Node xpath.evaluate(expr1, doc, XPathConstants.NODE)).getAttributes().getNamedItem(attr1)
  say

  -- Extract and display all price elments
  nodes = NodeList xpath.evaluate(expr2, doc, XPathConstants.NODESET)
  say expr2
  loop i_ = 0 to nodes.getLength() - 1
    say Rexx(nodes.item(i_).getTextContent()).format(10, 2)
    end i_
  say

  -- Extract elements and store in an ArrayList
  nameList = java.util.List
  nameList = ArrayList()
  nodes = NodeList xpath.evaluate(expr3, doc, XPathConstants.NODESET)
  loop i_ = 0 to nodes.getLength() - 1
    nameList.add(nodes.item(i_).getTextContent())
    end i_

  -- display contents of ArrayList
  say expr3
  loop n_ = 0 to nameList.size() - 1
    say "  "nameList.get(n_)
    end n_
  say

catch ex = Exception
  ex.printStackTrace()
end

return

Output: 

/inventory/section/item[1]
  upc="123456789"

/inventory/section/item/price
        14.50
        23.99
         4.95
         3.56

/inventory/section/item/name
  Invisibility Cream
  Levitation Salve
  Blork and Freen Instameal
  Grob winglets

Nim

Library: libxml2

Nim standard library provides several modules to process XML, but none to process XPath requests. There is no third party library to do that either.

So we provide here a solution which uses the C "libxml2" library. Nim allows to interface with C with a great flexibility. Declaring the external functions is quite easy. The major part of the work consists to declare the data types. In "libxml2" there are a lot of structures and we have translated only what is needed to solve the task (or actually a bit more).

For the first request, we use //section[1]/item[1] instead of //item[1] (this is also what the Python version does). The latter request works but it returns the first element in each section which doesn’t seem to be what is expected. 

import sequtils, strutils

const LibXml = "libxml2.so"

type

  XmlDocPtr = pointer

  XmlXPathContextPtr = pointer

  XmlElementKind = enum
    xmlElementNode =      1
    xmlAttributeNode =    2
    xmlTextNode =         3
    xmlCdataSectionNode = 4
    xmlEntityRefNode =    5
    xmlEntityNode =       6
    xmlPiNode =           7
    xmlCommentNode =      8
    xmlDocumentNode =     9
    xmlDocumentTypeNode = 10
    xmlDocumentFragNode = 11
    xmlNotationNode =     12
    xmlHtmlDocumentNode = 13
    xmlDtdNode =          14
    xmlElementDecl =      15
    xmlAttributeDecl =    16
    xmlEntityDecl =       17
    xmlNamespaceDecl =    18
    xmlXincludeStart =    19
    xmlXincludeEnd =      20

  XmlNsKind = XmlElementKind

  XmlNsPtr = ptr XmlNs
  XmlNs = object
    next: XmlNsPtr
    kind: XmlNsKind
    href: cstring
    prefix: cstring
    private: pointer
    context: XmlDocPtr

  XmlAttrPtr = pointer

  XmlNodePtr = ptr XmlNode
  XmlNode = object
    private: pointer
    kind: XmlElementKind
    name: cstring
    children: XmlNodePtr
    last: XmlNodePtr
    parent: XmlNodePtr
    next: XmlNodePtr
    prev: XmlNodePtr
    doc: XmlDocPtr
    ns: XmlNsPtr
    content: cstring
    properties: XmlAttrPtr
    nsDef: XmlNsPtr
    psvi: pointer
    line: cushort
    extra: cushort

  XmlNodeSetPtr = ptr XmlNodeSet
  XmlNodeSet = object
    nodeNr: cint
    nodeMax: cint
    nodeTab: ptr UncheckedArray[XmlNodePtr]

  XmlPathObjectKind = enum
      xpathUndefined
      xpathNodeset
      xpathBoolean
      xpathNumber
      xpathString
      xpathPoint
      xpathRange
      xpathLocationset
      xpathUsers
      xpathXsltTree

  XmlXPathObjectPtr = ptr XmlXPathObject
  XmlXPathObject = object
    kind: XmlPathObjectKind
    nodeSetVal: XmlNodeSetPtr
    boolVal: cint
    floatVal: cdouble
    stringVal: cstring
    user: pointer
    index: cint
    user2: pointer
    index2: cint

  XmlSaveCtxtPtr = pointer

  XmlBufferPtr = pointer


# Declaration of needed "libxml2" procedures.
proc xmlParseFile(docName: cstring): XmlDocPtr
  {.cdecl, dynlib: LibXml, importc: "xmlParseFile".}

proc xmlXPathNewContext(doc: XmlDocPtr): XmlXPathContextPtr
  {.cdecl, dynlib: LibXml, importc: "xmlXPathNewContext".}

proc xmlXPathEvalExpression(str: cstring; ctxt: XmlXPathContextPtr): XmlXPathObjectPtr
  {.cdecl, dynlib: LibXml, importc: "xmlXPathEvalExpression".}

proc xmlXPathFreeContext(ctxt: XmlXPathContextPtr)
  {.cdecl, dynlib: LibXml, importc: "xmlXPathFreeContext".}

proc xmlXPathFreeObject(obj: XmlXPathObjectPtr)
  {.cdecl, dynlib: LibXml, importc: "xmlXPathFreeObject".}

proc xmlSaveToBuffer(vuffer: XmlBufferPtr; encoding: cstring; options: cint): XmlSaveCtxtPtr
  {.cdecl, dynlib: LibXml, importc: "xmlSaveToBuffer".}

proc xmlBufferCreate(): XmlBufferPtr
  {.cdecl, dynlib: LibXml, importc: "xmlBufferCreate".}

proc xmlBufferFree(buf: XmlBufferPtr)
  {.cdecl, dynlib: LibXml, importc: "xmlBufferCreate".}

proc xmlBufferContent(buf: XmlBufferPtr): cstring
  {.cdecl, dynlib: LibXml, importc: "xmlBufferContent".}

proc xmlSaveTree(ctxt: XmlSaveCtxtPtr; cur: XmlNodePtr): clong
  {.cdecl, dynlib: LibXml, importc: "xmlSaveTree".}

proc xmlSaveClose(ctxt: XmlSaveCtxtPtr)
  {.cdecl, dynlib: LibXml, importc: "xmlSaveClose".}


proc `$`(node: XmlNodePtr): string =
  ## Return the representation of a node.
  let buffer = xmlBufferCreate()
  let saveContext = xmlSaveToBuffer(buffer, nil, 0)
  discard saveContext.xmlSaveTree(node)
  saveContext.xmlSaveClose()
  result = $buffer.xmlBufferContent()
  xmlBufferFree(buffer)


iterator nodes(xpath: string; context: XmlXPathContextPtr): XmlNodePtr =
  ## Yield the nodes which fit the XPath request.
  let xpathObj = xmlXPathEvalExpression(xpath, context)
  if xpathObj.isNil:
    quit "Failed to evaluate XPath: " & xpath, QuitFailure
  assert xpathObj.kind == xpathNodeset
  let nodeSet = xpathObj.nodeSetVal
  if not nodeSet.isNil:
    for i in 0..<nodeSet.nodeNr:
      yield nodeSet.nodeTab[i]
  xmlXPathFreeObject(xpathObj)


# Load and parse XML file.
let doc = xmlParseFile("xpath_test.xml")
if doc.isNil:
  quit "Unable to load and parse document", QuitFailure

# Create an XPath context.
let context = xmlXPathNewContext(doc)
if context.isNil:
  quit "Failed to create XPath context", QuitFailure

var xpath = "//section[1]/item[1]"
echo "Request $#:".format(xpath)
for node in nodes(xpath, context):
  echo node
echo()

xpath = "//price/text()"
echo "Request $#:".format(xpath)
for node in nodes(xpath, context):
  echo node.content
echo()

xpath = "//name"
echo "Request $#:".format(xpath)
let names = toSeq(nodes(xpath, context)).mapIt(it.children.content)
echo names

xmlXPathFreeContext(context)
Output:
Request //section[1]/item[1]:
<item upc="123456789" stock="12">
      <name>Invisibility Cream</name>
      <price>14.50</price>
      <description>Makes you invisible</description>
    </item>

Request //price/text():
14.50
23.99
4.95
3.56

Request //name:
@["Invisibility Cream", "Levitation Salve", "Blork and Freen Instameal", "Grob winglets"]

Objeck

XPath is used to fetch element tags. 

use XML;

bundle Default {
  class Test {
    function : Main(args : String[]) ~ Nil {
      in := String->New();
      in->Append("<inventory title=\"OmniCorp Store #45x10^3\">");
      in->Append("<section name=\"health\">");
      in->Append("<item upc=\"123456789\" stock=\"12\">");
      in->Append("<name>Invisibility Cream</name>");
      in->Append("<price>14.50</price>");
      in->Append("<description>Makes you invisible</description>");
      in->Append("</item>");
      in->Append("<item upc=\"445322344\" stock=\"18\">");
      in->Append("<name>Levitation Salve</name>");
      in->Append("<price>23.99</price>");
      in->Append("<description>Levitate yourself for up to 3 hours per application</description>");
      in->Append("</item>");
      in->Append("</section>");
      in->Append("<section name=\"food\">");
      in->Append("<item upc=\"485672034\" stock=\"653\">");
      in->Append("<name>Blork and Freen Instameal</name>");
      in->Append("<price>4.95</price>");
      in->Append("<description>A tasty meal in a tablet; just add water</description>");
      in->Append("</item>");
      in->Append("<item upc=\"132957764\" stock=\"44\">");
      in->Append("<name>Grob winglets</name>");
      in->Append("<price>3.56</price>");
      in->Append("<description>Tender winglets of Grob. Just add water</description>");
      in->Append("</item>");
      in->Append("</section>");
      in->Append("</inventory>");
    
      parser := XmlParser->New(in);
      if(parser->Parse()) {
        # get first item
        results := parser->FindElements("//inventory/section[1]/item[1]");
        if(results <> Nil) {
          IO.Console->Instance()->Print("items: ")->PrintLine(results->Size());
        };
        # get all prices
        results := parser->FindElements("//inventory/section/item/price");
        if(results <> Nil) {
          each(i : results) {          
            element := results->Get(i)->As(XMLElement);
            element->GetContent()->PrintLine();
          };
        };
        # get names
        results := parser->FindElements("//inventory/section/item/name");
        if(results <> Nil) {
          IO.Console->Instance()->Print("names: ")->PrintLine(results->Size());
        };
      };
    }
  }
}

Oz

We implement a small subset of XPath for this task: 

declare
  [XMLParser] = {Module.link ['x-oz://system/xml/Parser.ozf']}

  proc {Main Data}
     Parser = {New XMLParser.parser init}
     [Doc] = {Parser parseVS(Data $)}

     FirstItem = {XPath Doc [inventory section item]}.1

     Prices = {XPath Doc [inventory section item price Text]}

     Names = {XPath Doc [inventory section item name]}
  in
     {ForAll Prices System.showInfo}
  end

  %%
  %% Emulation of some XPath functionality:
  %%

  fun {XPath Doc Path}
     P|Pr = Path
  in
     Doc.name = P %% assert
     {FoldL Pr XPathStep [Doc]}
  end

  fun {XPathStep Elements P}
     if {IsProcedure P} then
        {Map Elements P}
     else
        {FilteredChildren Elements P}
     end
  end

  %% A flat list of all Type-children of all Elements.
  fun {FilteredChildren Elements Type}
     {Flatten
      {Map Elements
       fun {$ E}
	  {Filter E.children
	   fun {$ X}
	      case X of element(name:!Type ...) then true
	      else false
	      end
	   end}
       end}}
  end

  %% PCDATA of an element as a ByteString
  fun {Text Element}
     Texts = for Child in Element.children collect:C do
		case Child of text(data:BS ...) then {C BS} end
	     end
  in
     {FoldR Texts ByteString.append {ByteString.make nil}}
  end
  
  Data =
   "<inventory title=\"OmniCorp Store #45x10^3\">"
  #"  <section name=\"health\">"
  #"    <item upc=\"123456789\" stock=\"12\">"
  #"      <name>Invisibility Cream</name>"
  #"      <price>14.50</price>"
  #"      <description>Makes you invisible</description>"
  #"    </item>"
  #"    <item upc=\"445322344\" stock=\"18\">"
  #"      <name>Levitation Salve</name>"
  #"      <price>23.99</price>"
  #"      <description>Levitate yourself for up to 3 hours per application</description>"
  #"    </item>"
  #"  </section>"
  #"  <section name=\"food\">"
  #"    <item upc=\"485672034\" stock=\"653\">"
  #"      <name>Blork and Freen Instameal</name>"
  #"      <price>4.95</price>"
  #"      <description>A tasty meal in a tablet; just add water</description>"
  #"    </item>"
  #"    <item upc=\"132957764\" stock=\"44\">"
  #"      <name>Grob winglets</name>"
  #"      <price>3.56</price>"
  #"      <description>Tender winglets of Grob. Just add water</description>"
  #"    </item>"
  #"  </section>"
  #"</inventory>"
in
  {Main Data}

Perl

Library: XML::XPathXPath
use XML::XPath qw();

my $x = XML::XPath->new('<inventory ... </inventory>');

[$x->findnodes('//item[1]')->get_nodelist]->[0];
print $x->findnodes_as_string('//price');
$x->findnodes('//name')->get_nodelist;

Phix

Phix has no direct support for XPath, but achieving the requirements using the standard xml_parse() is not exactly difficult. 

include builtins/xml.e
constant xml_txt = """
<inventory title="OmniCorp Store #45x10^3">
  <section name="health">
    <item upc="123456789" stock="12">
      <name>Invisibility Cream</name>
      <price>14.50</price>
      <description>Makes you invisible</description>
    </item>
    <item upc="445322344" stock="18">
      <name>Levitation Salve</name>
      <price>23.99</price>
      <description>Levitate yourself for up to 3 hours per application</description>
    </item>
  </section>
  <section name="food">
    <item upc="485672034" stock="653">
      <name>Blork and Freen Instameal</name>
      <price>4.95</price>
      <description>A tasty meal in a tablet; just add water</description>
    </item>
    <item upc="132957764" stock="44">
      <name>Grob winglets</name>
      <price>3.56</price>
      <description>Tender winglets of Grob. Just add water</description>
    </item>
  </section>
</inventory>
""",
-- or, of course, xml_txt = get_text("input.xml")
    xml = xml_parse(xml_txt)
 
sequence sections = xml_get_nodes(xml[XML_CONTENTS],"section"),
         item1 = {},
         prices = {},
         names = {}
 
for s=1 to length(sections) do
    sequence items = xml_get_nodes(sections[s],"item")
    if item1={} then item1 = items[1] end if
    for i=1 to length(items) do
        prices = append(prices,xml_get_nodes(items[i],"price")[1][XML_CONTENTS])
        names = append(names,xml_get_nodes(items[i],"name")[1][XML_CONTENTS])
    end for
end for
 
puts(1,"===item[1]===\n")
sequence tmp = xml_new_doc(item1)
puts(1,xml_sprint(tmp))
puts(1,"===prices===\n")
pp(prices)
puts(1,"===names===\n")
pp(names,{pp_Maxlen,90})
Output:
===item[1]===
<?xml version="1.0" encoding="utf-8" ?>
<item upc="123456789" stock="12">
  <name>Invisibility Cream</name>
  <price>14.50</price>
  <description>Makes you invisible</description>
</item>
===prices===
{`14.50`, `23.99`, `4.95`, `3.56`}
===names===
{`Invisibility Cream`, `Levitation Salve`, `Blork and Freen Instameal`, `Grob winglets`}

PHP

<?php
//PHP5 only example due to changes in XML extensions between version 4 and 5 (Tested on PHP5.2.0)
$doc = DOMDocument::loadXML('<inventory title="OmniCorp Store #45x10^3">...</inventory>');
//Load from file instead with $doc = DOMDocument::load('filename');
$xpath = new DOMXPath($doc);
/* 
    1st Task: Retrieve the first "item" element
*/
$nodelist = $xpath->query('//item');
$result = $nodelist->item(0);
/* 
    2nd task: Perform an action on each "price" element (print it out)
*/
$nodelist = $xpath->query('//price');
for($i = 0; $i < $nodelist->length; $i++)
{
  //print each price element in the DOMNodeList instance, $nodelist, as text/xml followed by a newline
  print $doc->saveXML($nodelist->item($i))."\n";
}
/* 
    3rd Task: Get an array of all the "name" elements
*/
$nodelist = $xpath->query('//name');
//our array to hold all the name elements, though in practice you'd probably not need to do this and simply use the DOMNodeList
$result = array(); 
//a different way of iterating through the DOMNodeList
foreach($nodelist as $node)
{
  $result[] = $node; 
}

PicoLisp

(load "@lib/xm.l")

(let Sections (body (in "file.xml" (xml)))
   (pretty (car (body (car Sections))))
   (prinl)
   (for S Sections
      (for L (body S)
         (prinl (car (body L 'price))) ) )
   (make
      (for S Sections
         (for L (body S)
            (link (car (body L 'name))) ) ) ) )

Output: 

(item
   ((upc . "123456789") (stock . "12"))
   (name NIL "Invisibility Cream")
   (price NIL "14.50")
   (description NIL "Makes you invisible") )
14.50
23.99
4.95
3.56
-> ("Invisibility Cream" "Levitation Salve" "Blork and Freen Instameal" "Grob winglets")

PowerShell

Cast the $document string as [xml] and you have access to .NET methods affecting XML. 

$document = [xml]@'
<inventory title="OmniCorp Store #45x10^3">
  <section name="health">
    <item upc="123456789" stock="12">
      <name>Invisibility Cream</name>
      <price>14.50</price>
      <description>Makes you invisible</description>
    </item>
    <item upc="445322344" stock="18">
      <name>Levitation Salve</name>
      <price>23.99</price>
      <description>Levitate yourself for up to 3 hours per application</description>
    </item>
  </section>
  <section name="food">
    <item upc="485672034" stock="653">
      <name>Blork and Freen Instameal</name>
      <price>4.95</price>
      <description>A tasty meal in a tablet; just add water</description>
    </item>
    <item upc="132957764" stock="44">
      <name>Grob winglets</name>
      <price>3.56</price>
      <description>Tender winglets of Grob. Just add water</description>
    </item>
  </section>
</inventory>
'@

$query = "/inventory/section/item"
$items = $document.SelectNodes($query)

The first item: 

$items[0]
Output:
upc         : 123456789
stock       : 12
name        : Invisibility Cream
price       : 14.50
description : Makes you invisible

Get some useful information: 

$namesAndPrices = $items | Select-Object -Property name, price
$namesAndPrices
Output:
name                      price
----                      -----
Invisibility Cream        14.50
Levitation Salve          23.99
Blork and Freen Instameal 4.95 
Grob winglets             3.56

Here are the prices: 

$items.price
Output:
14.50
23.99
4.95
3.56

Here are the names: 

$items.name
Output:
Invisibility Cream
Levitation Salve
Blork and Freen Instameal
Grob winglets

Python

# Python has basic xml parsing built in

from xml.dom import minidom

xmlfile = file("test3.xml") # load xml document from file 
xmldoc = minidom.parse(xmlfile).documentElement # parse from file stream or...
xmldoc = minidom.parseString("<inventory title="OmniCorp Store #45x10^3">...</inventory>").documentElement # alternatively, parse a string
	
#  1st Task: Retrieve the first "item" element
i = xmldoc.getElementsByTagName("item") # get a list of all "item" tags
firstItemElement = i[0] # get the first element

# 2nd task: Perform an action on each "price" element (print it out)
for j in xmldoc.getElementsByTagName("price"): # get a list of all "price" tags
	print j.childNodes[0].data # XML Element . TextNode . data of textnode

# 3rd Task: Get an array of all the "name" elements
namesArray = xmldoc.getElementsByTagName("name")

In Python 2.5+ you can use ElementTree's limited XPath support 

import xml.etree.ElementTree as ET

xml = open('inventory.xml').read()
doc = ET.fromstring(xml)

doc = ET.parse('inventory.xml')  # or load it directly

# Note, ElementTree's root is the top level element. So you need ".//" to really start searching from top

# Return first Item
item1 = doc.find("section/item")  # or ".//item"

# Print each price
for p in doc.findall("section/item/price"):  # or ".//price"
    print "{0:0.2f}".format(float(p.text))  # could raise exception on missing text or invalid float() conversion

# list of names
names = doc.findall("section/item/name")  # or ".//name"

Or, you can install the lxml package and get full XPath support 

from lxml import etree

xml = open('inventory.xml').read()
doc = etree.fromstring(xml)

doc = etree.parse('inventory.xml')  # or load it directly

# Return first item
item1 = doc.xpath("//section[1]/item[1]")

# Print each price
for p in doc.xpath("//price"):
    print "{0:0.2f}".format(float(p.text))  # could raise exception on missing text or invalid float() conversion

names = doc.xpath("//name")  # list of names

R

Library: XML (R)
library("XML")
doc <- xmlInternalTreeParse("test3.xml")

# Retrieve the first "item" element
getNodeSet(doc, "//item")[[1]]

# Perform an action on each "price" element
sapply(getNodeSet(doc, "//price"), xmlValue)

# Get an array of all the "name" elements
sapply(getNodeSet(doc, "//name"), xmlValue)

Racket

#lang at-exp racket

(define input @~a{
  <inventory title="OmniCorp Store #45x10^3">
    <section name="health">
      <item upc="123456789" stock="12">
        <name>Invisibility Cream</name>
        <price>14.50</price>
        <description>Makes you invisible</description>
      </item>
      <item upc="445322344" stock="18">
        <name>Levitation Salve</name>
        <price>23.99</price>
        <description>Levitate yourself for up to 3 hours per application</description>
      </item>
    </section>
    <section name="food">
      <item upc="485672034" stock="653">
        <name>Blork and Freen Instameal</name>
        <price>4.95</price>
        <description>A tasty meal in a tablet; just add water</description>
      </item>
      <item upc="132957764" stock="44">
        <name>Grob winglets</name>
        <price>3.56</price>
        <description>Tender winglets of Grob. Just add water</description>
      </item>
    </section>
  </inventory>})

(require xml xml/path)

(define data (xml->xexpr
              ((eliminate-whitespace '(inventory section item))
               (read-xml/element (open-input-string input)))))

;; Retrieve the first "item" element
(displayln (xexpr->string (se-path* '(item) data)))
;; => <name>Invisibility Cream</name>

;; Perform an action on each "price" element (print it out)
(printf "Prices: ~a\n" (string-join (se-path*/list '(item price) data) ", "))
;; => Prices: 14.50, 23.99, 4.95, 3.56

;; Get an array of all the "name" elements
(se-path*/list '(item name) data)
;; => '("Invisibility Cream" "Levitation Salve" "Blork and Freen Instameal" "Grob winglets")

Raku

(formerly Perl 6) 

use XML::XPath;

my $XML = XML::XPath.new(xml => q:to/END/);
<inventory title="OmniCorp Store #45x10^3">
  <section name="health">
    <item upc="123456789" stock="12">
      <name>Invisibility Cream</name>
      <price>14.50</price>
      <description>Makes you invisible</description>
    </item>
    <item upc="445322344" stock="18">
      <name>Levitation Salve</name>
      <price>23.99</price>
      <description>Levitate yourself for up to 3 hours per application</description>
    </item>
  </section>
  <section name="food">
    <item upc="485672034" stock="653">
      <name>Blork and Freen Instameal</name>
      <price>4.95</price>
      <description>A tasty meal in a tablet; just add water</description>
    </item>
    <item upc="132957764" stock="44">
      <name>Grob winglets</name>
      <price>3.56</price>
      <description>Tender winglets of Grob. Just add water</description>
    </item>
  </section>
</inventory>
END

put "First item:\n", $XML.find('//item[1]')[0];

put "\nPrice elements:";
.contents.put for $XML.find('//price').List;

put "\nName elements:\n", $XML.find('//name')».contents.join: ', ';
Output:
First item:
<item upc="123456789" stock="12"> <name>Invisibility Cream</name>  <price>14.50</price>  <description>Makes you invisible</description>  </item>

Price elements:
14.50
23.99
4.95
3.56

Name elements:
Invisibility Cream, Levitation Salve, Blork and Freen Instameal, Grob winglets

Rascal

import lang::xml::DOM;
import Prelude;

public void get_first_item(loc a){
	D = parseXMLDOM(readFile(a));
	top-down-break visit(D){
		case E:element(_,"item",_): return println(xmlPretty(E));
	};
}

public void print_prices(loc a){
	D = parseXMLDOM(readFile(a));
	for(/element(_,"price",[charData(/str p)]) := D)
		println(p);
}

public list[str] get_names(loc a){
	D = parseXMLDOM(readFile(a));
	L = [];
	for(/element(_,"name",[charData(/str n)]) := D)
		L += n;
	return L;
}

Example output: 

rascal>get_first_item(|file:///Users/.../Desktop/xmlpath.xml|)
<?xml version="1.0" encoding="UTF-8"?>
<item stock="12" upc="123456789">
  <name>Invisibility Cream</name>
  <price>14.50</price>
  <description>Makes you invisible</description>
</item>


ok

rascal>print_prices(|file:///Users/.../Desktop/xmlpath.xml|)
14.50
23.99
4.95
3.56
ok

rascal>get_names(|file:///Users/.../Desktop/xmlpath.xml|)
list[str]: ["Invisibility Cream","Levitation Salve","Blork and Freen Instameal","Grob winglets"]

REXX

hard coded parsing

/*REXX program to parse various queries on an XML document  (from a file).    */
iFID='XPATH.XML'                       /*name of the input  XML  file (doc).  */
$=                                     /*string will contain the file's text. */
     do j=1  while  lines(iFID)\==0    /*read the entire file into a string.  */
     $=$ linein(iFID)                  /*append the line to the  $  string.   */
     end   /*j*/
                                       /* [↓]  show 1st  ITEM  in the document*/
parse var $  '<item '  item  "</item>"
say center('first item:',length(space(item)),'─')     /*display a nice header.*/
say space(item)
                                       /* [↓]  show all PRICES in the document*/
prices=                                /*nullify the list and add/append to it*/
$$=$                                   /*start with a fresh copy of document. */
     do  until $$=''                   /* [↓]  keep parsing string until done.*/
     parse var $$  '<price>'   price   '</price>' $$
     prices=prices price               /*add/append the price to the list.    */
     end   /*until*/
say
say center('prices:',length(space(prices)),'─')       /*display a nice header.*/
say space(prices)
                                       /* [↓]  show all  NAMES in the document*/
names.=                                /*nullify the list and add/append to it*/
L=length(' names: ')                   /*maximum length of any one list name. */
$$=$                                   /*start with a fresh copy of document. */
     do #=1  until $$=''               /* [↓]  keep parsing string until done.*/
     parse var $$  '<name>'   names.#   '</name>'   $$
     L=max(L,length(names.#))          /*L:  is used to find the widest name. */
     end   /*#*/

names.0=#-1;                  say      /*adjust the number of names (DO loop).*/
say center('names:',L,'─')             /*display a nicely formatted header.   */
     do k=1  for names.0               /*display all the names in the list.   */
     say names.k                       /*display a name from the  NAMES  list.*/
     end   /*k*/
                                       /*stick a fork in it,  we're all done. */

output 

──────────────────────────────────────────────────────────first item:──────────────────────────────────────────────────────────
upc="123456789" stock="12"> <name>Invisibility Cream</name> <price>14.50</price> <description>Makes you invisible</description>

───────prices:───────
14.50 23.99 4.95 3.56

─────────names:──────────
Invisibility Cream
Levitation Salve
Blork and Freen Instameal
Grob winglets

generic parsing

/*REXX program to parse various queries on an XML document  (from a file).    */
iFID='XPATH.XML'                       /*name of the input  XML  file (doc).  */
$=                                     /*string will contain the file's text. */
     do j=1  while  lines(iFID)\==0    /*read the entire file into a string.  */
     $=$ linein(iFID)                  /*append the line to the  $  string.   */
     end   /*j*/
                                       /* [↓]  display 1st ITEM in document.  */
call parser 'item', 0                  /*go and parse the all the  ITEMs.     */
say center('first item:',@L.1,'─')     /*display a nicely formatted header.   */
say @.1;    say                        /*display the first  ITEM  found.      */

call parser 'price'                    /*go and parse all the   PRICEs.       */
say center('prices:',length(@@@),'─')  /*display a nicely formatted header.   */
say @@@;    say                        /*display a list of all the prices.    */

call parser 'name'
say center('names:',@L,'─')            /*display a nicely formatted header.   */
                        do k=1  for #  /*display all the names in the list.   */
                        say @.k        /*display a name from the  NAMES  list.*/
                        end   /*k*/
exit                                   /*stick a fork in it,  we're all done. */
/*────────────────────────────────────────────────────────────────────────────*/
parser:  parse arg yy,tail,,@. @@. @@@;   $$=$;  @L=9;  yb='<'yy;   ye='</'yy">"
tail=word(tail 1, 1)                                /*use a tail  ">"  or not?*/
      do #=1  until  $$=''                          /*parse complete XML doc. */
      if tail  then parse  var  $$  (yb) '>' @@.# (ye) $$         /*find meat.*/
               else parse  var  $$  (yb)     @@.# (ye) $$         /*  "    "  */
      @.#=space(@@.#);   @@@=space(@@@ @.#)         /*shrink;  @@@=list of YY.*/
      @L.#=length(@.#);  @L=max(@L,@L.#)            /*length; maximum length. */
      end   /*#*/
#=#-1                                               /*adjust # of thing found.*/
return

output   is the same as the 1st version.

Ruby

Library: REXML
#Example taken from the REXML tutorial (http://www.germane-software.com/software/rexml/docs/tutorial.html)
require "rexml/document"
include REXML
#create the REXML Document from the string (%q is Ruby's multiline string, everything between the two @-characters is the string)
doc = Document.new(
        %q@<inventory title="OmniCorp Store #45x10^3">
             ...
           </inventory>
          @
                          )
# The invisibility cream is the first <item>
invisibility = XPath.first( doc, "//item" ) 
# Prints out all of the prices
XPath.each( doc, "//price") { |element| puts element.text }
# Gets an array of all of the "name" elements in the document.
names = XPath.match( doc, "//name" )

Scala

The code is entered in to Scala's REPL, to better show the results. 

scala> val xml: scala.xml.Elem =
     | <inventory title="OmniCorp Store #45x10^3">
     |   <section name="health">
     |     <item upc="123456789" stock="12">
     |       <name>Invisibility Cream</name>
     |       <price>14.50</price>
     |       <description>Makes you invisible</description>
     |     </item>
     |     <item upc="445322344" stock="18">
     |       <name>Levitation Salve</name>
     |       <price>23.99</price>
     |       <description>Levitate yourself for up to 3 hours per application</description>
     |     </item>
     |   </section>
     |   <section name="food">
     |     <item upc="485672034" stock="653">
     |       <name>Blork and Freen Instameal</name>
     |       <price>4.95</price>
     |       <description>A tasty meal in a tablet; just add water</description>
     |     </item>
     |     <item upc="132957764" stock="44">
     |       <name>Grob winglets</name>
     |       <price>3.56</price>
     |       <description>Tender winglets of Grob. Just add water</description>
     |     </item>
     |   </section>
     | </inventory>

scala> val firstItem = xml \\ "item" take 1
firstItem: scala.xml.NodeSeq =
NodeSeq(<item upc="123456789" stock="12">
      <name>Invisibility Cream</name>
      <price>14.50</price>
      <description>Makes you invisible</description>
    </item>)

scala> xml \\ "price" map (_.text) foreach println
14.50
23.99
4.95
3.56

scala> val names = (xml \\ "name").toArray
names: Array[scala.xml.Node] = Array(<name>Invisibility Cream</name>, <name>Levitation Salve</name>, <name>Blork and Freen Instameal</name>, <name>Grob winglets</name>)

SenseTalk

Set XMLSource to {{
<inventory title="OmniCorp Store #45x10^3">
  <section name="health">
    <item upc="123456789" stock="12">
      <name>Invisibility Cream</name>
      <price>14.50</price>
      <description>Makes you invisible</description>
    </item>
    <item upc="445322344" stock="18">
      <name>Levitation Salve</name>
      <price>23.99</price>
      <description>Levitate yourself for up to 3 hours per application</description>
    </item>
  </section>
  <section name="food">
    <item upc="485672034" stock="653">
      <name>Blork and Freen Instameal</name>
      <price>4.95</price>
      <description>A tasty meal in a tablet; just add water</description>
    </item>
    <item upc="132957764" stock="44">
      <name>Grob winglets</name>
      <price>3.56</price>
      <description>Tender winglets of Grob. Just add water</description>
    </item>
  </section>
</inventory>
}}

put node "//item[1]" of XMLSource
put node "//price/text()" of XMLSource
put all nodes "//name" of XMLSource
Output:
<item upc="123456789" stock="12">
  <name>Invisibility Cream</name>
  <price>14.50</price>
  <description>Makes you invisible</description>
</item>
14.50
(<name>Invisibility Cream</name>,<name>Levitation Salve</name>,<name>Blork and Freen Instameal</name>,<name>Grob winglets</name>)

Sidef

Translation of: Perl
require('XML::XPath');

var x = %s'XML::XPath'.new(ARGF.slurp);

[x.findnodes('//item[1]')][0];
say [x.findnodes('//price')].map{x.getNodeText(_)};
[x.findnodes('//name')];
Output:
[14.5, 23.99, 4.95, 3.56]

Tcl

Library: tDOM
# assume $xml holds the XML data
package require tdom
set doc [dom parse $xml]
set root [$doc documentElement]

set allNames [$root selectNodes //name]
puts [llength $allNames] ;# ==> 4

set firstItem [lindex [$root selectNodes //item] 0]
puts [$firstItem @upc] ;# ==> 123456789

foreach node [$root selectNodes //price] {
    puts [$node text]
}

TUSCRIPT

$$ MODE TUSCRIPT,{}
MODE DATA
$$ XML=*
<inventory title="OmniCorp Store #45x10³">
  <section name="health">
    <item upc="123456789" stock="12">
      <name>Invisibility Cream</name>
      <price>14.50</price>
      <description>Makes you invisible</description>
    </item>
    <item upc="445322344" stock="18">
      <name>Levitation Salve</name>
      <price>23.99</price>
      <description>Levitate yourself for up to 3 hours per application</description>
    </item>
  </section>
  <section name="food">
    <item upc="485672034" stock="653">
      <name>Blork and Freen Instameal</name>
      <price>4.95</price>
      <description>A tasty meal in a tablet; just add water</description>
    </item>
    <item upc="132957764" stock="44">
      <name>Grob winglets</name>
      <price>3.56</price>
      <description>Tender winglets of Grob. Just add water</description>
    </item>
  </section>
</inventory>
$$ MODE TUSCRIPT

FILE = "test.xml"
ERROR/STOP CREATE (file,fdf-o,-std-)
FILE/ERASE/UTF8 $FILE = xml

BUILD S_TABLE beg=":<item*>:<name>:<price>:"
BUILD S_TABLE end=":</item>:</name>:</price>:"
BUILD S_TABLE modifiedbeg=":<name>:<price>:"
BUILD S_TABLE modifiedend=":</name>:</price>:"
firstitem=names="",countitem=0
ACCESS q: READ/STREAM/UTF8 $FILE s,a/beg+t+e/end
LOOP
READ/EXIT q
IF (a=="<name>")  names=APPEND(names,t)
IF (a=="<price>") PRINT t
IF (a.sw."<item") countitem=1
IF (countitem==1) THEN
firstitem=CONCAT(firstitem,a)
firstitem=CONCAT(firstitem,t)
firstitem=CONCAT(firstitem,e)
 IF (e=="</item>") THEN
 COUNTITEM=0
 MODIFY ACCESS q s_TABLE modifiedbeg,-,modifiedend
 ENDIF
ENDIF
ENDLOOP
ENDACCESS q
ERROR/STOP CLOSE (file)
firstitem=EXCHANGE (firstitem,":{2-00} ::")
firstitem=INDENT_TAGS (firstitem,-," ")
names=SPLIT(names)
TRACE *firstitem,names

Output: 

14.50
23.99
4.95
3.56
TRACE *    63    -*TUSTEP.EDT
firstitem    = *
           1 = <item upc="123456789" stock="12">
           2 =  <name>Invisibility Cream</name>
           3 =  <price>14.50</price>
           4 =  <description>Makes you invisible</description>
           5 = </item>
names        = *
           1 = Invisibility Cream
           2 = Levitation Salve
           3 = Blork and Freen Instameal
           4 = Grob winglets

VBScript

Set objXMLDoc = CreateObject("msxml2.domdocument")

objXMLDoc.load("In.xml")

Set item_nodes = objXMLDoc.selectNodes("//item")
i = 1
For Each item In item_nodes
	If i = 1 Then
		WScript.StdOut.Write item.xml
		WScript.StdOut.WriteBlankLines(2)
		Exit For
	End If
Next

Set price_nodes = objXMLDoc.selectNodes("//price")
list_price = ""
For Each price In price_nodes
	list_price = list_price & price.text & ", "
Next
WScript.StdOut.Write list_price
WScript.StdOut.WriteBlankLines(2)

Set name_nodes = objXMLDoc.selectNodes("//name")
list_name = ""
For Each name In name_nodes
	list_name = list_name & name.text & ", "
Next
WScript.StdOut.Write list_name
WScript.StdOut.WriteBlankLines(2)
Output:
<item upc="123456789" stock="12">
	<name>Invisibility Cream</name>
	<price>14.50</price>
	<description>Makes you invisible</description>
</item>

14.50, 23.99, 4.95, 3.56, 

Invisibility Cream, Levitation Salve, Blork and Freen Instameal, Grob winglets,

Visual Basic .NET

Dim first_item = xml.XPathSelectElement("//item")
Console.WriteLine(first_item)
 
For Each price In xml.XPathSelectElements("//price")
    Console.WriteLine(price.Value)
Next
 
Dim names = (From item In xml.XPathSelectElements("//name") Select item.Value).ToArray

Wren

Library: Wren-pattern

Wren does not have built-in support for XML/XPath and, to my knowledge, there is no third party module which adds such support either. We therefore have to fall back on string pattern matching to perform the required queries. 

import "./pattern" for Pattern

var doc = """
<inventory title="OmniCorp Store #45x10^3">
  <section name="health">
    <item upc="123456789" stock="12">
      <name>Invisibility Cream</name>
      <price>14.50</price>
      <description>Makes you invisible</description>
    </item>
    <item upc="445322344" stock="18">
      <name>Levitation Salve</name>
      <price>23.99</price>
      <description>Levitate yourself for up to 3 hours per application</description>
    </item>
  </section>
  <section name="food">
    <item upc="485672034" stock="653">
      <name>Blork and Freen Instameal</name>
      <price>4.95</price>
      <description>A tasty meal in a tablet; just add water</description>
    </item>
    <item upc="132957764" stock="44">
      <name>Grob winglets</name>
      <price>3.56</price>
      <description>Tender winglets of Grob. Just add water</description>
    </item>
  </section>
</inventory>
"""

var p1 = Pattern.new("<item ")
var match1 = p1.find(doc)
var p2 = Pattern.new("<//item>")
var match2 = p2.find(doc)
System.print("The first 'item' element is:")
System.print("    " + doc[match1.index..match2.index + 6])

var p3 = Pattern.new("<price>[+1^<]<//price>")
var matches = p3.findAll(doc)
System.print("\nThe 'prices' are:")
for (m in matches) System.print(m.captures[0].text)

var p4 = Pattern.new("<name>[+1^<]<//name>")
var matches2 = p4.findAll(doc)
var names = matches2.map { |m| m.captures[0].text }.toList
System.print("\nThe 'names' are:")
System.print(names.join("\n"))
Output:
The first 'item' element is:
    <item upc="123456789" stock="12">
      <name>Invisibility Cream</name>
      <price>14.50</price>
      <description>Makes you invisible</description>
    </item>

The 'prices' are:
14.50
23.99
4.95
3.56

The 'names' are:
Invisibility Cream
Levitation Salve
Blork and Freen Instameal
Grob winglets


Library: Wren-xsequence

Since the first version was written, the above XML parser has appeared. Consequently, the solution can now be rewritten as follows, the output being the same as before.

Note that this library doesn't support XPath as such though for this particular task simple 'for' statements suffice. 

import "./xsequence" for XDocument

var xml = """
<inventory title="OmniCorp Store #45x10^3">
  <section name="health">
    <item upc="123456789" stock="12">
      <name>Invisibility Cream</name>
      <price>14.50</price>
      <description>Makes you invisible</description>
    </item>
    <item upc="445322344" stock="18">
      <name>Levitation Salve</name>
      <price>23.99</price>
      <description>Levitate yourself for up to 3 hours per application</description>
    </item>
  </section>
  <section name="food">
    <item upc="485672034" stock="653">
      <name>Blork and Freen Instameal</name>
      <price>4.95</price>
      <description>A tasty meal in a tablet; just add water</description>
    </item>
    <item upc="132957764" stock="44">
      <name>Grob winglets</name>
      <price>3.56</price>
      <description>Tender winglets of Grob. Just add water</description>
    </item>
  </section>
</inventory>
"""

var doc = XDocument.parse(xml)
System.print("The first 'item' element is:")
System.print(doc.root.element("section").element("item"))

var prices = []
var names = []
for (el in doc.root.elements) {
    for (el2 in el.elements) {
        prices.add(el2.element("price").value)
        names.add(el2.element("name").value)
    }
}
System.print("\nThe 'prices' are:\n%(prices.join("\n"))")
System.print("\nThe 'names' are:\n%(names.join("\n"))")

XPL0

To run: xml <xml.xml 

include xpllib; \for StrFind

char XML(1000000), P, P1, P2, Addr;
int  I, Ch;
[I:= 0;
loop    [Ch:= ChIn(1);
        XML(I):= Ch;
        if Ch = $1A \EOF\ then quit;
        I:= I+1;
        ];
XML(I):= 0;

P1:= StrFind(XML, "<item ");
P2:= StrFind(XML, "</item>");
Text(0, "The first 'item' element is:^m^j");
for P:= P1 to P2+6 do ChOut(0, P(0));
CrLf(0);

Text(0, "^m^jThe 'prices' are:^m^j");
Addr:= XML;
loop    [P1:= StrFind(Addr, "<price>");
        if P1 = 0 then quit;
        P2:= StrFind(Addr, "</price>");
        if P2 = 0 then quit;
        for P:= P1+7 to P2-1 do ChOut(0, P(0));
        CrLf(0);
        Addr:= P2+1;
        ];
Text(0, "^m^jThe 'names' are:^m^j");
Addr:= XML;
loop    [P1:= StrFind(Addr, "<name>");
        if P1 = 0 then quit;
        P2:= StrFind(Addr, "</name>");
        if P2 = 0 then quit;
        for P:= P1+6 to P2-1 do ChOut(0, P(0));
        CrLf(0);
        Addr:= P2+1;
        ];
]
Output:
The first 'item' element is:
<item upc="123456789" stock="12">
      <name>Invisibility Cream</name>
      <price>14.50</price>
      <description>Makes you invisible</description>
    </item>

The 'prices' are:
14.50
23.99
4.95
3.56

The 'names' are:
Invisibility Cream
Levitation Salve
Blork and Freen Instameal
Grob winglets

XProc

<p:pipeline xmlns:p="http://www.w3.org/ns/xproc"
  name="one-two-three"
  version="1.0">
  <p:identity>
    <p:input port="source">
      <p:inline>
        <root>
          <first/>
          <prices/>
          <names/>
        </root>
      </p:inline>
    </p:input>
  </p:identity>
  <p:insert match="/root/first" position="first-child">
    <p:input port="insertion" select="(//item)[1]">
      <p:pipe port="source" step="one-two-three"/>
    </p:input>
  </p:insert>
  <p:insert match="/root/prices" position="first-child">
    <p:input port="insertion" select="//price">
      <p:pipe port="source" step="one-two-three"/>
    </p:input>
  </p:insert>
  <p:insert match="/root/names" position="first-child">
    <p:input port="insertion" select="//name">
      <p:pipe port="source" step="one-two-three"/>
    </p:input>
  </p:insert>  
</p:pipeline>

XQuery

(: 
  1. Retrieve the first "item" element  
  Notice the braces around //item. This evaluates first all item elements and then retrieving the first one.
  Whithout the braces you get the first item for every section.
:)
let $firstItem := (//item)[1]

(: 2. Perform an action on each "price" element (print it out) :)
let $price := //price/data(.)

(: 3. Get an array of all the "name" elements  :) 
let $names := //name

return
  <result>
    <firstItem>{$firstItem}</firstItem>
    <prices>{$price}</prices>
    <names>{$names}</names>
  </result>

Performing this XQuery on the given input document results in 

<?xml version="1.0" encoding="UTF-8"?>
<result>
   <firstItem>
      <item upc="123456789" stock="12">
         <name>Invisibility Cream</name>
         <price>14.50</price>
         <description>Makes you invisible</description>
      </item>
   </firstItem>
   <prices>14.50 23.99 4.95 3.56</prices>
   <names>
      <name>Invisibility Cream</name>
      <name>Levitation Salve</name>
      <name>Blork and Freen Instameal</name>
      <name>Grob winglets</name>
   </names>
</result>

XSLT

<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
  <xsl:output method="text" />
  <xsl:template match="/">
  
    <!-- 1. first item element -->
    <xsl:text>
The first item element is</xsl:text>
    <xsl:value-of select="//item[1]" />
    
    <!-- 2. Print each price element -->
    <xsl:text>
The prices are: </xsl:text>
    <xsl:for-each select="//price">
      <xsl:text>
      </xsl:text>
      <xsl:copy-of select="." />
    </xsl:for-each>
    
    <!-- 3. Collect all the name elements -->
    <xsl:text>
The names are: </xsl:text>
    <xsl:copy-of select="//name" />
  </xsl:template>  
</xsl:stylesheet>
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