Reflection/List properties: Difference between revisions

Add Ecstasy example
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=={{header|C sharp}}==
{{works with|C sharp|7}}
<langsyntaxhighlight lang="csharp">using System;
using System.Collections.Generic;
using System.Linq;
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}
 
}</langsyntaxhighlight>
{{out}}
<pre>
Line 53:
(<PublicNumber>k__BackingField, 4)
(<PrivateNumber>k__BackingField, 2)
</pre>
 
=={{header|D}}==
<syntaxhighlight lang="d">import std.stdio;
 
struct S {
bool b;
 
void foo() {}
private void bar() {}
}
 
class C {
bool b;
 
void foo() {}
private void bar() {}
}
 
void printProperties(T)() if (is(T == class) || is(T == struct)) {
import std.stdio;
import std.traits;
 
writeln("Properties of ", T.stringof, ':');
foreach (m; __traits(allMembers, T)) {
static if (__traits(compiles, (typeof(__traits(getMember, T, m))))) {
alias typeof(__traits(getMember, T, m)) ti;
static if (!isFunction!ti) {
writeln(" ", m);
}
}
}
}
 
void main() {
printProperties!S;
printProperties!C;
}</syntaxhighlight>
{{out}}
<pre>Properties of S:
b
Properties of C:
b</pre>
 
=={{header|Ecstasy}}==
For any object, the type of that object provides access to its properties:
 
<syntaxhighlight lang="ecstasy">
module test {
void run() {
@Inject Console console;
Property[] properties = &this.actualType.properties;
console.print($"The properties of {this}: {properties}");
}
}
</syntaxhighlight>
 
{{out}}
<pre>
x$ xec test
The properties of test: [immutable Array<Class<Object, Object, Object, Struct>> classes, immutable Map<String, Class<Object, Object, Object, Struct>> classByName, String simpleName, String qualifiedName, Version version, immutable Map<String, Module> modulesByPath]
</pre>
 
=={{header|Elena}}==
ELENA 6.x :
Using a special property type - dto_prop.
<syntaxhighlight lang="elena">import system'routines;
ELENA 3.4 :
<lang elena>import system'routines.dynamic;
import extensions.;
class MyClass
{
int dto_prop X : : x.prop;
literal dto_propstring Y :: y.prop;
}
 
public program()
{
[
var o := new MyClass::
{
@xthis X := 2.;
@ythis Y := "String".;
}.;
 
MyClass __properties; forEach.__getProperties().forEach::(p)
[{
console .printLine("o.",p,"=",o~p get).getPropertyValue(o))
].}
}</syntaxhighlight>
]</lang>
{{out}}
<pre>
Line 89 ⟶ 150:
=={{header|Factor}}==
Mirrors present an object's slots and slot values as an associative structure.
<langsyntaxhighlight lang="factor">USING: assocs kernel math mirrors prettyprint strings ;
 
TUPLE: foo
Line 98 ⟶ 159:
 
"apple" "banana" 200 <foo> <mirror>
[ >alist ] [ object-slots ] bi [ . ] bi@</langsyntaxhighlight>
{{out}}
<pre>
Line 133 ⟶ 194:
 
=={{header|Go}}==
<langsyntaxhighlight Golang="go">package main
 
import (
Line 166 ⟶ 227:
}
fmt.Println()
}</langsyntaxhighlight>
{{out}}
<pre>
Line 179 ⟶ 240:
Y int true
</pre>
 
=={{header|Groovy}}==
{{trans|Java}}
<syntaxhighlight lang="groovy">import java.lang.reflect.Field
 
@SuppressWarnings("unused")
class ListProperties {
public int examplePublicField = 42
private boolean examplePrivateField = true
 
static void main(String[] args) {
ListProperties obj = new ListProperties()
Class clazz = obj.class
 
println "All public fields (including inherited):"
(clazz.fields).each { Field f ->
printf "%s\t%s\n", f, f.get(obj)
}
println()
 
println "All declared fields (excluding inherited):"
clazz.getDeclaredFields().each { Field f ->
f.accessible = true
printf "%s\t%s\n", f, f.get(obj)
}
}
}</syntaxhighlight>
{{out}}
<pre>All public fields (including inherited):
public int ListProperties.examplePublicField 42
public static transient boolean ListProperties.__$stMC false
 
All declared fields (excluding inherited):
public int ListProperties.examplePublicField 42
private boolean ListProperties.examplePrivateField true
private static org.codehaus.groovy.reflection.ClassInfo ListProperties.$staticClassInfo org.codehaus.groovy.reflection.ClassInfo@400cff1a
public static transient boolean ListProperties.__$stMC false
private transient groovy.lang.MetaClass ListProperties.metaClass groovy.lang.MetaClassImpl@275710fc[class ListProperties]
private static org.codehaus.groovy.reflection.ClassInfo ListProperties.$staticClassInfo$ null
private static java.lang.ref.SoftReference ListProperties.$callSiteArray java.lang.ref.SoftReference@525f1e4e</pre>
 
=={{header|J}}==
Line 185 ⟶ 286:
 
=={{header|Java}}==
<langsyntaxhighlight lang="java">import java.lang.reflect.Field;
 
public class ListFields {
Line 205 ⟶ 306:
}
}
}</langsyntaxhighlight>
{{out}}
<pre>
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There are multiple ways of getting property names, each of which include different subsets of an object's properties, such as enumerable or inherited properties. Properties in JavaScript can be enumerable or non-enumerable; enumerable properties are accessable when looping over the object with <code>for</code>. <code>Object.getOwnPropertyNames()</code>.
 
<langsyntaxhighlight lang="javascript">var obj = Object.create({
name: 'proto',
proto: true,
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Object.entries(obj);
//[["name", "obj"], ["obj", true], ["doStuff", function()]]
</syntaxhighlight>
</lang>
 
=={{header|jq}}==
{{works with|jq}}
 
Various properties of JSON values are directly accessible via the
built-in functions `type`, `length` (except for booleans), and, for
JSON objects, `keys` and `keys_unsorted`:
 
* `type` returns the JSON type;
* `length` returns an array's length, the number of (distinct) keys of an object, the absolute value of a number, and 0 for `null`;
 
Note that gojq (the Go implementation of jq) does not support `keys_unsorted`.
 
Other properties can be ascertained programmatically.
See e.g. '''schema.jq''' (https://gist.github.com/pkoppstein/a5abb4ebef3b0f72a6ed) for a schema-inference engine for JSON written in jq; the inferred schemas are themselves JSON documents.
 
'''Example'''
<syntaxhighlight lang="jq">
# Use jq's built-ins to generate a (recursive) synopsis of .
def synopsis:
if type == "boolean" then "Type: \(type)"
elif type == "object"
then "Type: \(type) length:\(length)",
(keys_unsorted[] as $k
| "\($k): \(.[$k] | synopsis )")
else "Type: \(type) length: \(length)"
end;
 
true, null, [1,2], {"a": {"b": 3, "c": 4}, "x": "Rosetta Code"}, now
| ("\n\(.) ::", synopsis)
</syntaxhighlight>
{{out}}
<pre>
true ::
Type: boolean
 
null ::
Type: null length: 0
 
[1,2] ::
Type: array length: 2
 
{"a":{"b":3,"c":4},"x":[0,1]} ::
Type: object length:2
a: Type: object length:2
a: b: Type: number length: 3
a: c: Type: number length: 4
x: Type: string length: 12
 
1629526284.540229 ::
Type: number length: 1629526284.540229
</pre>
 
 
=={{header|Julia}}==
{{works with|Julia|0.6}}
 
<langsyntaxhighlight lang="julia">for obj in (Int, 1, 1:10, collect(1:10), now())
println("\nObject: $obj\nDescription:")
dump(obj)
end</langsyntaxhighlight>
 
{{out}}
Line 288 ⟶ 442:
 
=={{header|Kotlin}}==
<langsyntaxhighlight lang="scala">// version 1.1
 
import kotlin.reflect.full.memberProperties
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println("${prop.name.padEnd(13)} -> ${prop.get(example)}")
}
}</langsyntaxhighlight>
 
{{out}}
Line 327 ⟶ 481:
 
=={{header|Lingo}}==
<langsyntaxhighlight lang="lingo">obj = script("MyClass").new()
obj.foo = 23
obj.bar = 42
Line 337 ⟶ 491:
repeat with i = 1 to cnt
put obj.getPropAt(i)&" = "&obj[i]
end repeat</langsyntaxhighlight>
 
{{Out}}
Line 344 ⟶ 498:
-- "foo = 23"
</pre>
 
=={{header|Lua}}==
<syntaxhighlight lang="lua">a = 1
b = 2.0
c = "hello world"
 
function listProperties(t)
if type(t) == "table" then
for k,v in pairs(t) do
if type(v) ~= "function" then
print(string.format("%7s: %s", type(v), k))
end
end
end
end
 
print("Global properties")
listProperties(_G)
print("Package properties")
listProperties(package)</syntaxhighlight>
{{out}}
<pre>Global properties
number: a
table: string
number: b
table: package
table: os
table: io
table: arg
string: c
table: math
table: debug
table: table
table: coroutine
table: _G
string: _VERSION
Package properties
table: preload
table: loaded
table: loaders
string: cpath
string: config
string: path</pre>
 
=={{header|Nanoquery}}==
<syntaxhighlight lang="nanoquery">// declare a class that has fields to be listed
class Fields
declare static field1 = "this is a static field. it will not be listed"
declare field2
declare field3
declare field4
end
 
// list all the fields in the class
for fieldname in Fields.getFieldNames()
println fieldname
end</syntaxhighlight>
 
{{out}}
<pre>field3
field2
field4</pre>
=={{header|Nim}}==
<syntaxhighlight lang="nim">type
Foo = object
a: float
b: string
c: seq[int]
let f = Foo(a: 0.9, b: "hi", c: @[1,2,3])
for n, v in f.fieldPairs:
echo n, ": ", v</syntaxhighlight>
{{out}}
<pre>a: 0.9
b: hi
c: @[1, 2, 3]</pre>
 
=={{header|Objective-C}}==
<langsyntaxhighlight lang="objc">#import <Foundation/Foundation.h>
#import <objc/runtime.h>
 
Line 401 ⟶ 630:
 
return 0;
}</langsyntaxhighlight>
{{out}}
<pre>
Line 419 ⟶ 648:
 
Many of these options are also supported by other REXX implementations.
<langsyntaxhighlight lang="oorexx">/* REXX demonstrate uses of datatype() */
/* test values */
d.1=''
Line 463 ⟶ 692:
Say ol
End
Say hdr</langsyntaxhighlight>
{{out}}
<pre> A B I L M N O S U V W X 9 datatype(v)
Line 483 ⟶ 712:
=={{header|Perl}}==
In Perl's bare-bones native OO system, an object is sometimes nothing more than a hash blessed into a class. It's properties could be simply listed by iterating over the keys. However more complex data structures can be present, so the safest option is always to use <code>Data::Dumper</code> to examine an object.
<langsyntaxhighlight lang="perl">{
package Point;
use Class::Spiffy -base;
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say Dumper $p1;
say Dumper $c1;
say Dumper $c2;</langsyntaxhighlight>
{{out}}
<pre>$VAR1 = bless( {
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}, 'Circle' );
</pre>
=={{header|Perl 6}}==
 
=={{header|Phix}}==
You can get a list of an object's attributes (instance variables) using <tt>.^attributes</tt>, which is part of the [https://docs.perl6.org/type/Metamodel$COLON$COLONClassHOW Meta Object Protocol]..<br>
{{libheader|Phix/Class}}
Each is represented as an <tt>Attribute</tt> object that contains a bunch of info:
Needs 0.8.1+
Note that content from and parameters to get_struct_type/fields() may change between releases.<br>
You should certainly be prepared for them to return NULL for unrecognised field names and types.<br>
Technically the code below is re-fetching tid and flags before returning them in a textual format.
 
<!--<syntaxhighlight lang="phix">-->
<lang perl6>class Foo {
<span style="color: #008080;">class</span> <span style="color: #000000;">c</span> <span style="color: #7060A8;">nullable</span>
has $!a = now;
<span style="color: #004080;">integer</span> <span style="color: #004080;">int</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">1</span>
has Str $.b;
<span style="color: #008080;">public</span> <span style="color: #004080;">atom</span> <span style="color: #000000;">atm</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">2.3</span>
has Int $.c is rw;
<span style="color: #004080;">string</span> <span style="color: #000000;">str</span> <span style="color: #0000FF;">=</span> <span style="color: #008000;">"4point5"</span>
}
<span style="color: #004080;">sequence</span> <span style="color: #000000;">seq</span>
 
<span style="color: #008080;">public</span><span style="color: #0000FF;">:</span>
my $object = Foo.new: b => "Hello", c => 42;
<span style="color: #004080;">object</span> <span style="color: #000000;">obj</span> <span style="color: #0000FF;">=</span> <span style="color: #0000FF;">{</span><span style="color: #008000;">"an object"</span><span style="color: #0000FF;">}</span>
 
<span style="color: #000000;">c</span> <span style="color: #000000;">child</span>
for $object.^attributes {
<span style="color: #008080;">private</span> <span style="color: #008080;">function</span> <span style="color: #000000;">foo</span><span style="color: #0000FF;">();</span>
say join ", ", .name, .readonly, .container.^name, .get_value($object);
<span style="color: #008080;">public</span> <span style="color: #008080;">procedure</span> <span style="color: #000000;">bar</span><span style="color: #0000FF;">();</span>
}</lang>
<span style="color: #008080;">end</span> <span style="color: #008080;">class</span>
<span style="color: #000000;">c</span> <span style="color: #000000;">c_instance</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">new</span><span style="color: #0000FF;">()</span>
<span style="color: #008080;">include</span> <span style="color: #000000;">builtins</span><span style="color: #0000FF;">\</span><span style="color: #000000;">structs</span><span style="color: #0000FF;">.</span><span style="color: #000000;">e</span> <span style="color: #7060A8;">as</span> <span style="color: #000000;">structs</span>
<span style="color: #008080;">function</span> <span style="color: #000000;">nulls</span><span style="color: #0000FF;">(</span><span style="color: #004080;">object</span> <span style="color: #000000;">s</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">return</span> <span style="color: #008080;">iff</span><span style="color: #0000FF;">(</span><span style="color: #000000;">s</span><span style="color: #0000FF;">=</span><span style="color: #004600;">NULL</span><span style="color: #0000FF;">?</span><span style="color: #008000;">"NULL"</span><span style="color: #0000FF;">:</span><span style="color: #000000;">s</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">end</span> <span style="color: #008080;">function</span>
<span style="color: #004080;">sequence</span> <span style="color: #000000;">fields</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">structs</span><span style="color: #0000FF;">:</span><span style="color: #000000;">get_struct_fields</span><span style="color: #0000FF;">(</span><span style="color: #000000;">c</span><span style="color: #0000FF;">)</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;">fields</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">do</span>
<span style="color: #0000FF;">{</span><span style="color: #004080;">string</span> <span style="color: #000000;">name</span><span style="color: #0000FF;">,</span> <span style="color: #004080;">integer</span> <span style="color: #000000;">tid</span><span style="color: #0000FF;">,</span> <span style="color: #004080;">integer</span> <span style="color: #000000;">flags</span><span style="color: #0000FF;">}</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">fields</span><span style="color: #0000FF;">[</span><span style="color: #000000;">i</span><span style="color: #0000FF;">]</span>
<span style="color: #008080;">if</span> <span style="color: #008080;">not</span> <span style="color: #7060A8;">and_bits</span><span style="color: #0000FF;">(</span><span style="color: #000000;">flags</span><span style="color: #0000FF;">,</span><span style="color: #000000;">SF_RTN</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">then</span> <span style="color: #000080;font-style:italic;">-- (exclude foo/bar)</span>
<span style="color: #004080;">string</span> <span style="color: #000000;">t</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">nulls</span><span style="color: #0000FF;">(</span><span style="color: #000000;">structs</span><span style="color: #0000FF;">:</span><span style="color: #000000;">get_field_type</span><span style="color: #0000FF;">(</span><span style="color: #000000;">c</span><span style="color: #0000FF;">,</span><span style="color: #000000;">name</span><span style="color: #0000FF;">,</span><span style="color: #004600;">true</span><span style="color: #0000FF;">)),</span>
<span style="color: #000000;">f</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">nulls</span><span style="color: #0000FF;">(</span><span style="color: #000000;">structs</span><span style="color: #0000FF;">:</span><span style="color: #000000;">get_field_flags</span><span style="color: #0000FF;">(</span><span style="color: #000000;">c</span><span style="color: #0000FF;">,</span><span style="color: #000000;">name</span><span style="color: #0000FF;">,</span><span style="color: #004600;">true</span><span style="color: #0000FF;">))</span>
<span style="color: #004080;">object</span> <span style="color: #000000;">v</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">nulls</span><span style="color: #0000FF;">(</span><span style="color: #000000;">structs</span><span style="color: #0000FF;">:</span><span style="color: #000000;">fetch_field</span><span style="color: #0000FF;">(</span><span style="color: #000000;">c_instance</span><span style="color: #0000FF;">,</span><span style="color: #000000;">name</span><span style="color: #0000FF;">,</span><span style="color: #000000;">c</span><span style="color: #0000FF;">))</span>
<span style="color: #7060A8;">printf</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"type:%-11s, name:%-5s, flags:%s, value:%v\n"</span><span style="color: #0000FF;">,{</span><span style="color: #000000;">t</span><span style="color: #0000FF;">,</span><span style="color: #000000;">name</span><span style="color: #0000FF;">,</span><span style="color: #000000;">f</span><span style="color: #0000FF;">,</span><span style="color: #000000;">v</span><span style="color: #0000FF;">})</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">for</span>
<!--</syntaxhighlight>-->
 
{{out}}
<pre>
type:ST_INTEGER , name:int , flags:SF_PRIVATE, value:1
$!a, True, Any, Instant:1470517602.295992
type:ST_ATOM , name:atm , flags:SF_PUBLIC, value:2.3
$!b, True, Str, Hello
type:ST_STRING , name:str , flags:SF_PRIVATE, value:"4point5"
$!c, False, Int, 42
type:ST_SEQUENCE, name:seq , flags:SF_PRIVATE, value:{}
type:ST_OBJECT , name:obj , flags:SF_PUBLIC, value:{"an object"}
type:c , name:child, flags:SF_PUBLIC, value:"NULL"
</pre>
 
Public attributes (in this case, <tt>$.b</tt> and <tt>$.c</tt>) are really just attributes for which the compiler also auto-generates a method of the same name. See [[Reflection/List_methods#Perl_6]].
 
=={{header|PHP}}==
<langsyntaxhighlight lang="php"><?
class Foo {
}
Line 556 ⟶ 806:
 
var_dump(get_object_vars($obj));
?></langsyntaxhighlight>
{{out}}
<pre>
Line 566 ⟶ 816:
}
</pre>
 
=={{header|PicoLisp}}==
The function <code>show</code> can be used to print all properties of an object.
 
First we define a rectangle class <code>+Rectangle</code> as subclass of a shape class <code>+Shape</code>:
 
<syntaxhighlight lang="picolisp">
# The Rectangle class
(class +Rectangle +Shape)
# dx dy
 
(dm T (X Y DX DY)
(super X Y)
(=: dx DX)
(=: dy DY) )
 
(dm area> ()
(* (: dx) (: dy)) )
 
(dm perimeter> ()
(* 2 (+ (: dx) (: dy))) )
 
(dm draw> ()
(drawRect (: x) (: y) (: dx) (: dy)) ) # Hypothetical function 'drawRect'
</syntaxhighlight>
 
Then we can create an object of the +Rectangle class and check its properties using the <code>show</code> function.
 
<syntaxhighlight lang="text">
: (setq R (new '(+Rectangle) 0 0 30 20))
-> $177356065126400
 
: (show R)
$177715702441044 (+Rectangle)
dy 20
dx 30
y 0
x 0
-> $177715702441044
</syntaxhighlight>
 
 
=={{header|PL/I}}==
Line 574 ⟶ 865:
 
Here we find the properties of a <code>[DateTime]</code> object:
<syntaxhighlight lang="powershell">
<lang PowerShell>
Get-Date | Get-Member -MemberType Property
</syntaxhighlight>
</lang>
 
{{Out}}
Line 599 ⟶ 890:
</pre>
The "Add" methods of a <code>[DateTime]</code> object:
<syntaxhighlight lang="powershell">
<lang PowerShell>
Get-Date | Get-Member -MemberType Method -Name Add*
</syntaxhighlight>
</lang>
{{Out}}
<pre>
Line 622 ⟶ 913:
The <code>[https://docs.python.org/3.5/library/functions.html#dir dir()]</code> function and Python's <code>[https://docs.python.org/3.5/library/inspect.html#module-inspect inspect]</code> module both will list properties.
 
<langsyntaxhighlight lang="python">class Parent(object):
__priv = 'private'
Line 703 ⟶ 994:
inspect.getmembers(chld)
#[('__class__', <class '__main__.Child'>), ..., ('args', (0, 'I', 'two')), ('args_bleh', "(0, 'I', 'two') bleh"), ('doNothing', <bound method Child.doNothing of Child(chld, 0, 'I', 'two')>), ('doStuff', <bound method Child.doStuff of Child(chld, 0, 'I', 'two')>), ('name', 'chld'), ('name_bleh', 'chld bleh'), ('own', "chld's own"), ('own_bleh', "chld's own bleh"), ('reBleh', <_sre.SRE_Pattern object at 0x10067bd20>), ('reBleh_bleh', '<_sre.SRE_Pattern object at 0x10067bd20> bleh')]
</syntaxhighlight>
</lang>
 
=={{header|Raku}}==
(formerly Perl 6)
 
You can get a list of an object's attributes (instance variables) using <tt>.^attributes</tt>, which is part of the [https://docs.raku.org/type/Metamodel$COLON$COLONClassHOW Meta Object Protocol]..<br>
Each is represented as an <tt>Attribute</tt> object that contains a bunch of info:
 
<syntaxhighlight lang="raku" line>class Foo {
has $!a = now;
has Str $.b;
has Int $.c is rw;
}
 
my $object = Foo.new: b => "Hello", c => 42;
 
for $object.^attributes {
say join ", ", .name, .readonly, .container.^name, .get_value($object);
}</syntaxhighlight>
 
{{out}}
<pre>
$!a, True, Any, Instant:1470517602.295992
$!b, True, Str, Hello
$!c, False, Int, 42
</pre>
 
Public attributes (in this case, <tt>$.b</tt> and <tt>$.c</tt>) are really just attributes for which the compiler also auto-generates a method of the same name. See [[Reflection/List_methods#Raku]].
 
=={{header|REXX}}==
Line 719 ⟶ 1,037:
 
A simplistic example:
<langsyntaxhighlight lang="rexx">j=2
abc.j= -4.12
 
 
say 'variable abc.2 (length' length(abc.2)')=' abc.2</langsyntaxhighlight>
<br><br>
===version 2===
<langsyntaxhighlight lang="rexx">/* REXX shows the "equivalent" to PL/I's PUT DATA for a simple variable */
/* put_data2('a.') to show all a.tail values isn't that easy :-) */
j=2
Line 736 ⟶ 1,054:
put_data:
Parse Arg variable
return(variable'='''value(variable)'''')</langsyntaxhighlight>
{{out}}
<pre>abc.2='-4.12'
Line 742 ⟶ 1,060:
 
=={{header|Ruby}}==
<langsyntaxhighlight lang="ruby">class Foo
@@xyz = nil
def initialize(name, age)
Line 770 ⟶ 1,088:
p Foo.class_variable_get(:@@xyz) #=> :xyz
p Foo.class_variable_set(:@@abc, 123) #=> 123
p Foo.class_variables #=> [:@@xyz, :@@abc]</langsyntaxhighlight>
 
=={{header|Scala}}==
===Java Interoperability===
{{Out}}Best seen running in your browser [https://scastie.scala-lang.org/MdkPxH6yTlS4W8TaXYxSgA Scastie (remote JVM)].
<langsyntaxhighlight Scalalang="scala">object ListProperties extends App {
private val obj = new {
val examplePublicField: Int = 42
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println("\nAll declared fields (excluding inherited):")
clazz.getDeclaredFields.foreach(f => println(s"${f}}"))
}</langsyntaxhighlight>
 
=={{header|Smalltalk}}==
for names of slots defined in the class (excludes inherited):
<syntaxhighlight lang="smalltalk">someObject class instVarNames</syntaxhighlight>
for all slot names (incl. inherited):
<syntaxhighlight lang="text">someObject class allInstVarNames</syntaxhighlight>
to get a Dictionary (aka. HashTable) mapping names to values:
<syntaxhighlight lang="text">someObject class allInstVarNames collect:[:nm | nm -> (someObject instVarNamed:nm)] as:Dictionary</syntaxhighlight>
 
A class can make this a secret by redefining #instVar access to eg. raise an exception.
Notice: this is not considered good Smalltalk style - it should be used by debuggers and object inspectors only, except for special frameworks (such as code generators etc.).
 
=={{header|Tcl}}==
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For objects supporting this protocol, you can list all options by invoking the <tt>configure</tt> method without arguments (result split over multiple lines for readability):
<langsyntaxhighlight Tcllang="tcl">% package require Tk
8.6.5
% . configure
Line 803 ⟶ 1,132:
{-highlightcolor highlightColor HighlightColor #000000 #000000}
{-highlightthickness highlightThickness HighlightThickness 0 0} {-padx padX Pad 0 0} {-pady padY Pad 0 0}
{-takefocus takeFocus TakeFocus 0 0} {-visual visual Visual {} {}} {-width width Width 0 0}</langsyntaxhighlight>
 
Two-element sublists (eg <tt>-bd -borderwidth</tt>) represent aliases, and five-element sublists are of the form <tt>{optionName dbName dbClass defaultValue currentValue}</tt>. <tt>dbName</tt> and <tt>dbClass</tt> are related to how the option is specified in the <i>option database</i>.
Line 809 ⟶ 1,138:
Simply listing the option names is like this:
 
<langsyntaxhighlight Tcllang="tcl">% lmap o [. configure] {if {[llength $o] == 2} continue else {lindex $o 0}}
-borderwidth -class -menu -relief -screen -use -background -colormap -container -cursor -height
-highlightbackground -highlightcolor -highlightthickness -padx -pady -takefocus -visual -width</langsyntaxhighlight>
 
=={{header|Visual Basic .NET}}==
{{trans|C#}}
<langsyntaxhighlight lang="vbnet">Imports System.Reflection
 
Module Module1
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End Sub
 
End Module</langsyntaxhighlight>
{{out}}
<pre>{ Name = PublicNumber, Value = 4 }
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{ Name = _PublicNumber, Value = 4 }
{ Name = _PrivateNumber, Value = 2 }</pre>
 
=={{header|Wren}}==
Wren doesn't currently have reflection as such but it's possible to identify a class's properties and list them at runtime by placing a suitable attribute on the class.
 
Note that, since attributes are stored internally as a map, the order in which the property names appear is undefined.
<syntaxhighlight lang="wren">#! instance_methods(m, n, o)
#! instance_properties(p, q, r)
class C {
construct new() {}
 
m() {}
 
n() {}
 
o() {}
p {}
 
q {}
r {}
}
 
var c = C.new() // create an object of type C
System.print("List of properties available for object 'c':")
for (property in c.type.attributes.self["instance_properties"]) System.print(property.key)</syntaxhighlight>
 
{{out}}
<pre>
List of properties available for object 'c':
r
q
p
</pre>
 
=={{header|zkl}}==
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Every object has a "properties" method, which returns a list of property names [for that object].
<langsyntaxhighlight lang="zkl">properties:=List.properties;
properties.println();
List(1,2,3).property(properties[0]).println(); // get value
List(1,2,3).Property(properties[0])().println(); // method that gets value
List(1,2,3).BaseClass(properties[0]).println(); // another way to get value</langsyntaxhighlight>
{{out}}
<pre>
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