Idiomatically determine all the characters that can be used for symbols: Difference between revisions
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Kotlin Identifier ignorable: [0][1][2][3][4][5][6][7][8][14][15][16][17][18][19][20][21][22][23][24][25][26][27][127][128]...
</pre>
=={{header|Ol}}==
Absolutely any Unicode or ANSI character can be used as part of symbol name. There only some limitations in form of symbol declaration.
1. Direct symbol declaration (in form of quote or ') must not be started from control codes (first 32 characters), numbers and @. Next characters in symbol must not be control code neither @.
2. Direct symbol declaration (in form of ||) must not contain character |.
3. Functional symbol creation (in form of string->symbol) have no any limitations.
=={{header|ooRexx}}==
| |||
Revision as of 19:54, 4 September 2019
You are encouraged to solve this task according to the task description, using any language you may know.
Idiomatically determine all the characters that can be used for symbols. The word symbols is meant things like names of variables, procedures (i.e., named fragments of programs, functions, subroutines, routines), statement labels, events or conditions, and in general, anything a computer programmer can choose to name, but not being restricted to this list. Identifiers might be another name for symbols.
The method should find the characters regardless of the hardware architecture that is being used (ASCII, EBCDIC, or other).
- Task requirements
Display the set of all the characters that can be used for symbols which can be used (allowed) by the computer program. You may want to mention what hardware architecture is being used, and if applicable, the operating system.
Note that most languages have additional restrictions on what characters can't be used for the first character of a variable or statement label, for instance. These type of restrictions needn't be addressed here (but can be mentioned).
- See also
AWK
<lang AWK>
- syntax: GAWK -f IDIOMATICALLY_DETERMINE_ALL_THE_CHARACTERS_THAT_CAN_BE_USED_FOR_SYMBOLS.AWK
BEGIN {
fn = "TEMP.AWK"
cmd = sprintf("GAWK -f %s 2>NUL",fn)
for (i=0; i<=255; i++) {
c = sprintf("%c",i)
if (c ~ /\x09|\x0D|\x0A|\x20/) { ng++; continue } # tab,CR,LF,space
(run(c) == 0) ? (ok1 = ok1 c) : (ng1 = ng1 c) # 1st character
(run("_" c) == 0) ? (ok2 = ok2 c) : (ng2 = ng2 c) # 2nd..nth character
}
printf("1st character: %d NG, %d OK %s\n",length(ng1)+ng,length(ok1),ok1)
printf("2nd..nth char: %d NG, %d OK %s\n",length(ng2)+ng,length(ok2),ok2)
exit(0)
} function run(c, rc) {
printf("BEGIN{%s+=0}\n",c) >fn
close(fn)
rc = system(cmd)
return(rc)
} </lang>
output:
1st character: 203 NG, 53 OK ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz 2nd..nth char: 193 NG, 63 OK 0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz
F#
Well, if the purpose of this task is to determine what can be used as an identifier then in F# anything so long as you enclose it in double backticks so: <lang fsharp> let ``+`` = 5 printfn "%d" ``+`` </lang>
- Output:
5
Is this idiotmatically determined?
Factor
<lang factor>USING: parser see ; \ scan-word-name see</lang>
- Output:
: scan-word-name ( -- string )
scan-token dup "\"" = [ t ] [ dup string>number ] if
[ invalid-word-name ] when ;
From this code we can see that any characters may be used in an identifier unless it parses as a string or a number.
Go
Go allows the underscore, letters, and digits, with "letters" and "digits" defined by Unicode. The first character must be the underscore or a letter. To be exported, the first character must be an upper case letter, again as defined by Unicode. <lang go>package main
import ( "fmt" "unicode" )
func main() { fmt.Println("Unicode version: ", unicode.Version) fmt.Println() fmt.Println("Underscore: _") fmt.Println("ASCII digits: 0123456789") fmt.Println("ASCII letters: ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz") showRange("Unicode digits: ", unicode.Digit) showRange("Unicode letters: ", unicode.Letter) }
const Ω = 52
var n int var ряд, 广度一六 int
func showRange(hdr string, rt *unicode.RangeTable) { fmt.Print(hdr) n = 0 r16 := rt.R16 for r16[0].Hi < 128 { r16 = r16[1:] } for _, rng := range r16 { for r := rng.Lo; r <= rng.Hi; r += rng.Stride { fmt.Print(string(r)) n++ if n == Ω { fmt.Println("...") return } } } fmt.Println() for _, rng := range rt.R32 { for r := rng.Lo; r <= rng.Hi; r += rng.Stride { fmt.Print(string(r)) n++ if n == Ω { fmt.Println("...") return } } } fmt.Println() }</lang>
- Output:
Unicode version: 7.0.0 Underscore: _ ASCII digits: 0123456789 ASCII letters: ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz Unicode digits: ٠١٢٣٤٥٦٧٨٩۰۱۲۳۴۵۶۷۸۹߀߁߂߃߄߅߆߇߈߉०१२३४५६७८९০১২৩৪৫৬৭৮৯੦੧... Unicode letters: ªµºÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñ...
J
J is defined in terms of ascii, but that would not prevent it from being ported to other environments. But we can still use J's parser to determine if a specific character combination is a single, legal word:
<lang J> a.#~1=#@;: ::0:"1 'b',.a.,.'c' 0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz</lang>
Here, a. is the set of chararacters we are testing. We prefix each of these with an arbitrary letter, and suffix each with an arbitrary character and then try counting how many parsed tokens are formed by the result. If the token count is 1, then that character was a legal word-forming character.
Of course, we also only need to do this once. Once we have a set of these characters, it's faster and easier to use a set membership test on the characters themselves than on the expression which generates them.
Java
<lang java>import java.util.function.IntPredicate; import java.util.stream.IntStream;
public class Test {
public static void main(String[] args) throws Exception {
print("Java Identifier start: ", 0, 0x10FFFF, 72,
Character::isJavaIdentifierStart, "%c");
print("Java Identifier part: ", 0, 0x10FFFF, 25,
Character::isJavaIdentifierPart, "[%d]");
print("Identifier ignorable: ", 0, 0x10FFFF, 25,
Character::isIdentifierIgnorable, "[%d]");
print("Unicode Identifier start: ", 0, 0x10FFFF, 72,
Character::isUnicodeIdentifierStart, "%c");
print("Unicode Identifier part : ", 0, 0x10FFFF, 25,
Character::isUnicodeIdentifierPart, "[%d]");
}
static void print(String msg, int start, int end, int limit,
IntPredicate p, String fmt) {
System.out.print(msg);
IntStream.rangeClosed(start, end)
.filter(p)
.limit(limit)
.forEach(cp -> System.out.printf(fmt, cp));
System.out.println("...");
}
}</lang>
Java Identifier start: $ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz¢£¤¥ªµºÀÁÂÃÄÅÆÇÈÉÊ... Java Identifier part: [0][1][2][3][4][5][6][7][8][14][15][16][17][18][19][20][21][22][23][24][25][26][27][36][48]... Java Identifier ignorable: [0][1][2][3][4][5][6][7][8][14][15][16][17][18][19][20][21][22][23][24][25][26][27][127][128]... Unicode Identifier start: ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyzªµºÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐ... Unicode Identifier part: [0][1][2][3][4][5][6][7][8][14][15][16][17][18][19][20][21][22][23][24][25][26][27][48][49]...
jq
jq identifiers
Excluding key names from consideration, in jq 1.4 the set of characters that can be used in jq identifiers corresponds to the regex: [A-Za-z0-9$_]. Thus, assuming the availability of test/1 as a builtin, the test in jq for a valid identifier character is: test("[A-Za-z0-9$_]").
To generate a string of such characters idiomatically: <lang jq>[range(0;128) | [.] | implode | select(test("[A-Za-z0-9$_]"))] | add</lang>
jq 1.5 also allows ":" as a joining character in the form "module::name".
JSON key names
Any JSON string can be used as a key. Accordingly, some characters must be entered as escaped character sequences, e.g. \u0000 for NUL, \\ for backslash, etc. Thus any Unicode character except for the control characters can appear in a jq key. Therefore, assuming the availability in jq of the test/1 builtin, the test in jq for whether a character can appear literally in a jq identifier or key is: <lang jq>test("[^\u0000-\u0007F]")</lang>
Symbols
The following function screens for characters by "\p" class: <lang jq>def is_character(class):
test( "\\p{" + class + "}" );</lang>
For example, to test whether a character is a Unicode letter, symbol or numeric character: <lang jq>is_character("L") or is_character("S") or is_character("N")</lang>
An efficient way to count the number of Unicode characters within a character class is to use the technique illustrated by the following function: <lang jq>def count(class; m; n):
reduce (range(m;n) | [.] | implode | select( test( "\\p{" + class + "}" ))) as $i
(0; . + 1);</lang>
For example the number of Unicode "symbol" characters can be obtained by evaluating: <lang jq>count("S"; 0; 1114112)</lang> The result is 3958.
Julia
Julia allows almost any Unicode character as a symbol if it is not a reserved operator symbol and, if numeric, if it is not the first letter of a symbol name.
For example, x2 is a valid identifier, but 2x is not-- it is interpreted as 2 times the identifier x. In Julia, the Symbol() function turns a string into a symbolic token. So, for example: <lang julia> for i in 1:0x200000 - 1
Symbol("x" * Char(i))
end </lang>
When run, this loop runs without error up to 0x200000 but not at Unicode symbol numbered 0x200000.
Kotlin
According to the Kotlin grammar, the rules regarding which characters can appear in symbols (or identifiers as we usually call them) are the same as in Java, namely:
1. An identifier is a sequence of any number of unicode letters or digits, other than a reserved word.
2. Identifiers are case sensitive.
3. The first character must be a letter, an underscore or a $ sign. Subsequent characters can include digits and certain control characters as well though the latter are ignored for identifier matching purposes.
However, in practice, identifiers which include a $ symbol or control characters don't compile unless (in the case of $) the entire identifier is enclosed in back-ticks. The use of this device also allows one to use a reserved word or many otherwise prohibited unicode characters in an identifier including spaces and dashes.
A Kotlin label name is a valid identifier followed by an @ symbol and an annotation name is an identifier preceded by an @ symbol. <lang scala>// version 1.1.4-3
typealias CharPredicate = (Char) -> Boolean
fun printChars(msg: String, start: Int, end: Int, limit: Int, p: CharPredicate, asInt: Boolean) {
print(msg)
(start until end).map { it.toChar() }
.filter { p(it) }
.take(limit)
.forEach { print(if (asInt) "[${it.toInt()}]" else it) }
println("...")
}
fun main(args: Array<String>) {
printChars("Kotlin Identifier start: ", 0, 0x10FFFF, 72,
Char::isJavaIdentifierStart, false)
printChars("Kotlin Identifier part: ", 0, 0x10FFFF, 25,
Character::isJavaIdentifierPart, true)
printChars("Kotlin Identifier ignorable: ", 0, 0x10FFFF, 25,
Character::isIdentifierIgnorable, true)
}</lang>
- Output:
Kotlin Identifier start: $ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz¢£¤¥ªµºÀÁÂÃÄÅÆÇÈÉÊ... Kotlin Identifier part: [0][1][2][3][4][5][6][7][8][14][15][16][17][18][19][20][21][22][23][24][25][26][27][36][48]... Kotlin Identifier ignorable: [0][1][2][3][4][5][6][7][8][14][15][16][17][18][19][20][21][22][23][24][25][26][27][127][128]...
Ol
Absolutely any Unicode or ANSI character can be used as part of symbol name. There only some limitations in form of symbol declaration.
1. Direct symbol declaration (in form of quote or ') must not be started from control codes (first 32 characters), numbers and @. Next characters in symbol must not be control code neither @.
2. Direct symbol declaration (in form of ||) must not contain character |.
3. Functional symbol creation (in form of string->symbol) have no any limitations.
ooRexx
Although this program does not use any feature that is not in Classic Rexx, it is included here to show what characters are valid for symbols in ooRexx. <lang oorexx>/*REXX program determines what characters are valid for REXX symbols.*/ /* copied from REXX version 2 */ Parse Version v Say v symbol_characters= /* start with no chars */ do j=0 To 255 /* loop through all the chars.*/
c=d2c(j) /* convert number to character*/ if datatype(c,'S') then /* Symbol char */ symbol_characters=symbol_characters || c /* add to list. */ end
say 'symbol characters:' symbol_characters /*display all */</lang>
- Output:
REXX-ooRexx_4.2.0(MT)_32-bit 6.04 22 Feb 2014 symbol characters: !.0123456789?ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz
PARI/GP
The only symbols that can be used in variable names (including function names as a special case) are a-z, A-Z, 0-9, and the underscore. Additionally, the first character must be a letter. (That is, they must match this regex: [a-zA-Z][a-zA-Z0-9_]*.)
<lang parigp>v=concat(concat([48..57],[65..90]),concat([97..122],95));
apply(Strchr,v)</lang>
- Output:
%1 = ["0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z", "a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z", "_"]
Perl
<lang perl># When not using the use utf8 pragma, any word character in the ASCII range is allowed.
- the loop below returns: 0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz
for $i (0..0x7f) {
$c = chr($i); print $c if $c =~ /\w/;
}
- When 'use utf8' is in force, the same holds true, but the Unicode-aware version of the 'word-character' test is used.
- not supplying output, too much of it
use utf8; binmode STDOUT, ":utf8"; for (0..0x1ffff) {
$c = chr($_);
print $c if $c =~ /\p{Word}/;
}</lang>
Perl 6
Any Unicode character or combination of characters can be used for symbols in Perl 6. Here's some counting rods and some cuneiform: <lang perl6>sub postfix:<𒋦>($n) { say "$n trilobites" }
sub term:<𝍧> { unival('𝍧') }
𝍧𒋦</lang>
- Output:
8 trilobites
And here is a Zalgo-text symbol:
<lang perl6>sub Z̧̔ͩ͌͑̉̎A̢̲̙̮̹̮͍̎L̔ͧ́͆G̰̬͎͔̱̅ͣͫO͙̔ͣ̈́̈̽̎ͣ ($n) { say "$n COMES" }
Z̧̔ͩ͌͑̉̎A̢̲̙̮̹̮͍̎L̔ͧ́͆G̰̬͎͔̱̅ͣͫO͙̔ͣ̈́̈̽̎ͣ 'HE'</lang>
- Output:
HE COMES
Of course, as in other languages, most of the characters you'll typically see in names are going to be alphanumerics from ASCII (or maybe Unicode), but that's a convention, not a limitation, due to the syntactic category notation demonstrated above, which can introduce any sequence of characters as a term or operator.
Actually, the above is a slight prevarication. The syntactic category notation does not allow you to use whitespace in the definition of a new symbol. But that leaves many more characters allowed than not allowed. Hence, it is much easier to enumerate the characters that cannot be used in symbols: <lang perl6>say .fmt("%4x"),"\t", uniname($_)
if uniprop($_,'Z')
for 0..0x1ffff;</lang>
- Output:
20 SPACE a0 NO-BREAK SPACE 1680 OGHAM SPACE MARK 2000 EN QUAD 2001 EM QUAD 2002 EN SPACE 2003 EM SPACE 2004 THREE-PER-EM SPACE 2005 FOUR-PER-EM SPACE 2006 SIX-PER-EM SPACE 2007 FIGURE SPACE 2008 PUNCTUATION SPACE 2009 THIN SPACE 200a HAIR SPACE 2028 LINE SEPARATOR 2029 PARAGRAPH SEPARATOR 202f NARROW NO-BREAK SPACE 205f MEDIUM MATHEMATICAL SPACE 3000 IDEOGRAPHIC SPACE
We enforce the whitespace restriction to prevent insanity in the readers of programs. That being said, even the whitespace restriction is arbitrary, and can be bypassed by deriving a new grammar and switching to it. We view all other languages as dialects of Perl 6, even the insane ones. :-)
Phix
Translation of AWK, extended with separation of ansi and utf8 handling <lang Phix>function run(string ident)
integer fn = open("test.exw","w")
printf(fn,"object %s",ident)
close(fn)
return system_exec("p -batch test.exw")
end function
function check(integer lo, hi)
string ok1 = "", ok2 = ""
integer ng1 = 0, ng2 = 0
for ch=lo to hi do
printf(1,"%d/%d...\r",{ch,hi})
if find(ch,"\t\r\n \0\x1A;") then
ng1 += 1
ng2 += 1
else
string c = sprintf("%c",ch)
if run(c)==0 then ok1 &= c else ng1 += 1 end if
if run("_"&c)==0 then ok2 &= c else ng2 += 1 end if
end if
end for
return {{ng1,length(ok1),ok1},
{ng2,length(ok2),ok2}}
end function
sequence r = check(0,127) printf(1,"ansi characters:\n===============\n") printf(1,"1st character: %d bad, %d OK %s\n",r[1]) printf(1,"2nd..nth char: %d bad, %d OK %s\n\n",r[2]) r = check(128,255) integer ok8 = 0, ng8 = 0 for i=#80 to #10FFFF do
if i<#D800 or i>#DFFF then
printf(1,"#%x/#10FFFF...\r",i)
string utf8 = utf32_to_utf8({i})
bool ok = true
if not find(utf8[1],r[1][3]) then
ok = false
else
for j=2 to length(utf8) do
if not find(utf8[j],r[2][3]) then
ok = false
exit
end if
end for
end if
if ok then
ok8 += 1
else
ng8 += 1
end if
end if
end for printf(1,"utf8 characters: \n===============\n") printf(1,"bad:%,d, good:%,d\n",{ng8,ok8})</lang>
- Output:
ansi characters: =============== 1st character: 75 bad, 53 OK ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz 2nd..nth char: 65 bad, 63 OK 0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz utf8 characters: =============== bad:0, good:1,111,936
Note that versions prior to 0.8.1 only permit a mere 48 utf8 characters, running the same code on 0.7.9 gave me
utf8 characters: =============== bad:1,111,888, good:48
Python
See String class isidentifier.
Racket
Symbols in the Racket Guide states that:
Any string (i.e., any character sequence) can be supplied to
string->symbolto obtain the corresponding symbol.
Reading Symbols defines what symbols can be "read" without needing quoting.
The docuementation for
integer->char
says that a character must lie in the ranges: 0 to 55295, and 57344 to 1114111.
That's too much to be printing out here... call (main) yourself, at home.
<lang racket>#lang racket
- Symbols that don't need to be specially quoted
(printf "~s~%" '(a a-z 3rd ...---... .hidden-files-look-like-this))
- Symbols that do need to be specially quoted
(define bar-sym-list
`(|3| |i have a space| |i've got a quote in me| |i'm not a "dot on my own", but my neighbour is!| |.| ,(string->symbol "\u03bb") ,(string->symbol "my characters aren't even mapped in unicode \U10e443")))
(printf "~s~%" bar-sym-list) (printf "~a~%" bar-sym-list)
(define (main)
(for
((c (sequence-map
integer->char
(in-sequences (in-range 0 (add1 55295))
(in-range 57344 (add1 1114111)))))
(i (in-naturals 1)))
(when (zero? (modulo i 80)) (newline))
(display (list->string (list c)))))
</lang>
- Output:
(a a-z 3rd ...---... .hidden-files-look-like-this) (|3| |i have a space| |i've got a quote in me| |i'm not a "dot on my own", but my neighbour is!| |.| λ |my characters aren't even mapped in unicode |) (3 i have a space i've got a quote in me i'm not a "dot on my own", but my neighbour is! . λ my characters aren't even mapped in unicode )
The output to (main) is massive, and probably not dissimilar to Tcl's (anyone want to compare?)
REXX
version 1
<lang rexx>/*REXX program determines what characters are valid for REXX symbols. */ @= /*set symbol characters " " */
do j=0 for 2**8 /*traipse through all the chars. */ _=d2c(j) /*convert decimal number to char.*/ if datatype(_,'S') then @=@ || _ /*Symbol char? Then add to list.*/ end /*j*/ /* [↑] put some chars into a list*/
say ' symbol characters: ' @ /*display all symbol characters.*/
/*stick a fork in it, we're done.*/</lang>
Programming note: REXX allows any symbol to begin a (statement) label, but variables can't begin with a period (.) or a numeric digit.
All examples below were executed on a (ASCII) PC using Windows/XP and Windows/7 with code page 437 in a DOS window.
Using PC/REXX
Using Personal REXX
Using Regina (versions 3.2 ───► 3.82)
output
symbol characters: !#$.0123456789?@ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz
Using R4
output
symbol characters: !#$.0123456789?@ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyzÇüéâäàåçêëèïîìÄÅÉæÆôöòûùÿÖÜ¢£áíóúñÑ╡╢╖─╞╟╨╤╥╙╘╒╓╫╪▐αßΓπΣσµτΦΘΩδ∞φ
Using ROO
output
symbol characters: !#$.0123456789?@ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyzÇüéâäàåçêëèïîìÄÅÉæÆôöòûùÿÖÜ¢£áíóúñÑ╡╢╖╞╟╨╤╥╙╘╒╓╫╪▐αßΓπΣσµτΦΘΩδ∞φ
version 2 ooRexx compatible
Because version 1 does not work correctly with ooRexx - showing this error message:
2 *-* @
Error 13 running D:\v1.rex line 2: Invalid character in program
Error 13.1: Incorrect character in program "@" ('40'X)
I've added version 2 which should work correctly for all Rexx interpreters and compilers <lang rexx>/*REXX program determines what characters are valid for REXX symbols.*/ /* version 1 adapted for general acceptance */ Parse Version v Say v symbol_characters= /* start with no chars */ do j=0 To 255 /* loop through all the chars.*/
c=d2c(j) /* convert number to character*/ if datatype(c,'S') then /* Symbol char */ symbol_characters=symbol_characters || c /* add to list. */ end
say 'symbol characters:' symbol_characters /*display all */ </lang>
- Output:
for some interpreters
Note that $#@ are not valid symbol characters for ooRexx.
REXX-ooRexx_4.2.0(MT)_32-bit 6.04 22 Feb 2014 symbol characters: !.0123456789?ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz REXX-Regina_3.8.2(MT) 5.00 22 Jun 2014 symbol characters: !#$.0123456789?@ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz
Scala
- Output:
Best seen running in your browser either by ScalaFiddle (ES aka JavaScript, non JVM) or Scastie (remote JVM).
<lang Scala>object IdiomaticallyDetermineSymbols extends App {
private def print(msg: String, limit: Int, p: Int => Boolean, fmt: String) = println(msg + (0 to 0x10FFFF).filter(p).take(limit).map(fmt.format(_)).mkString + "...")
print("Java Identifier start: ", 72, cp => Character.isJavaIdentifierStart(cp), "%c")
print("Java Identifier part: ", 25, cp => Character.isJavaIdentifierPart(cp), "[%d]")
print("Identifier ignorable: ", 25, cp => Character.isIdentifierIgnorable(cp), "[%d]")
print("Unicode Identifier start: ", 72, cp => Character.isUnicodeIdentifierStart(cp), "%c")
print("Unicode Identifier part : ", 25, cp => Character.isUnicodeIdentifierPart(cp), "[%d]")
}</lang>
Tcl
Tcl permits any character to be used in a variable or command name (subject to the restriction that :: is a namespace separator and, for variables only, a (…) sequence is an array reference). The set of characters that can be used after $ is more restricted, excluding many non-letter-like symbols, but still large. It is recommended practice to only use ASCII characters for variable names as this makes scripts more resistant to the majority of encoding problems when transporting them between systems, but the language does not itself impose such a restriction.
<lang tcl>for {set c 0;set printed 0;set special {}} {$c <= 0xffff} {incr c} {
set ch [format "%c" $c]
set v "_${ch}_"
#puts "testing variable named $v"
if {[catch {set $v $c; set $v} msg] || $msg ne $c} {
puts [format "\\u%04x illegal in names" $c] incr printed
} elseif {[catch {subst $$v} msg] == 0 && $msg eq $c} {
lappend special $ch
}
} if {$printed == 0} {
puts "All Unicode characters legal in names"
} puts "Characters legal after \$: $special"</lang>
- Output:
Only the first 256 characters are displayed:
All Unicode characters legal in names Characters legal after $: 0 1 2 3 4 5 6 7 8 9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z _ a b c d e f g h i j k l m n o p q r s t u v w x y z ª µ º À Á Â Ã Ä Å Æ Ç È É Ê Ë Ì Í Î Ï Ð Ñ Ò Ó Ô Õ Ö Ø Ù Ú Û Ü Ý Þ ß à á â ã ä å æ ç è é ê ë ì í î ï ð ñ ò ó ô õ ö ø ù ú û ü ý þ ÿ İ ı IJ ij Ĵ ĵ Ķ ķ ĸ Ĺ Ł ł Ń ń Ņ ņ Ň ň ʼn Ŋ ŋ Ō ō Ŏ ŏ Ő ő Œ œ Ŕ ŕ Ŗ ŗ Ř ř Ś ş š Ţ ţ Ť ť Ŧ ŧ Ũ ũ Ū ū Ŭ ŭ Ů ů Ű ű Ų ų Ŵ ŵ Ŷ ŷ Ÿ Ź ź ƪ Ƶ ƺ ǀ ǁ ǂ ǃ DŽ Dž dž LJ Lj lj NJ Nj nj Ǎ ǎ Ǐ ǐ Ǒ ǒ Ǔ ǔ Ǖ ǖ ǘ Ǚ ǚ Ǜ ǜ ǝ Ǟ ǟ Ǡ ǡ Ǣ ǣ Ǥ ǥ Ǧ ǧ Ǩ ǩ Ǫ ǫ Ǭ ǭ Ǯ ǯ ǰ DZ Dz dz Ǵ ǵ Ƕ Ǹ ǹ Ǻ ǻ Ǽ ǽ Ǿ ǿ ...
zkl
zkl only supports ASCII, although other character sets might be finessed. <lang zkl>[0..255].filter(fcn(n){
try{ Compiler.Compiler.compileText("var "+n.text) }
catch{ False }
}).apply("text").concat()</lang>
- Output:
<compiler noise> ;ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz
This code works by compiling "var <char>". Since "var ;" is valid syntax (dead code), ";" is a false positive. We could also use "fcn <char>{}" but "fcn {}" is lambda syntax, so space would be a false positive. "_" is excluded because it is not valid variable name although it can be anywhere in a multi-character name.