Unicode variable names: Difference between revisions

{{task|Unicode}}

# Describe, and give a pointer to documentation on your languages use of characters ''beyond'' those of the ASCII character set in the naming of variables.

# Show how to:

* [[Case-sensitivity of identifiers]]

<br><br>

 

=={{header|8th}}==

-- [http://8th-dev.com/local.html Writing localized applications with 8th]

 

1 var, Δ

 

الوداع

 

 

=={{header|ACL2}}==

Variables in ACL2 cannot be modified in place.

 

=={{header|Ada}}==

As of Ada 2005, all source code can be made of up to 32bit characters.

Unless you have made it a default, GNAT would require the -gnatW8 flag to understand you are using UTF8 for the code below, other encodings are possible.

procedure main is

Δ : Integer;

Δ := Δ + 1;

Ada.Text_IO.Put_Line (Δ'Img);

{{out}}

<pre> 42</pre>

=={{header|ALGOL 68}}==

The definition of Algol 68 is character set independent. Not only variables may be represented in Unicode, all other language elements may be so represented. All that is required is that the representation language must be capable of being translated unambigously back and forth into the reference language.

 

''Russian/Soviet example: In English Algol68's reverent case statement reads '''case''' ~ '''in''' ~ '''out''' ~ '''esac''', in Cyrillic this reads '''выб''' ~ '''в''' ~ '''либо''' ~ '''быв'''.''

 

=={{header|AutoHotkey}}==

Documentation: http://www.autohotkey.net/~Lexikos/AutoHotkey_L/docs/Variables.htm

{{works with|AutoHotkey_L}}

Δ++

 

=={{header|BaCon}}==

This is a port from the C example. As mentioned there, C has limited support for Unicode variable names which is specified in the C standard, and BaCon, being a Basic-to-C converter, therefore has the same restrictions. The below example works with the CLang compiler.

 

DECLARE Δ TYPE int

INCR Δ

 

{{out}}

<pre>

=={{header|Bracmat}}==

Bracmat allows any sequence of non-zero bytes as symbol and therefore, as variable name. Even the empty string is a variable, though a special one. If a symbol/variable name contains characters that have special meaning (operators, prefixes, parentheses, braces and the semicolon) it may be necessary to enclose it in quotes. Other special characters must be escaped C-style. See bracmat.html in the git-repo. The example below requires a terminal that supports UTF-8 encoded characters.

& 1+!Δ:?Δ

& out$("Δ:" !Δ)

Output:

<pre>Δ: 2</pre>

 

=={{header|C}}==

 

 

#include<stdio.h>

 

int main() {

Δ++;

printf("%d",Δ);

return 0;

Output:

<pre>

=={{header|C sharp|C#}}==

Section 2.4.2 of the [http://go.microsoft.com/fwlink/?LinkId=199552 C# Language Specification] gives rules for identifiers. They correspond exactly to those recommended by the [http://unicode.org/reports/tr31/ Unicode Standard Annex 31], except that underscore is allowed as an initial character (as is traditional in the C programming language), Unicode escape sequences are permitted in identifiers, and the "@" character is allowed as a prefix to enable keywords to be used as identifiers.

{

static void Main()

System.Console.WriteLine(Δ);

}

{{out}}

<pre>2</pre>

 

=={{header|Clojure}}==

That being said, it is not currently enforced, so while you probably shouldn't, you technically can.

 

{{out}}

<pre>2</pre>

 

=={{header|Common Lisp}}==

{{out}}

<pre>2</pre>

=={{header|D}}==

D source files support four character encodings: ASCII, UTF-8, UTF-16 and UTF-32.

 

void main() {

Δ++;

writeln(Δ);

{{out}}

<pre>2</pre>

=={{header|Delphi}}==

For more information about naming identifiers (including variables) visit: [http://docwiki.embarcadero.com/RADStudio/en/Identifiers Identifiers in Delphi]

program UnicodeVariableName;

 

Writeln(Δ);

Readln;

 

=={{header|DWScript}}==

 

Δ := 1;

Inc(Δ);

 

=={{header|EchoLisp}}==

Symbol names can be any string including unicode characters. See the EchoLisp [http://www.echolalie.org/echolisp/help.html#language reference] documentation.

(define ∆-🍒 1) → ∆-🍒

(set! ∆-🍒 (1+ ∆-🍒)) → 2

(printf "🔦 Look at ∆-🍒 : %d" ∆-🍒)

🔦 Look at ∆-🍒 : 2

=={{header|Elena}}==

{

var Δ := 1;

Δ := Δ + 1;

 

=={{header|Emacs Lisp}}==

(setq Δ (1+ Δ))

 

Variables are symbols and symbol names can be any string. Source code <code>.el</code> files can have all usual Emacs coding system specifications to give variables in non-ASCII.

=={{header|F_Sharp|F#}}==

As with C# the [http://research.microsoft.com/en-us/um/cambridge/projects/fsharp/manual/spec.html#_Toc207705761 F# Language Specification] refers to [http://www.unicode.org/reports/tr31/#Default_Identifier_Syntax Unicode Standard Annex #31] for identifier syntax, allowing Unicode letter characters.

Δ <- Δ + 1

 

=={{header|Factor}}==

Variable names can contain any character, inlcuding unicode characters, as long as they don't parse as a string or a number.

[let

1 :> Δ!

Δ 1 + Δ!

Δ .

 

=={{header|Forth}}==

Historically, Forth has worked only in ASCII (going so far as to reserve the eighth bit for symbol smudging), but modern implementations (e.g., Gforth) allow UTF-8 in word names, strings and comments.

1 ∆ !

1 ∆ +!

 

=={{header|FreeBASIC}}==

If one wanted to use a Greek character such as Δ for a variable name, it would therefore have to be spelled out :

 

 

Var delta = 1

delta += 1

Print delta '' 2

 

=={{header|Frink}}==

Frink can use Unicode variable names that meet certain constraints. Variable names that don't meet these constraints can still be parsed and displayed by specifying them as Unicode escapes: [https://frinklang.org/#UnicodeInFrink Unicode Variable Names]

Δ = 1

Δ = Δ + 1

println[Δ]

 

=={{header|Go}}==

Go source encoding is [http://golang.org/doc/go_spec.html#Source_code_representation specified] to be UTF-8. Allowable variable names are specified in the sections [http://golang.org/doc/go_spec.html#Identifiers identifiers] and [http://golang.org/doc/go_spec.html#Exported_identifiers Exported identifiers].

 

import "fmt"

Δ++

fmt.Println(Δ)

{{out}}

<pre>

 

Also, Haskell does not allow mutable variables, so incrementing delta isn't possible. Instead lower case psi was used to store the incremented value of delta since tridents are cool.

where δΔ = 1

 

=={{header|J}}==

 

=={{header|Java}}==

double π = 3.141592;

String 你好 = "hello";

Δ++;

{{out}}

<pre>

 

=={{header|JavaScript}}==

var ĦĔĽĻŎ = "hello";

var 〱〱〱〱 = "too less";

var KingGeorgeⅦ = "Roman numerals.";

 

{{out}}

<pre>

 

However, in practice, the keys of JSON objects can also be used as variable names. For example, in the following expression, "Δ" is in effect set to 1 and then its value is retrieved in the environment in which "Δ" has been set:

 

 

Strictly speaking, variables in jq cannot be incremented (in fact, strictly speaking, jq does not have variables at all), but the equivalent operation is illustrated here:

 

| .["Δ"] += 1 # increment by 1

 

=={{header|Julia}}==

The Julia documentation on

[http://docs.julialang.org/en/latest/manual/variables/#allowed-variable-names allowed variable names] explicitly describes the wide variety of Unicode codepoints that are allowed:

The allowed identifiers also include sub/superscripts and combining characters (e.g. accent marks):

and the Julia interactive shells (and many editors) allow typing these symbols via tab-completion of their LaTeX abbreviations.

 

=={{header|Kotlin}}==

var Δ = 1

Δ++

print(Δ)

 

{{out}}

2

</pre>

 

=={{header|Lingo}}==

Since version 11, in Lingo/Director both native strings and scripts use UTF-8 encoding. Variable names support Unicode characters:

Δ = Δ + 1

put Δ

 

=={{header|LiveCode}}==

In LiveCode 7+ all characters are stored as unicode. This includes variable (container) names, although it does not seem to state this in the LC dictionary.

add 1 to Δ

put Δ

 

=={{header|LOLCODE}}==

The [http://lolcode.com/specs/1.2#variables spec] mandates that identifiers be alphanumeric. However, the fact that [http://lolcode.com/specs/1.2#strings YARNs] are Unicode-aware permits the use of the [http://lolcode.com/proposals/1.3/bukkit2#srs-serious-cast SRS operator] introduced in 1.3 to utilize variables of arbitrary name.

SRS "Δ" R SUM OF SRS ":(394)" AN 1

{{out}}

<pre>2</pre>

Lua 5.3 supports UTF-8 encoding as documented here: https://www.lua.org/manual/5.3/manual.html#6.5 .

However, this support is not strictly necessary for this task so long as the Lua script is edited using a UTF-8 enabled text editor.

∆ = ∆ + 1

{{out}}

<pre>2</pre>

 

=={{header|M2000 Interpreter}}==

Δ=1

Δ++

Print Δ

 

Δ++;

 

=={{header|Nemerle}}==

From the Nemerle [http://nemerle.org/wiki/index.php?title=Lexical_structure_%28ref%29 Reference Manual]: "Programs are written using the Unicode character set, using the UTF-8 encoding."

 

module UnicodeVar

WriteLine($"Δ = $Δ");

}

 

=={{header|NetRexx}}==

The ''NetRexx Language Definition'' section of the NetRexx documentation ([http://netrexx.org/files/nrl3.pdf netrexx.org/files/nrl3.pdf]) describes the character set support within the language.

options replace format comments java crossref symbols nobinary

 

 

return

'''Output:'''

<pre>

 

=={{header|Nim}}==

 

 

=={{header|Objeck}}==

As of 3.2, Objeck supports UTF-8 encoded I/O and stores characters in the runtime's native Unicode format.

class Test {

function : Main(args : String[]) ~ Nil {

}

}

 

=={{header|Ol}}==

Ol fully supports Unicode.

 

(define Δ 1)

(define Δ (+ Δ 1))

(print Δ)

 

{{out}}

2.

<@ ACTICRVAR>Δ</@>

Using what Google Translate says is the Traditional Chinese for 'delta'

<@ ACTICRVAR>三角洲</@>

 

=={{header|Perl}}==

Requires Perl 5.8.1 at the minimum. See http://perldoc.perl.org/utf8.html

 

 

my $Δ = 1;

$Δ++;

 

<code>$</code> sigil can be omitted by using [http://perldoc.perl.org/perlsub.html#Lvalue-subroutines lvalue] subroutine:

 

 

BEGIN {

Δ = 1;

Δ++;

 

or with Perl 5.10 and [http://perldoc.perl.org/functions/state.html state] modifier:

 

use v5.10;

 

Δ = 1;

Δ++;

 

One can have Unicode in identifier or subroutine names and also in package or class names. Use of Unicode for the last two purposes is, due to file and directory names, dependent on the filesystem.

 

=={{header|Phix}}==

Phix does not officially support unicode variable names, however it took me less than 5 minutes (changes, which are now permanent, labelled with "for rosettacode/unicode" in ptok.e and pttree.e, setting charset and identset respectively) to get the following to work, as long as the source file is stored using utf8 with a proper BOM, as supported by Notepad and the included Edita. I will happily add further character ranges as required/requested: I simply don't know what those ranges are, but I believe that no code points in utf8 should overlap existing ascii chars such as +-* etc.

{{out}}

<pre>

 

Documentation: [http://php.net/manual/en/mbstring.php4.req.php mbstring.php4.req], [http://php.net/manual/en/language.variables.basics.php language.variables.basics]

$Δ = 1;

++$Δ;

 

=={{header|PicoLisp}}==

Variables are usually [http://software-lab.de/doc/ref.html#internal-io Internal Symbols], and their names may contain any UTF-8 character except null-bytes. White space, and 11 special characters (see the reference) must be escaped with a backslash. [http://software-lab.de/doc/ref.html#transient-io Transient Symbols] are often used as variables too, they follow the syntax of strings in other languages.

-> 1

: Δ

-> 2

: Δ

 

=={{header|PowerShell}}==

$Δ = 2

$π = 3.14

$π*$Δ

<b>Output:</b>

<pre>

 

=={{header|Prolog}}==

是. % be: means, approximately, "True".

不是 :- \+ 是. % not be: means, approximately, "False". Defined as not 是.

 

% Call test2(1, Result) to have 2 assigned to Result.

 

Putting this into use:

true.

 

 

?- test2(1,Result).

 

=={{header|Python}}==

 

Identifiers are unlimited in length. Case is significant.

>>> Δx += 1

>>> print(Δx)

2

 

=={{header|R}}==

See <code>?assign</code> for details.

 

 

{{out}}

<pre>[1] 2</pre>

Racket has virtually no restrictions on valid characters for identifiers. In particular, Unicode identifiers are supported.

 

#lang racket

 

(printf "Δ = ~s\n" Δ) ; prints "Δ = 2"

 

 

=={{header|Retro}}==

Function and variable names are stored as strings, and UTF-8 is usable, as long as the host system allows it.

 

Note: &nbsp; this REXX program &nbsp; ''only'' &nbsp; works with the &nbsp; '''R4''' &nbsp; or &nbsp; '''ROO''' &nbsp; REXX interpreter under DOS or DOS under Windows.

 

'chcp' 1253 "> NUL" /*ensure we're using correct code page.*/

Δ=1 /*define delta (variable name Δ) to 1*/

Δ=Δ+1 /*bump the delta REXX variable by unity*/

'''output'''

<pre>

 

=={{header|Ring}}==

# Project : Unicode variable names

 

Δ = "Ring Programming Language"

see Δ + nl

Output:

<pre>

=={{header|Ruby}}==

Ruby supports about 100 encodings, the default being UTF-8.

Δ += 1

 

=={{header|Rust}}==

<b>Non-ASCII identifiers are [https://github.com/mozilla/rust/pull/10605 feature gated] since version 0.9</b>

 

#![allow(non_snake_case)]

 

Δ += 1;

println!("{}", Δ);

 

=={{header|S-lang}}==

not just in variable but also function and reference names, and tested under

S-Lang versions 2.0.6 and pre2.3.1-23.

@∆ref++;

}

print(foo∆bar);

print(∆bar);

{{out}}

2

 

=={{header|Scala}}==

val π = 3.141592

val 你好 = "hello"

Δ += 1

 

=={{header|Sidef}}==

Δ += 1;

{{out}}

<pre>2</pre>

Here is how to create a macro, a scalar and a Mata variable named Δ:

 

sca Δ=Δ+1

di Δ

Δ++

Δ

 

=={{header|Swift}}==

let π = 3.141592

let 你好 = "hello"

Δ++

{{out}}

<pre>

 

=={{header|Tcl}}==

incr Δx

However, this script only works smoothly if the “<tt>Δ</tt>” character is in the system's default encoding (thankfully more common than it used to be, as more and more systems use UTF-8 or UTF-16 as their default encodings) so normal Tcl practice is to stick to ASCII for identifier names.

 

It is also possible to encode characters using a <tt>\u''XXXX''</tt> substitution (each <tt>''X''</tt> is a hexadecimal digit), thus the <code>Δx</code> could be replaced throughout above by <code>\u0394x</code>; the result is a variable with exactly the same name as before. Doing this allows a script to be written with just ASCII characters, which tends to maximize portability across platforms.

 

=={{header|Vala}}==

Vala has limited support for Unicode in variable names. This limitation comes from its source-to-source compilation to C.

 

=={{header|zkl}}==

The short answer is zkl identifiers are a small subset of ASCII. This is enforced by the compiler. That said, the VM doesn't particularly care about names (although UTF-8 will cause sorting/etc issues). So ...

klass:= // embryo(names, numFcns, numClasses, numParents, ...)

self.embryo(L("","",delta),0,0,0).cook();

dv:=klass.setVar(0); // which actually gets the var, go figure

dv.inc(); // ie (*ptr)++

{{out}}

<pre>

2

</pre>

{{omit from|AWK}}

{{omit from|BASIC}}

{{omit from|Bc}}

{{omit from|BLAST}}

{{omit from|Dc}}

{{omit from|Erlang|Not yet but planned}}

{{omit from|Free Pascal}}

{{omit from|TUSCRIPT}}

{{omit from|Unicon}}

{{omit from|ZX Spectrum Basic}}