Numeric separator syntax: Difference between revisions
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Several programming languages allow separators in numerals in order to group digits together.
;Task:
Show the numeric separator syntax and describe its specification.
;E.G.:
:* What separators are eligible?
:* Can there be multiple consecutive separators?
:* What position can a separator be in?
:* Etc.
<br><br>
=={{header|11l}}==
The apostrophe, <code>'</code>, is used as a digit separator.
3-digit groups [from the right] should be used in decimal numeric literals.
<syntaxhighlight lang="11l">print(100'000) // correct numeric literal
print(1'00000) // wrong numeric literal</syntaxhighlight>
=={{Header|Ada}}==
The Ada language uses the underscore '_' as a digit separator. The underscore separator must be between digits.
<syntaxhighlight lang="ada">with Ada.Text_IO; use Ada.Text_IO;
with Ada.Float_Text_IO; use Ada.Float_Text_IO;
procedure Main is
type u64 is mod 2**64;
pi : constant Float :=
3.14159_26535_89793_23846_26433_83279_50288_41971_69399_37511;
Trillion : u64 := 1_000_000_000_000;
begin
Put ("pi : ");
Put (Item => pi, Exp => 0, Aft => 7);
New_Line;
Put_Line ("Trillion : " & Trillion'Image);
end Main;</syntaxhighlight>
{{out}}
<pre>
pi : 3.141593
Trillion : 1000000000000
</pre>
=={{header|ALGOL 68}}==
In Algol 68, spaces are not significant in identifiers or numeric literals. This allows spaces to be used as numeric separators.
<br>Single or multiple spaces can be used as desired, it is not necessary to group the digits into blocks of three.
<
INT a = 1 234 567;
REAL b = 3 . 1 4159 26 5 359;
print( ( whole( a, 0 ), " ", fixed( b, - 14, 11 ), newline ) )
END
</syntaxhighlight>
{{out}}
<pre>
1234567 3.14159265359
</pre>
=={{header|Arturo}}==
Arturo does not have numeric separator syntax.
Numbers can be either normal integers (without any separators whatsoever) or floating-point numbers.
<syntaxhighlight lang="rebol">a: 1234567
b: 3.14
print a
print b</syntaxhighlight>
{{out}}
<pre>1234567
3.14</pre>
=={{header|AWK}}==
<syntaxhighlight lang="awk">
# syntax: GAWK -f NUMERIC_SEPARATOR_SYNTAX.AWK
# converted from ALGOL 68
BEGIN {
# AWK lacks numeric separators but can be simulated using white space.
a = 1 234 567
b = 3 "." 1 4159 26 5 359
print(a,b)
exit(0)
}
</syntaxhighlight>
{{out}}
<pre>
1234567 3.14159265359
</pre>
=={{header|C}}==
locale.h provides Localization functions and is part of the C Standard Library. Separating digits in code text was not possible until C23.
<syntaxhighlight lang="c">
#include <locale.h>
#include <stdio.h>
int main()
{
unsigned long long int trillion = 1000000000000;
setlocale(LC_NUMERIC,"");
printf("Locale : %s, One Trillion : %'llu\n", setlocale(LC_CTYPE,NULL),trillion);
return 0;
}
</syntaxhighlight>
Output :
<pre>
[pi@raspberrypi:~/doodles $ ./a.out
Locale : C, One Trillion : 1,000,000,000,000
</pre>
=={{header|C++}}==
C++14 introduced the apostrophe (') as a numeric separator. The specification is [http://open-std.org/jtc1/sc22/wg21/docs/papers/2013/n3781.pdf n3781]. The code below will thus run only on a C++14 or later compiler :
<syntaxhighlight lang="cpp">
//Aamrun, 4th October 2021
#include <iostream>
using namespace std;
int main()
{
long long int a = 30'00'000;
std::cout <<"And with the ' in C++ 14 : "<< a << endl;
return 0;
}
</syntaxhighlight>
{{out}}
<pre>
And with the ' in C++ 14 : 3000000
</pre>
=={{header|Delphi}}==
{{works with|Delphi|6.0}}
{{libheader|}}
Delphi doesn't support any alternate number separators for compiler source code input. However, Delphi does support virtually any character for thousand and decimal separators. The following code shows how to override the Windows' thousands and decimal separator conventions so it support only the US standard. This is useful when reading and writing files. If you don't do this, files written in country may be unreadable in another country. This same technique can be used to set any decimal and thousands separator you want.
<syntaxhighlight lang="Delphi">
procedure SetInternational(Flag: boolean);
{Enable/Disable International Support }
var DefaultLCID: Integer;
begin
InternationalFlag:=Flag;
DefaultLCID := GetThreadLocale;
if Flag then
begin
{This gets a "platform" warning}
{$WARNINGS OFF}
IndSystemData.DecimalSeparator := GetLocaleChar(DefaultLCID, LOCALE_SDECIMAL, '.');
IndSystemData.ThousandSeparator := GetLocaleChar(DefaultLCID, LOCALE_STHOUSAND, ',');
{$WARNINGS ON}
end
else
begin
IndSystemData.DecimalSeparator:='.';
{No thousands separator so we can parse comma separated data}
IndSystemData.ThousandSeparator:=#0;
end;
end;
</syntaxhighlight>
{{out}}
<pre>
</pre>
=={{header|Factor}}==
Factor allows the comma <code>,</code> as a separator character in number literals.
<
12,345 . ! 12345
Line 49 ⟶ 198:
! and complex numbers
C{ 5.225,312 2.0 } . ! C{ 5.225312 2.0 }</
If one desires to define a syntax for different separator rules, that is possible:
<
<< SYNTAX: PN: scan-token "_" without string>number suffix! ; >>
Line 59 ⟶ 208:
PN: _1_2_3_ . ! 123
PN: 1__234___567 . ! 1234567
PN: 0b0___10.100001p3 . ! 20.125</
Since Factor's parser is exposed, one could even make changes to the number parser, obviating the need for parsing words.
<
<<
Line 79 ⟶ 228:
>>
3_333_333 . ! 3333333</
<!-- == Free Pascal == -->
{{omit from|Free Pascal}}
=={{header|FreeBASIC}}==
FreeBASIC does not have numeric separator syntax.
Not allow the use of the underscore _ as a digit separator.
However, you could, for example, define a macro to remove underscores.
<syntaxhighlight lang="freebasic">Function Remove(Byval Text As String, Char As String="_") As String
Dim As Long i
For n As Long = 0 To Len(Text)-1
If Text[n] <> Asc(char) Then Text[i] = Text[n]: i += 1
Next n
Return Left(Text,i)
End Function
#macro __(t,b...)
Vallng(Remove(#t,b))
#endmacro
Print __(1_234_567)
Print __(&h__D__E__A__D__B__E__E__F)
Print __(&hFF_BB_00_00 Or &h_FFBB_0000)
Print __(&b_0101_0001_1110_0000)
Print __(26-10-48,"-") 'not a dash
Print Hex(__(&hFF_BB_00_01) Or __(&h_FFBB_0010))</syntaxhighlight>
{{out}}
<pre> 1234567
3735928559
4290445312
20960
261048
FFBB0011</pre>
=={{header|Go}}==
From version 1.13
<syntaxhighlight lang="go">package main
import "fmt"
func main() {
integers := []int{1_2_3, 0b1_0_1_0_1, 0xa_bc_d, 0o4_37, 0_43_7, 0x_beef}
for _, integer := range integers {
fmt.Printf("%d ", integer)
}
floats := []float64{1_2_3_4.2_5, 6.0_22e4, 0x_1.5p-2}
for _, float := range floats {
fmt.Printf("%g ", float)
}
fmt.Println()
// none of these compile
// floats2 := []float64{_1234.25, 1234_.25, 1234._25, 1234.25_, 12__23.25}
}</syntaxhighlight>
{{out}}
<pre>
123 21 43981 287 287 48879 1234.25 60220 0.328125
</pre>
=={{header|Java}}==
Underscores have to be located within digits. The number of underscores and their position is not restricted.
<syntaxhighlight lang="java">
public class NumericSeparatorSyntax {
public static void main(String[] args) {
runTask("Underscore allowed as seperator", 1_000);
runTask("Multiple consecutive underscores allowed:", 1__0_0_0);
runTask("Many multiple consecutive underscores allowed:", 1________________________00);
runTask("Underscores allowed in multiple positions", 1__4__4);
runTask("Underscores allowed in negative number", -1__4__4);
runTask("Underscores allowed in floating point number", 1__4__4e-5);
runTask("Underscores allowed in floating point exponent", 1__4__440000e-1_2);
//runTask(_100); does not compile - cannot be before first digit
//runTask(100_); does not compile - cannot be after last digit
//runTask(144_.25); does not compile - must be within digits
//runTask(144._25); does not compile - must be within digits
}
private static void runTask(String description, long n) {
runTask(description, n, "%d");
}
private static void runTask(String description, double n) {
runTask(description, n, "%3.7f");
}
private static void runTask(String description, Number n, String format) {
System.out.printf("%s: " + format + "%n", description, n);
}
}
</syntaxhighlight>
{{out}}
<pre>
Underscore allowed as seperator: 1000
Multiple consecutive underscores allowed:: 1000
Many multiple consecutive underscores allowed:: 100
Underscores allowed in multiple positions: 144
Underscores allowed in negative number: -144
Underscores allowed in floating point number: 0.0014400
Underscores allowed in floating point exponent: 0.0000144
</pre>
=={{header|jq}}==
'''Works with jq and gojq, the C and Go implementations of jq'''
jq does not support any separator syntax for numbers, and does not provide any built-in
filters for formatting them with a thousands-separator, or for "decommatizing" strings
that could be interpreted as numbers.
The following definitions, however, can be used to commatize integers, whether
expressed as strings or as (JSON) numbers. Exponential notation is
supported, as illustrated by some of the examples below.
Note that since both gojq and sufficiently recent versions of jq support indefinitely large
numeric integers, some of the examples assume such support.
<syntaxhighlight lang=jq>
# The def of _nwise/1 can be omitted if using the C implementation of jq.
def _nwise($n):
def n: if length <= $n then . else .[0:$n] , (.[$n:] | n) end;
n;
# commatize/0 and commatize/1 are intended for integers or integer-valued strings,
# where integers of the form [-]?[0-9]*[Ee][+]?[0-9]+ are allowed.
# Notice that a leading '+' is disallowed, as is an exponent of the form '-0'.
# Output: a string
def commatize($comma):
def c: [explode | reverse | _nwise(3) | reverse | implode] | reverse | join($comma);
def e: "unable to commatize: " + tostring | error;
if type == "string"
then if test("^[0-9]+$") then c
elif test("^-[0-9]+$") then "-" + .[1:] | c
else (capture("(?<s>[-])?(?<i>[0-9]*)[Ee][+]?(?<e>[0-9]+)$") // null)
| if .
then if .i == "" then .i="1" else . end
| .s |= (if . = null then "" else . end)
| .s + ((.i + (.e|tonumber) * "0") | c)
else e
end
end
elif type == "number" and . == floor
then if . >= 0
then tostring|commatize($comma)
else "-" + (-. | tostring | commatize($comma) )
end
else e
end;
def commatize:
commatize(",");
</syntaxhighlight>
'''Examples'''
<syntaxhighlight lang=jq>
[ 1e6, 1e9, 123456789, -123456789012, 1e20, "e20", -10e19, 123456789123456789123456789 ] as $nums
| [",", ".", " ", "*"] as $seps
| range(0;$nums|length) as $i
| $nums[$i] | commatize($seps[$i] // ",")
</syntaxhighlight>
{{output}}
<pre>
1,000,000
1.000.000.000
123 456 789
-123*456*789*012
100,000,000,000,000,000,000
100,000,000,000,000,000,000
-100,000,000,000,000,000,000
123,456,789,123,456,789,123,456,789
</pre>
=={{header|Julia}}==
Line 91 ⟶ 412:
Commas are not allowed in numeric literals.
<
julia> 2_9
29
Line 123 ⟶ 444:
julia> 10__000__000
ERROR: UndefVarError: __000__000 not defined
</syntaxhighlight>
=={{header|
Nim allows to use underscores <code>_</code> in numeric literals. An underscore must be preceded and followed by a digit, which means that it cannot be placed at start or end of a literal and that consecutive underscores are forbidden.
Using Julia examples, for instance in "inim" REPL:
<syntaxhighlight lang="nim">
const a = 2_9 # 29
const b = 2_9_9_0 # 2990
const c = 2_9_9.0_01 # 299.001
const d = 1._01 # Error: invalid token: _ (\95)
const e = -1_0 # -10
const f = -_10 # Error: invalid token: _ (\95)
const g = 0x34_ff # 0x34ff
const h = 0x_34ff # Error: invalid number: '0x_34ff'
const i = 10_000_000 # 10000000
const j = 10__000__000 # Error: only single underscores may occur in a token and token may not end with an underscore: e.g. '1__1' and '1_' are invalid
</syntaxhighlight>
=={{header|OCaml}}==
Underscores can be used as separators in integer or floating-point literals, and they are ignored. Underscores can be in any position except at the beginning, and you can use consecutive underscores.
<syntaxhighlight lang="ocaml">Printf.printf "%d\n" 1_2_3;; (* 123 *)
Printf.printf "%d\n" 0b1_0_1_0_1;; (* 21 *)
Printf.printf "%d\n" 0xa_bc_d;; (* 43981 *)
Printf.printf "%d\n" 12__34;; (* 1234 *)
Printf.printf "%f\n" 1_2_3_4.2_5;; (* 1234.250000 *)
Printf.printf "%f\n" 6.0_22e4;; (* 60220.000000 *)
Printf.printf "%f\n" 1234_.25;; (* 1234.250000 *)
Printf.printf "%f\n" 1234._25;; (* 1234.250000 *)
Printf.printf "%f\n" 1234.25_;; (* 1234.250000 *)</syntaxhighlight>
=={{header|Pascal}}==
Works with FPC (currently only version 3.3.1).
An underscore can be used as a digit separator. This is by default in {$mode delphi}, in other modes it is activated using the {$modeswitch underscoreisseparator}.
<syntaxhighlight lang="pascal">
program test;
{$mode fpc}
{$modeswitch underscoreisseparator}
begin
WriteLn(%1001_1001);
WriteLn(&121_102);
WriteLn(-1_123_123);
WriteLn($1_123_123);
WriteLn(-1_123___123.000_000);
WriteLn(1_123_123.000_000e1_2);
end.
</syntaxhighlight>
=={{header|Perl}}==
Perl allows underscore as a grouping / separator character in numeric inputs, as long as you use it between digits, and you do not use two underscores in a row:
<syntaxhighlight lang="perl"># Int
print 1_2_3, "\n"; # 123
# Binary Int
# Hexadecimal Int
# Rat
# Num
=={{header|Phix}}==
Phix simply ignores underscores in numeric literals, however a leading underscore signifies a normal identifier, much like a123 or tmp2.<br>
Commas are not allowed in numeric literals, since they delimit sequence elements, routine parameters, and such like, for example {1,2,3,4}.
<!--<syntaxhighlight lang="phix">(phixonline)-->
<span style="color: #008080;">with</span> <span style="color: #008080;">javascript_semantics</span>
<span style="color: #0000FF;">?</span> <span style="color: #000000;">1_2_3</span> <span style="color: #000080;font-style:italic;">-- 123
--? _1234.25 -- undefined identifier _1234</span>
<span style="color: #0000FF;">?</span> <span style="color: #000000;">0b1_0_1_0_1</span> <span style="color: #000080;font-style:italic;">-- 21</span>
<span style="color: #0000FF;">?</span> <span style="color: #000000;">0b_1_0_1_0_1</span> <span style="color: #000080;font-style:italic;">-- 21</span>
<span style="color: #0000FF;">?</span> <span style="color: #000000;">0xa_bc_d</span> <span style="color: #000080;font-style:italic;">-- 43981</span>
<span style="color: #0000FF;">?</span> <span style="color: #000000;">#_DEAD_BEEF_</span> <span style="color: #000080;font-style:italic;">-- 3735928559.0</span>
<span style="color: #0000FF;">?</span> <span style="color: #000000;">0x_dead_beef</span> <span style="color: #000080;font-style:italic;">-- 3735928559.0</span>
<span style="color: #0000FF;">?</span> <span style="color: #000000;">3.14_15_93</span> <span style="color: #000080;font-style:italic;">-- 3.141593</span>
<span style="color: #0000FF;">?</span> <span style="color: #000000;">1_2_3_4.2_5</span> <span style="color: #000080;font-style:italic;">-- 1234.25</span>
<span style="color: #0000FF;">?</span> <span style="color: #000000;">1234_.25</span> <span style="color: #000080;font-style:italic;">-- 1234.25</span>
<span style="color: #0000FF;">?</span> <span style="color: #000000;">1234._25</span> <span style="color: #000080;font-style:italic;">-- 1234.25</span>
<span style="color: #0000FF;">?</span> <span style="color: #000000;">1234.25_</span> <span style="color: #000080;font-style:italic;">-- 1234.25</span>
<span style="color: #0000FF;">?</span> <span style="color: #000000;">12__34.25</span> <span style="color: #000080;font-style:italic;">-- 1234.25</span>
<span style="color: #0000FF;">?</span> <span style="color: #000000;">6.0_22e4</span> <span style="color: #000080;font-style:italic;">-- 60220</span>
<!--</syntaxhighlight>-->
=={{header|Python}}==
{{works with|Python|3.6+}}
The Syntax for separators in numbers, (numeric literals), is given [https://docs.python.org/3/reference/lexical_analysis.html#integer-literals here] in the Python documentation.
Line 165 ⟶ 543:
* E.g. 100_000_000_000, 0x_dead_beef, 3.14_15_93
=={{header|Quackery}}==
Quackery does not have numeric separator syntax. However, as the compiler is extensible one could, for example, define a builder (i.e. a compiler directive) <code>n</code> to strip commas from the space delimited number following it in the Quackscript.
<syntaxhighlight lang="quackery"> [ nextword
[] swap witheach
[ dup char , = iff
drop else join ]
swap join ] builds n ( [ $ --> $ [ )</syntaxhighlight>
{{out}}
Testing in the Quackery shell.
<pre>/O> [ nextword
... [] swap witheach
... [ dup char , = iff
... drop else join ]
... swap join ] builds n ( [ $ --> [ $ )
...
Stack empty.
/O> n 123,456,789
...
Stack: 123456789
/O></pre>
=={{header|Racket}}==
Line 170 ⟶ 579:
Vanilla Racket does not have numeric separator syntax. However, it can be defined by users. A quick solution is to use <code>#%top</code>:
<
(require syntax/parse/define
Line 185 ⟶ 594:
1_234_567.89
1_234__567.89</
{{out}}
Line 199 ⟶ 608:
If we wish to, for example, disallow multiple consecutive separators like <code>1_234__567.89</code>, we could do so easily:
<
(require syntax/parse/define
Line 216 ⟶ 625:
1_234_567.89
1_234__567.89</
{{out}}
Line 224 ⟶ 633:
A more complicated solution is to create a new language that changes Racket's reader. One approach is to adjust the readtable to recognize the new number literals so that we don't need to change the whole reader. While being slightly more complicated, this solution is better in a sense that <code>(read)</code> will also recognize the new number literals.
=={{header|Raku}}==
(formerly Perl 6)
Raku allows underscore as a grouping / separator character in numeric inputs, though there are a few restrictions.
<syntaxhighlight lang="raku" line># Any numeric input value may use an underscore as a grouping/separator character.
# May occur in nearly any position, in any* number. * See restrictions below.
# Int
say 1_2_3; # 123
# Binary Int
say 0b1_0_1_0_1; # 21
# Hexadecimal Int
say 0xa_bc_d; # 43981
# Rat
say 1_2_3_4.2_5; # 1234.25
# Num
say 6.0_22e4; # 60220
# There are some restrictions on the placement.
# An underscore may not be on an edge boundary, or next to another underscore.
# The following are all syntax errors.
# say _1234.25;
# say 1234_.25;
# say 1234._25;
# say 1234.25_;
# say 12__34.25;</syntaxhighlight>
=={{header|REXX}}==
The REXX language doesn't allow commas (or other separators) in decimal numbers (for input), commas are considered argument separators (if used from within a program, or as (passed/invoked) arguments from any program).
However, for '''binary''' and '''hexadecimal''' numbers, (multiple) blanks are allowed in appropriate places.
Line 254 ⟶ 695:
+ 4500
- 1719
There is a way to work around such that blanks or commas could be used within a REXX program with a bit of coding:
<syntaxhighlight lang="rexx">pi= 3 . 14159 26535 89793 23846 26433 83279 50288 41971 69399 37510 58209 74945
pi= 3 . 14159_26535_89793_23846_26433_83279_50288_41971_69399_37510_58209_74945
pi = space( translate(pi, , ",_"), 0)</syntaxhighlight>
─── where the last REXX statement will translate (change) any number of separator characters into blanks, and
<br>remove all blanks from the "number".
=={{header|Ruby}}==
Ruby supports one separator, the underscore. It behaves like Perl's underscore.
=={{header|Scala}}==
Line 259 ⟶ 712:
''"The digits of a numeric literal may be separated by arbitrarily many underscores for purposes of legibility."''
Let's see how its work in a Scala REPL session:
<
Type in expressions for evaluation. Or try :help.
Line 284 ⟶ 737:
res5: Double = 1234.25
scala></
=={{header|Sidef}}==
Sidef allows underscores as a separator character in numeric inputs.
<
say 1_2_3; # 123
Line 309 ⟶ 762:
say 1234.25_; # 1234.25
say 12__34.25; # 1234.25
# say _1234.25; # syntax error</
=={{header|V (Vlang)}}==
Vlang also supports writing numbers with _ as a separator.
<syntaxhighlight lang="Rust">
fn main() {
numbers := [1_000_000, 2_882, 3_122, 0b1_0_0_0_1, 0xa_bc_d]
for number in numbers {println(number)}
}
</syntaxhighlight>
{{out}}
<pre>
1000000
2882
3122
17
43981
</pre>
=={{header|XPL0}}==
Numbers can contain underlines, which is useful for making long strings
of digits easier to recognize. Underlines in coded constants are simply
ignored by the parser. Underlines in numbers typed in to a running
program are also ignored.
<syntaxhighlight lang="xpl0">def Meg = 1_000_000;
[IntOut(0, Meg); CrLf(0);
RlOut(0, 123__45.67_89_); CrLf(0);
HexOut(0, $ABCD_EF01); CrLf(0);
HexOut(0, %1010_1011_1100_1101_1110_1111_0000_0001); CrLf(0);
IntOut(0, IntIn(0));
]</syntaxhighlight>
{{out}}
<pre>
1000000
12345.67890
ABCDEF01
ABCDEF01
-321_00__0_
-321000
</pre>
=={{header|Wren}}==
{{libheader|Wren-fmt}}
Consistent with its C heritage, Wren doesn't support any form of separator in numeric literals.
However, it's possible using the Wren-fmt module to add any single character 'thousands' separator when 'stringifying' an integer as the example below shows.
As currently written, this just supports separation of decimal integers into 3 digit groups from the right though it could be extended to deal with other scenarios as well.
<syntaxhighlight lang="wren">import "./fmt" for Fmt
var nums = [1e6, 1e9, 123456789, -123456789012]
var seps = [",", ".", " ", "*"]
for (i in 0...nums.count) System.print(Fmt.commatize(nums[i], seps[i]))</syntaxhighlight>
{{out}}
<pre>
1,000,000
1.000.000.000
123 456 789
-123*456*789*012
</pre>
=={{header|zkl}}==
<syntaxhighlight lang="zkl">For source code, integers and floats allow a "_" between digits (or trailing)
and completely ignores them:
1_000 == 1_000_ == 1_0_0_0 == 1__________000
1_2.3_4 == 12.34
For hex, both "_" and "|" are allowed: 0x12|34</syntaxhighlight>
<syntaxhighlight lang="zkl">For printing, the String.fmt method will add separators for %d (interger: ","),
%f (float: ","), %x (hex: "|") and %2B (binary: "|").
"%,d %,.0f %,x %,.2B".fmt(1234, 1234.0, 0x1234, 0x1234).println();
--> "1,234 1,234 12|34 1|0010|0011|0100"
Each objects toString method has optional parameters to specify a separator
and "column width". This method is called (by fmt) for the above tags.</syntaxhighlight>
| |||