Closures/Value capture: Difference between revisions

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=={{header|11l}}==
=={{header|11l}}==
<lang 11l>[(() -> Int)] funcs
<syntaxhighlight lang="11l">[(() -> Int)] funcs
L(i) 10
L(i) 10
funcs.append(() -> @=i * @=i)
funcs.append(() -> @=i * @=i)
print(funcs[3]())</lang>
print(funcs[3]())</syntaxhighlight>


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One way to realize closures in Ada is the usage of protected objects.
One way to realize closures in Ada is the usage of protected objects.


<lang Ada>with Ada.Text_IO;
<syntaxhighlight lang="Ada">with Ada.Text_IO;


procedure Value_Capture is
procedure Value_Capture is
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Ada.Text_IO.Put(Integer'Image(A(I).Result));
Ada.Text_IO.Put(Integer'Image(A(I).Result));
end loop;
end loop;
end Value_Capture;</lang>
end Value_Capture;</syntaxhighlight>


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{{works with|ALGOL 68G|2.8}}
{{works with|ALGOL 68G|2.8}}


<lang algol68>
<syntaxhighlight lang="algol68">
[1:10]PROC(BOOL)INT squares;
[1:10]PROC(BOOL)INT squares;


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FOR i FROM 1 TO 10 DO print(squares[i](FALSE)) OD
FOR i FROM 1 TO 10 DO print(squares[i](FALSE)) OD


</syntaxhighlight>
</lang>
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<pre>
<pre>
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=={{header|AntLang}}==
=={{header|AntLang}}==
<lang AntLang>fns: {n: x; {n expt 2}} map range[10]
<syntaxhighlight lang="AntLang">fns: {n: x; {n expt 2}} map range[10]
(8 elem fns)[]</lang>
(8 elem fns)[]</syntaxhighlight>


=={{header|AppleScript}}==
=={{header|AppleScript}}==
{{trans|JavaScript}}
{{trans|JavaScript}}
<lang AppleScript>on run
<syntaxhighlight lang="AppleScript">on run
set fns to {}
set fns to {}
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end |λ|
end |λ|
end script
end script
end closure</lang>
end closure</syntaxhighlight>
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<pre>9</pre>
<pre>9</pre>
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Or, in a more functional pattern of composition:
Or, in a more functional pattern of composition:


<lang AppleScript>-- CLOSURE --------------------------------------------------------------------
<syntaxhighlight lang="AppleScript">-- CLOSURE --------------------------------------------------------------------


script closure
script closure
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end script
end script
end if
end if
end mReturn</lang>
end mReturn</syntaxhighlight>
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<pre>9</pre>
<pre>9</pre>
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=={{header|Axiom}}==
=={{header|Axiom}}==
Using the Spad compiler:
Using the Spad compiler:
<lang Axiom>)abbrev package TESTP TestPackage
<syntaxhighlight lang="Axiom">)abbrev package TESTP TestPackage
TestPackage() : with
TestPackage() : with
test: () -> List((()->Integer))
test: () -> List((()->Integer))
== add
== add
test() == [(() +-> i^2) for i in 1..10]</lang>
test() == [(() +-> i^2) for i in 1..10]</syntaxhighlight>


This can be called from the interpreter using:
This can be called from the interpreter using:
<lang Axiom>[x() for x in test()]</lang>
<syntaxhighlight lang="Axiom">[x() for x in test()]</syntaxhighlight>


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<lang Axiom>[1,4,9,16,25,36,49,64,81,100]
<syntaxhighlight lang="Axiom">[1,4,9,16,25,36,49,64,81,100]
Type: List(Integer)</lang>
Type: List(Integer)</syntaxhighlight>


=={{header|Babel}}==
=={{header|Babel}}==


<lang babel>((main {
<syntaxhighlight lang="babel">((main {
{ iter
{ iter
1 take bons 1 take
1 take bons 1 take
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10 times
10 times
collect !
collect !
{eval %d nl <<} each }))</lang>
{eval %d nl <<} each }))</syntaxhighlight>


{{out}}
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<lang babel>100
<syntaxhighlight lang="babel">100
81
81
64
64
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9
9
4
4
1</lang>
1</syntaxhighlight>


Essentially, a function has been constructed for each value to be squared (10 down to 1). The cp operator ensures that we generate a fresh copy of the number to be squared, as well as the code for multiplying, {*}.
Essentially, a function has been constructed for each value to be squared (10 down to 1). The cp operator ensures that we generate a fresh copy of the number to be squared, as well as the code for multiplying, {*}.
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=={{header|Bracmat}}==
=={{header|Bracmat}}==
<lang bracmat>( -1:?i
<syntaxhighlight lang="bracmat">( -1:?i
& :?funcs
& :?funcs
& whl
& whl
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& whl'(!funcs:%?func %?funcs&out$(!func$))
& whl'(!funcs:%?func %?funcs&out$(!func$))
);
);
</syntaxhighlight>
</lang>
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<pre>0
<pre>0
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Non-portable. Copying a function body depends on implementation-specific semantics of volatile, if the replacement target still exists after optimization, if the dest memory is suitably aligned, if the memory is executable, if it makes any function calls to a relative offset, if it refers to any memory location with an absolute address, etc. It only very occasionally works.
Non-portable. Copying a function body depends on implementation-specific semantics of volatile, if the replacement target still exists after optimization, if the dest memory is suitably aligned, if the memory is executable, if it makes any function calls to a relative offset, if it refers to any memory location with an absolute address, etc. It only very occasionally works.


<lang c>#include <stdio.h>
<syntaxhighlight lang="c">#include <stdio.h>
#include <string.h>
#include <string.h>
#include <stdlib.h>
#include <stdlib.h>
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return 0;
return 0;
}</lang>
}</syntaxhighlight>
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<lang>func[0]: 0
<syntaxhighlight lang="text">func[0]: 0
func[1]: 1
func[1]: 1
func[2]: 4
func[2]: 4
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func[6]: 36
func[6]: 36
func[7]: 49
func[7]: 49
func[8]: 64</lang>
func[8]: 64</syntaxhighlight>


===Greenspunned mini Lisp dialect===
===Greenspunned mini Lisp dialect===
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See [[Closures/Variable_capture/C]] for complete code. The relevant excerpt is:
See [[Closures/Variable_capture/C]] for complete code. The relevant excerpt is:


<lang c>void init(void)
<syntaxhighlight lang="c">void init(void)
{
{
t = intern(lit("t"));
t = intern(lit("t"));
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}
}
return 0;
return 0;
}</lang>
}</syntaxhighlight>


Here, we create an environment explicitly as an association list
Here, we create an environment explicitly as an association list
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=={{header|C sharp|C#}}==
=={{header|C sharp|C#}}==
===Using Linq===
===Using Linq===
<lang csharp>using System;
<syntaxhighlight lang="csharp">using System;
using System.Linq;
using System.Linq;


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}
}
}
}
}</lang>
}</syntaxhighlight>
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<lang>0
<syntaxhighlight lang="text">0
1
1
4
4
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36
36
49
49
64</lang>
64</syntaxhighlight>


===Using delegates only===
===Using delegates only===


<lang csharp>
<syntaxhighlight lang="csharp">
using System;
using System;
using System.Collections.Generic;
using System.Collections.Generic;
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}
}
}
}
</syntaxhighlight>
</lang>
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<lang>0
<syntaxhighlight lang="text">0
1
1
4
4
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36
36
49
49
64</lang>
64</syntaxhighlight>


=={{header|C++}}==
=={{header|C++}}==
{{works with|C++11}}
{{works with|C++11}}
<lang cpp>#include <iostream>
<syntaxhighlight lang="cpp">#include <iostream>
#include <functional>
#include <functional>
#include <vector>
#include <vector>
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std::cout << f( ) << std::endl ;
std::cout << f( ) << std::endl ;
return 0;
return 0;
}</lang>
}</syntaxhighlight>
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<pre>0
<pre>0
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=={{header|Ceylon}}==
=={{header|Ceylon}}==
<lang ceylon>shared void run() {
<syntaxhighlight lang="ceylon">shared void run() {
//create a list of closures with a list comprehension
//create a list of closures with a list comprehension
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print("closure number ``i`` returns: ``closure()``");
print("closure number ``i`` returns: ``closure()``");
}
}
}</lang>
}</syntaxhighlight>


=={{header|Clojure}}==
=={{header|Clojure}}==
<lang clojure>(def funcs (map #(fn [] (* % %)) (range 11)))
<syntaxhighlight lang="clojure">(def funcs (map #(fn [] (* % %)) (range 11)))
(printf "%d\n%d\n" ((nth funcs 3)) ((nth funcs 4)))</lang>
(printf "%d\n%d\n" ((nth funcs 3)) ((nth funcs 4)))</syntaxhighlight>
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<pre>9
<pre>9
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=={{header|CoffeeScript}}==
=={{header|CoffeeScript}}==


<lang coffeescript>
<syntaxhighlight lang="coffeescript">
# Generate an array of functions.
# Generate an array of functions.
funcs = ( for i in [ 0...10 ] then do ( i ) -> -> i * i )
funcs = ( for i in [ 0...10 ] then do ( i ) -> -> i * i )
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# Call each function to demonstrate value capture.
# Call each function to demonstrate value capture.
console.log func() for func in funcs
console.log func() for func in funcs
</syntaxhighlight>
</lang>


=={{header|Common Lisp}}==
=={{header|Common Lisp}}==
<lang lisp>CL-USER> (defparameter alist
<syntaxhighlight lang="lisp">CL-USER> (defparameter alist
(loop for i from 1 to 10
(loop for i from 1 to 10
collect (cons i (let ((i i))
collect (cons i (let ((i i))
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4
4
CL-USER> (funcall (cdr (assoc 8 alist)))
CL-USER> (funcall (cdr (assoc 8 alist)))
64</lang>
64</syntaxhighlight>


The ''loop'' mutates its binding ''i''. The purpose of <code>(let ((i i)) ...)</code> is to create a different binding ''i'' for each ''lambda'' to capture. Otherwise, all 10 lambdas would capture the same binding and return 100.
The ''loop'' mutates its binding ''i''. The purpose of <code>(let ((i i)) ...)</code> is to create a different binding ''i'' for each ''lambda'' to capture. Otherwise, all 10 lambdas would capture the same binding and return 100.
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=={{header|D}}==
=={{header|D}}==
===Less Functional Version===
===Less Functional Version===
<lang d>import std.stdio;
<syntaxhighlight lang="d">import std.stdio;


void main() {
void main() {
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writeln(funcs[3]());
writeln(funcs[3]());
}</lang>
}</syntaxhighlight>
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<pre>9</pre>
<pre>9</pre>
===More Functional Version===
===More Functional Version===
<lang d>void main() {
<syntaxhighlight lang="d">void main() {
import std.stdio, std.range, std.algorithm;
import std.stdio, std.range, std.algorithm;


10.iota.map!(i => () => i ^^ 2).map!q{ a() }.writeln;
10.iota.map!(i => () => i ^^ 2).map!q{ a() }.writeln;
}</lang>
}</syntaxhighlight>
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<pre>[0, 1, 4, 9, 16, 25, 36, 49, 64, 81]</pre>
<pre>[0, 1, 4, 9, 16, 25, 36, 49, 64, 81]</pre>
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=={{header|Delphi}}==
=={{header|Delphi}}==
{{works with|Delphi 2009}}
{{works with|Delphi 2009}}
<lang Delphi>program Project1;
<syntaxhighlight lang="Delphi">program Project1;


type
type
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for i := Low(Funcs) to High(Funcs) do
for i := Low(Funcs) to High(Funcs) do
Writeln(Funcs[i]());
Writeln(Funcs[i]());
end.</lang>
end.</syntaxhighlight>
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<pre>0
<pre>0
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Dyalect captures variables by reference, therefore a way to achieve this is to capture a variable through a closure which in its turn returns a anonymous function like so:
Dyalect captures variables by reference, therefore a way to achieve this is to capture a variable through a closure which in its turn returns a anonymous function like so:


<lang dyalect>var xs = []
<syntaxhighlight lang="dyalect">var xs = []
let num = 10
let num = 10


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for x in xs {
for x in xs {
print(x())
print(x())
}</lang>
}</syntaxhighlight>


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=={{header|EchoLisp}}==
=={{header|EchoLisp}}==
<lang scheme>
<syntaxhighlight lang="scheme">
(define (fgen i) (lambda () (* i i)))
(define (fgen i) (lambda () (* i i)))
(define fs (for/vector ((i 10)) (fgen i))) ;; vector of 10 anonymous functions
(define fs (for/vector ((i 10)) (fgen i))) ;; vector of 10 anonymous functions
((vector-ref fs 5)) ;; calls fs[5]
((vector-ref fs 5)) ;; calls fs[5]
→ 25
→ 25
</syntaxhighlight>
</lang>


=={{header|Elena}}==
=={{header|Elena}}==
ELENA 4.1 :
ELENA 4.1 :
<lang elena>import system'routines;
<syntaxhighlight lang="elena">import system'routines;
import extensions;
import extensions;
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functions.forEach:(func) { console.printLine(func()) }
functions.forEach:(func) { console.printLine(func()) }
}</lang>
}</syntaxhighlight>
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<pre>0
<pre>0
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=={{header|Elixir}}==
=={{header|Elixir}}==
<lang elixir>funs = for i <- 0..9, do: (fn -> i*i end)
<syntaxhighlight lang="elixir">funs = for i <- 0..9, do: (fn -> i*i end)
Enum.each(funs, &IO.puts &1.())</lang>
Enum.each(funs, &IO.puts &1.())</syntaxhighlight>


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As of Emacs 24.3, lexical closures are supported, therefore alleviating hacks such as lexical-let.
As of Emacs 24.3, lexical closures are supported, therefore alleviating hacks such as lexical-let.


<lang lisp>;; -*- lexical-binding: t; -*-
<syntaxhighlight lang="lisp">;; -*- lexical-binding: t; -*-
(mapcar #'funcall
(mapcar #'funcall
(mapcar (lambda (x)
(mapcar (lambda (x)
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(* x x)))
(* x x)))
'(1 2 3 4 5 6 7 8 9 10)))
'(1 2 3 4 5 6 7 8 9 10)))
;; => (1 4 9 16 25 36 49 64 81 100)</lang>
;; => (1 4 9 16 25 36 49 64 81 100)</syntaxhighlight>


=={{header|Erlang}}==
=={{header|Erlang}}==
Erlang uses lexical scoping and has anonymous functions.
Erlang uses lexical scoping and has anonymous functions.
<lang erlang>
<syntaxhighlight lang="erlang">
-module(capture_demo).
-module(capture_demo).
-export([demo/0]).
-export([demo/0]).
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io:fwrite("~B~n",[F()])
io:fwrite("~B~n",[F()])
end, Funs).
end, Funs).
</syntaxhighlight>
</lang>
<pre>
<pre>
1> capture_demo:demo().
1> capture_demo:demo().
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=={{header|F_Sharp|F#}}==
=={{header|F_Sharp|F#}}==
Nearly identical to OCaml
Nearly identical to OCaml
<lang fsharp>[<EntryPoint>]
<syntaxhighlight lang="fsharp">[<EntryPoint>]
let main argv =
let main argv =
let fs = List.init 10 (fun i -> fun () -> i*i)
let fs = List.init 10 (fun i -> fun () -> i*i)
do List.iter (fun f -> printfn "%d" <| f()) fs
do List.iter (fun f -> printfn "%d" <| f()) fs
0</lang>
0</syntaxhighlight>


With List.map
With List.map
<lang fsharp>[<EntryPoint>]
<syntaxhighlight lang="fsharp">[<EntryPoint>]
let main argv =
let main argv =
let fs = List.map (fun i -> fun () -> i*i) [0..9]
let fs = List.map (fun i -> fun () -> i*i) [0..9]
do List.iter (fun f -> printfn "%d" <| f()) fs
do List.iter (fun f -> printfn "%d" <| f()) fs
0</lang>
0</syntaxhighlight>


With List.mapi
With List.mapi
<lang fsharp>[<EntryPoint>]
<syntaxhighlight lang="fsharp">[<EntryPoint>]
let main argv =
let main argv =
let fs = List.mapi (fun i x -> fun () -> i*i) (List.replicate 10 None)
let fs = List.mapi (fun i x -> fun () -> i*i) (List.replicate 10 None)
do List.iter (fun f -> printfn "%d" <| f()) fs
do List.iter (fun f -> printfn "%d" <| f()) fs
0</lang>
0</syntaxhighlight>


With an infinite sequence
With an infinite sequence
<lang fsharp>[<EntryPoint>]
<syntaxhighlight lang="fsharp">[<EntryPoint>]
let main argv =
let main argv =
let fs = Seq.initInfinite (fun i -> fun () -> i*i)
let fs = Seq.initInfinite (fun i -> fun () -> i*i)
do Seq.iter (fun f -> printfn "%d" <| f()) (Seq.take 10 fs)
do Seq.iter (fun f -> printfn "%d" <| f()) (Seq.take 10 fs)
0</lang>
0</syntaxhighlight>


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=={{header|Factor}}==
=={{header|Factor}}==
===Using lexical variables===
===Using lexical variables===
<lang factor>USING: io kernel locals math prettyprint sequences ;
<syntaxhighlight lang="factor">USING: io kernel locals math prettyprint sequences ;


[let
[let
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seq nth call .
seq nth call .
] each
] each
]</lang>
]</syntaxhighlight>


<pre>$ ./factor script.factor
<pre>$ ./factor script.factor
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Forget the variable! Each ''fried quotation'' captures some values by pulling them from the stack.
Forget the variable! Each ''fried quotation'' captures some values by pulling them from the stack.


<lang factor>USING: fry io kernel math prettyprint sequences ;
<syntaxhighlight lang="factor">USING: fry io kernel math prettyprint sequences ;


! Push a sequence of 10 quotations
! Push a sequence of 10 quotations
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over nth call .
over nth call .
] each
] each
drop</lang>
drop</syntaxhighlight>


=={{header|Fantom}}==
=={{header|Fantom}}==


<lang fantom>
<syntaxhighlight lang="fantom">
class Closures
class Closures
{
{
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}
}
}
}
</syntaxhighlight>
</lang>


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=={{header|Forth}}==
=={{header|Forth}}==
<lang forth>: xt-array here { a }
<syntaxhighlight lang="forth">: xt-array here { a }
10 cells allot 10 0 do
10 cells allot 10 0 do
:noname i ]] literal dup * ; [[ a i cells + !
:noname i ]] literal dup * ; [[ a i cells + !
loop a ;
loop a ;


xt-array 5 cells + @ execute .</lang>
xt-array 5 cells + @ execute .</syntaxhighlight>


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<lang forth>25</lang>
<syntaxhighlight lang="forth">25</syntaxhighlight>


=={{header|FreeBASIC}}==
=={{header|FreeBASIC}}==
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FreeBASIC doesn't support closures or anonymous methods, as such. However, what we can do is to create an array of objects to capture their index and then call a method on those objects which squares the index. This approach is similar to how some other object oriented languages implement closures 'under the hood'.
FreeBASIC doesn't support closures or anonymous methods, as such. However, what we can do is to create an array of objects to capture their index and then call a method on those objects which squares the index. This approach is similar to how some other object oriented languages implement closures 'under the hood'.


<lang freebasic>' FB 1.05.0 Win64
<syntaxhighlight lang="freebasic">' FB 1.05.0 Win64


Type Closure
Type Closure
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Print
Print
Print "Press any key to quit"
Print "Press any key to quit"
Sleep</lang>
Sleep</syntaxhighlight>


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=={{header|Go}}==
=={{header|Go}}==
<lang go>package main
<syntaxhighlight lang="go">package main


import "fmt"
import "fmt"
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fmt.Println("func #0:", fs[0]())
fmt.Println("func #0:", fs[0]())
fmt.Println("func #3:", fs[3]())
fmt.Println("func #3:", fs[3]())
}</lang>
}</syntaxhighlight>
{{out}}
{{out}}
<pre>
<pre>
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=={{header|Groovy}}==
=={{header|Groovy}}==
Solution:
Solution:
<lang groovy>def closures = (0..9).collect{ i -> { -> i*i } }</lang>
<syntaxhighlight lang="groovy">def closures = (0..9).collect{ i -> { -> i*i } }</syntaxhighlight>


Test:
Test:
<lang groovy>assert closures instanceof List
<syntaxhighlight lang="groovy">assert closures instanceof List
assert closures.size() == 10
assert closures.size() == 10
closures.each { assert it instanceof Closure }
closures.each { assert it instanceof Closure }
println closures[7]()</lang>
println closures[7]()</syntaxhighlight>


{{out}}
{{out}}
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Using <code>map</code>:
Using <code>map</code>:


<lang haskell>fs = map (\i _ -> i * i) [1 .. 10]</lang>
<syntaxhighlight lang="haskell">fs = map (\i _ -> i * i) [1 .. 10]</syntaxhighlight>


Using list comprehensions:
Using list comprehensions:


<lang haskell>fs = [const $ i * i | i <- [1 .. 10]]</lang>
<syntaxhighlight lang="haskell">fs = [const $ i * i | i <- [1 .. 10]]</syntaxhighlight>


Using infinite lists:
Using infinite lists:


<lang haskell>fs = take 10 coFs where coFs = [const $ i * i | i <- [1 ..]]</lang>
<syntaxhighlight lang="haskell">fs = take 10 coFs where coFs = [const $ i * i | i <- [1 ..]]</syntaxhighlight>


Testing:
Testing:


<lang haskell>> :t fs
<syntaxhighlight lang="haskell">> :t fs
fs :: [b -> Integer]
fs :: [b -> Integer]
> map ($ ()) fs
> map ($ ()) fs
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100
100
> fs !! 8 $ undefined
> fs !! 8 $ undefined
81</lang>
81</syntaxhighlight>


=={{header|Icon}} and {{header|Unicon}}==
=={{header|Icon}} and {{header|Unicon}}==
This uses Unicon specific calling sequences for co-expressions. It can be made to run under Icon by modifying the calling syntax.
This uses Unicon specific calling sequences for co-expressions. It can be made to run under Icon by modifying the calling syntax.


<lang Unicon>procedure main(args) # Closure/Variable Capture
<syntaxhighlight lang="Unicon">procedure main(args) # Closure/Variable Capture
every put(L := [], vcapture(1 to 10)) # build list of index closures
every put(L := [], vcapture(1 to 10)) # build list of index closures
write("Randomly selecting L[",i := ?*L,"] = ",L[i]()) # L[i]() calls the closure
write("Randomly selecting L[",i := ?*L,"] = ",L[i]()) # L[i]() calls the closure
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procedure makeProc(A) # the makeProc PDCO from the UniLib Utils package
procedure makeProc(A) # the makeProc PDCO from the UniLib Utils package
return (@A[1], A[1])
return (@A[1], A[1])
end</lang>
end</syntaxhighlight>


{{libheader|Unicon Code Library}}
{{libheader|Unicon Code Library}}
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=={{header|Io}}==
=={{header|Io}}==
<lang>blist := list(0,1,2,3,4,5,6,7,8,9) map(i,block(i,block(i*i)) call(i))
<syntaxhighlight lang="text">blist := list(0,1,2,3,4,5,6,7,8,9) map(i,block(i,block(i*i)) call(i))
writeln(blist at(3) call) // prints 9</lang>
writeln(blist at(3) call) // prints 9</syntaxhighlight>


=={{header|J}}==
=={{header|J}}==
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The natural way of implementing this in J is to define a function which produces a gerund of a constant function.
The natural way of implementing this in J is to define a function which produces a gerund of a constant function.


<lang j>constF=:3 :0
<syntaxhighlight lang="j">constF=:3 :0
{.''`(y "_)
{.''`(y "_)
)</lang>
)</syntaxhighlight>


Thus, a list of 10 functions each producing a value in 0..9, and another with their squares:
Thus, a list of 10 functions each producing a value in 0..9, and another with their squares:


<lang j>flist=: constF"0 i.10
<syntaxhighlight lang="j">flist=: constF"0 i.10
slist=: constF"0 *:i.10</lang>
slist=: constF"0 *:i.10</syntaxhighlight>


Referencing a function by its index (its position in that list):
Referencing a function by its index (its position in that list):


<lang j> flist @.3
<syntaxhighlight lang="j"> flist @.3
3"_
3"_
slist @.3
slist @.3
9"_</lang>
9"_</syntaxhighlight>


Using a function, given its index:
Using a function, given its index:


<lang j> flist @.4''
<syntaxhighlight lang="j"> flist @.4''
4
4
slist @.4''
slist @.4''
16</lang>
16</syntaxhighlight>


Running a randomly picked function which is not the last one:
Running a randomly picked function which is not the last one:


<lang j> flist@.(?9) ''
<syntaxhighlight lang="j"> flist@.(?9) ''
7
7
slist@.(?9) ''
slist@.(?9) ''
25</lang>
25</syntaxhighlight>


===Tacit (unorthodox) version===
===Tacit (unorthodox) version===
In J only adverbs and conjunctions (functionals) can produce verbs (functions)... Unless they are forced to cloak as verbs; in this instance, the rank conjunction (“) cloaks as a dyadic verb. (Note that this takes advantage of a bug/feature where the interpreter does not produce a result with [http://www.jsoftware.com/help/dictionary/dictb.htm the correct shape]):
In J only adverbs and conjunctions (functionals) can produce verbs (functions)... Unless they are forced to cloak as verbs; in this instance, the rank conjunction (“) cloaks as a dyadic verb. (Note that this takes advantage of a bug/feature where the interpreter does not produce a result with [http://www.jsoftware.com/help/dictionary/dictb.htm the correct shape]):


<lang j> ( VL=. (<@:((<'"')(0:`)(,^:)&_))"0@:(^&2)@:i. 10 ) NB. Producing a list of boxed anonymous verbs (functions)
<syntaxhighlight lang="j"> ( VL=. (<@:((<'"')(0:`)(,^:)&_))"0@:(^&2)@:i. 10 ) NB. Producing a list of boxed anonymous verbs (functions)
┌───┬───┬───┬───┬────┬────┬────┬────┬────┬────┐
┌───┬───┬───┬───┬────┬────┬────┬────┬────┬────┐
│0"_│1"_│4"_│9"_│16"_│25"_│36"_│49"_│64"_│81"_│
│0"_│1"_│4"_│9"_│16"_│25"_│36"_│49"_│64"_│81"_│
Line 985: Line 985:
25"_
25"_
{::&VL 5 '' NB. Invoking the 6th verb with a dummy argument ('')
{::&VL 5 '' NB. Invoking the 6th verb with a dummy argument ('')
25</lang>
25</syntaxhighlight>


=={{header|Java}}==
=={{header|Java}}==
{{works with|Java|8+}}
{{works with|Java|8+}}
<lang java>import java.util.function.Supplier;
<syntaxhighlight lang="java">import java.util.function.Supplier;
import java.util.ArrayList;
import java.util.ArrayList;


Line 1,003: Line 1,003:
System.out.println(foo.get()); // prints "9"
System.out.println(foo.get()); // prints "9"
}
}
}</lang>
}</syntaxhighlight>


Alternative implementation that also {{works with|Java|8+}}
Alternative implementation that also {{works with|Java|8+}}
<lang java>import java.util.List;
<syntaxhighlight lang="java">import java.util.List;
import java.util.function.IntSupplier;
import java.util.function.IntSupplier;
import java.util.stream.IntStream;
import java.util.stream.IntStream;
Line 1,022: Line 1,022:
System.out.println(closure.getAsInt()); // prints "9"
System.out.println(closure.getAsInt()); // prints "9"
}
}
}</lang>
}</syntaxhighlight>


=={{header|JavaScript}}==
=={{header|JavaScript}}==
Line 1,028: Line 1,028:
===Imperative===
===Imperative===


<lang javascript>var funcs = [];
<syntaxhighlight lang="javascript">var funcs = [];
for (var i = 0; i < 10; i++) {
for (var i = 0; i < 10; i++) {
funcs.push( (function(i) {
funcs.push( (function(i) {
Line 1,034: Line 1,034:
})(i) );
})(i) );
}
}
window.alert(funcs[3]()); // alerts "9"</lang>
window.alert(funcs[3]()); // alerts "9"</syntaxhighlight>


{{works with|JavaScript|1.7+}} (Firefox 2+)
{{works with|JavaScript|1.7+}} (Firefox 2+)
<lang javascript><script type="application/javascript;version=1.7">
<syntaxhighlight lang="javascript"><script type="application/javascript;version=1.7">
var funcs = [];
var funcs = [];
for (var i = 0; i < 10; i++) {
for (var i = 0; i < 10; i++) {
Line 1,045: Line 1,045:
}
}
window.alert(funcs[3]()); // alerts "9"
window.alert(funcs[3]()); // alerts "9"
</script></lang>
</script></syntaxhighlight>


{{works with|JavaScript|ES6}}
{{works with|JavaScript|ES6}}
<lang javascript>"use strict";
<syntaxhighlight lang="javascript">"use strict";
let funcs = [];
let funcs = [];
for (let i = 0; i < 10; ++i) {
for (let i = 0; i < 10; ++i) {
funcs.push((i => () => i*i)(i));
funcs.push((i => () => i*i)(i));
}
}
console.log(funcs[3]());</lang>
console.log(funcs[3]());</syntaxhighlight>


===Functional ===
===Functional ===
Line 1,059: Line 1,059:
{{works with|JavaScript|ES5}}
{{works with|JavaScript|ES5}}


<lang javascript>(function () {
<syntaxhighlight lang="javascript">(function () {
'use strict';
'use strict';


Line 1,079: Line 1,079:
return lstFns[3]();
return lstFns[3]();


})();</lang>
})();</syntaxhighlight>


{{out}}
{{out}}
Line 1,087: Line 1,087:


{{works with|JavaScript|ES6}}
{{works with|JavaScript|ES6}}
<lang javascript>let funcs = [...Array(10).keys()].map(i => () => i*i);</lang>
<syntaxhighlight lang="javascript">let funcs = [...Array(10).keys()].map(i => () => i*i);</syntaxhighlight>
{{out}}
{{out}}
<pre>
<pre>
Line 1,095: Line 1,095:


=={{header|Julia}}==
=={{header|Julia}}==
<lang julia>funcs = [ () -> i^2 for i = 1:10 ]</lang>
<syntaxhighlight lang="julia">funcs = [ () -> i^2 for i = 1:10 ]</syntaxhighlight>
{{out}}
{{out}}
<pre>
<pre>
Line 1,103: Line 1,103:


=={{header|Kotlin}}==
=={{header|Kotlin}}==
<lang scala>// version 1.0.6
<syntaxhighlight lang="scala">// version 1.0.6


fun main(args: Array<String>) {
fun main(args: Array<String>) {
Line 1,110: Line 1,110:
// call all but the last
// call all but the last
(0 .. 8).forEach { println(funcs[it]()) }
(0 .. 8).forEach { println(funcs[it]()) }
}</lang>
}</syntaxhighlight>


{{out}}
{{out}}
Line 1,128: Line 1,128:


A translation from Javascript
A translation from Javascript
<lang scheme>
<syntaxhighlight lang="scheme">
{def A
{def A
{A.new
{A.new
Line 1,139: Line 1,139:
{A.get 4 {A}}
{A.get 4 {A}}
-> 16
-> 16
</syntaxhighlight>
</lang>


=={{header|Latitude}}==
=={{header|Latitude}}==
Line 1,145: Line 1,145:
Latitude is particularly well suited to this challenge, as the various iteration constructs actually take method arguments and <i>call</i> them multiple times. Thus, the loop variable is in fact an argument which is already closed over and distinct at each iteration.
Latitude is particularly well suited to this challenge, as the various iteration constructs actually take method arguments and <i>call</i> them multiple times. Thus, the loop variable is in fact an argument which is already closed over and distinct at each iteration.


<lang latitude>functions := 10 times to (Array) map {
<syntaxhighlight lang="latitude">functions := 10 times to (Array) map {
takes '[i].
takes '[i].
proc { (i) * (i). }.
proc { (i) * (i). }.
}.
}.


functions visit { println: $1 call. }.</lang>
functions visit { println: $1 call. }.</syntaxhighlight>


{{Out}}
{{Out}}
Line 1,167: Line 1,167:


Input at the REPL:
Input at the REPL:
<lang lisp>
<syntaxhighlight lang="lisp">
> (set funcs (list-comp ((<- m (lists:seq 1 10)))
> (set funcs (list-comp ((<- m (lists:seq 1 10)))
(lambda () (math:pow m 2))))
(lambda () (math:pow m 2))))
</syntaxhighlight>
</lang>


Output:
Output:
<lang lisp>
<syntaxhighlight lang="lisp">
(#Fun<lfe_eval.23.101079464> #Fun<lfe_eval.23.101079464>
(#Fun<lfe_eval.23.101079464> #Fun<lfe_eval.23.101079464>
#Fun<lfe_eval.23.101079464> #Fun<lfe_eval.23.101079464>
#Fun<lfe_eval.23.101079464> #Fun<lfe_eval.23.101079464>
Line 1,179: Line 1,179:
#Fun<lfe_eval.23.101079464> #Fun<lfe_eval.23.101079464>
#Fun<lfe_eval.23.101079464> #Fun<lfe_eval.23.101079464>
#Fun<lfe_eval.23.101079464> #Fun<lfe_eval.23.101079464>)
#Fun<lfe_eval.23.101079464> #Fun<lfe_eval.23.101079464>)
</syntaxhighlight>
</lang>


Calling the functions:
Calling the functions:
<lang lisp>
<syntaxhighlight lang="lisp">
> (funcall (car funcs))
> (funcall (car funcs))
1.0
1.0
Line 1,192: Line 1,192:
64.0
64.0


</syntaxhighlight>
</lang>


=={{header|Lingo}}==
=={{header|Lingo}}==
Line 1,198: Line 1,198:
Lingo doesn't really support closures. But with the limitations described at [https://www.rosettacode.org/wiki/Function_composition#Lingo Function composition] and based on the fact that Lingo allows to create arbitrary code at runtime, the task can be solved like this:
Lingo doesn't really support closures. But with the limitations described at [https://www.rosettacode.org/wiki/Function_composition#Lingo Function composition] and based on the fact that Lingo allows to create arbitrary code at runtime, the task can be solved like this:


<lang lingo>-- parent script "CallFunction"
<syntaxhighlight lang="lingo">-- parent script "CallFunction"


property _code
property _code
Line 1,221: Line 1,221:
do(me._code)
do(me._code)
return res
return res
end</lang>
end</syntaxhighlight>


<lang lingo>funcs = []
<syntaxhighlight lang="lingo">funcs = []
repeat with i = 1 to 10
repeat with i = 1 to 10
code = "res="&i&"*"&i
code = "res="&i&"*"&i
Line 1,230: Line 1,230:


put call(funcs[3], _movie)
put call(funcs[3], _movie)
-- 9</lang>
-- 9</syntaxhighlight>


Since the original task is a little trivial in terms of not depending on runtime arguments, here also a solution for an extended task: let each function[i] return the square of i plus the sum of all arguments passed to it at runtime:
Since the original task is a little trivial in terms of not depending on runtime arguments, here also a solution for an extended task: let each function[i] return the square of i plus the sum of all arguments passed to it at runtime:


<lang lingo>funcs = []
<syntaxhighlight lang="lingo">funcs = []
repeat with i = 1 to 10
repeat with i = 1 to 10
code = ""
code = ""
Line 1,248: Line 1,248:


put call(funcs[7], _movie, 4, 5, 6)
put call(funcs[7], _movie, 4, 5, 6)
-- 64</lang>
-- 64</syntaxhighlight>


=={{header|Logtalk}}==
=={{header|Logtalk}}==
The example that follow uses Logtalk's native support for lambda expressions.
The example that follow uses Logtalk's native support for lambda expressions.
<lang logtalk>
<syntaxhighlight lang="logtalk">
:- object(value_capture).
:- object(value_capture).


Line 1,268: Line 1,268:


:- end_object.
:- end_object.
</syntaxhighlight>
</lang>
{{out}}
{{out}}
<lang text>
<syntaxhighlight lang="text">
| ?- value_capture::show.
| ?- value_capture::show.
Closure 1 : 1
Closure 1 : 1
Line 1,283: Line 1,283:
Closure 10 : 100
Closure 10 : 100
yes
yes
</syntaxhighlight>
</lang>


=={{header|Lua}}==
=={{header|Lua}}==
<lang Lua>
<syntaxhighlight lang="Lua">
funcs={}
funcs={}
for i=1,10 do
for i=1,10 do
Line 1,293: Line 1,293:
funcs[2]()
funcs[2]()
funcs[3]()
funcs[3]()
</syntaxhighlight>
</lang>
{{out}}
{{out}}
<pre>4
<pre>4
Line 1,300: Line 1,300:


=={{header|M2000 Interpreter}}==
=={{header|M2000 Interpreter}}==
<lang M2000 Interpreter>
<syntaxhighlight lang="M2000 Interpreter">
Dim Base 0, A(10)
Dim Base 0, A(10)
For i=0 to 9 {
For i=0 to 9 {
Line 1,308: Line 1,308:
Print a(i)()
Print a(i)()
}
}
</syntaxhighlight>
</lang>
Print
Print
0
0
Line 1,322: Line 1,322:


Export list to clipboard
Export list to clipboard
<lang M2000 Interpreter>
<syntaxhighlight lang="M2000 Interpreter">
document a$
document a$
For i=0 to 9 {
For i=0 to 9 {
Line 1,329: Line 1,329:
}
}
Clipboard a$
Clipboard a$
</syntaxhighlight>
</lang>


Using Inventory, and a stack object (reading from position, and another way, we pop functions, using Read)
Using Inventory, and a stack object (reading from position, and another way, we pop functions, using Read)




<lang M2000 Interpreter>
<syntaxhighlight lang="M2000 Interpreter">
Inventory Alfa
Inventory Alfa
For i=0 to 9 {
For i=0 to 9 {
Line 1,362: Line 1,362:
}
}


</syntaxhighlight>
</lang>


=={{header|Maple}}==
=={{header|Maple}}==
<lang Maple>> L := map( i -> (() -> i^2), [seq](1..10) ):
<syntaxhighlight lang="Maple">> L := map( i -> (() -> i^2), [seq](1..10) ):
> seq( L[i](),i=1..10);
> seq( L[i](),i=1..10);
1, 4, 9, 16, 25, 36, 49, 64, 81, 100
1, 4, 9, 16, 25, 36, 49, 64, 81, 100
> L[4]();
> L[4]();
16
16
</syntaxhighlight>
</lang>


=={{header|Mathematica}} / {{header|Wolfram Language}}==
=={{header|Mathematica}} / {{header|Wolfram Language}}==
<lang Mathematica>Function[i, i^2 &] /@ Range@10
<syntaxhighlight lang="Mathematica">Function[i, i^2 &] /@ Range@10
->{1^2 &, 2^2 &, 3^2 &, 4^2 &, 5^2 &, 6^2 &, 7^2 &, 8^2 &, 9^2 &, 10^2 &}
->{1^2 &, 2^2 &, 3^2 &, 4^2 &, 5^2 &, 6^2 &, 7^2 &, 8^2 &, 9^2 &, 10^2 &}


%[[2]][]
%[[2]][]
->4</lang>
->4</syntaxhighlight>


=={{header|Nemerle}}==
=={{header|Nemerle}}==
<lang Nemerle>using System.Console;
<syntaxhighlight lang="Nemerle">using System.Console;


module Closures
module Closures
Line 1,392: Line 1,392:
WriteLine($"$(funcs[2]())");
WriteLine($"$(funcs[2]())");
}
}
}</lang>
}</syntaxhighlight>
{{out}}
{{out}}
<pre>16
<pre>16
Line 1,398: Line 1,398:


=={{header|Nim}}==
=={{header|Nim}}==
<lang nim>var funcs: seq[proc(): int] = @[]
<syntaxhighlight lang="nim">var funcs: seq[proc(): int] = @[]


for i in 0..9:
for i in 0..9:
Line 1,406: Line 1,406:


for i in 0..8:
for i in 0..8:
echo "func[", i, "]: ", funcs[i]()</lang>
echo "func[", i, "]: ", funcs[i]()</syntaxhighlight>


=={{header|Objeck}}==
=={{header|Objeck}}==
<lang objeck>use Collection.Generic;
<syntaxhighlight lang="objeck">use Collection.Generic;


class Capture {
class Capture {
Line 1,425: Line 1,425:
}
}
}
}
</syntaxhighlight>
</lang>


{{output}}
{{output}}
Line 1,443: Line 1,443:
=={{header|Objective-C}}==
=={{header|Objective-C}}==
{{works with|Cocoa|Mac OS X 10.6+}} with ARC
{{works with|Cocoa|Mac OS X 10.6+}} with ARC
<lang objc>NSMutableArray *funcs = [[NSMutableArray alloc] init];
<syntaxhighlight lang="objc">NSMutableArray *funcs = [[NSMutableArray alloc] init];
for (int i = 0; i < 10; i++) {
for (int i = 0; i < 10; i++) {
[funcs addObject:[^ { return i * i; } copy]];
[funcs addObject:[^ { return i * i; } copy]];
Line 1,450: Line 1,450:
int (^foo)(void) = funcs[3];
int (^foo)(void) = funcs[3];
NSLog(@"%d", foo()); // logs "9"
NSLog(@"%d", foo()); // logs "9"
</syntaxhighlight>
</lang>


=={{header|OCaml}}==
=={{header|OCaml}}==
Line 1,456: Line 1,456:
All functions in OCaml are closures.
All functions in OCaml are closures.


<lang ocaml>let () =
<syntaxhighlight lang="ocaml">let () =
let cls = Array.init 10 (fun i -> (function () -> i * i)) in
let cls = Array.init 10 (fun i -> (function () -> i * i)) in
Random.self_init ();
Random.self_init ();
Line 1,462: Line 1,462:
let x = Random.int 9 in
let x = Random.int 9 in
Printf.printf " fun.(%d) = %d\n" x (cls.(x) ());
Printf.printf " fun.(%d) = %d\n" x (cls.(x) ());
done</lang>
done</syntaxhighlight>


{{out}}
{{out}}
Line 1,475: Line 1,475:


=={{header|Oforth}}==
=={{header|Oforth}}==
<lang Oforth>: newClosure(i) #[ i sq ] ;
<syntaxhighlight lang="Oforth">: newClosure(i) #[ i sq ] ;
10 seq map(#newClosure) at(7) perform .</lang>
10 seq map(#newClosure) at(7) perform .</syntaxhighlight>


{{out}}
{{out}}
Line 1,485: Line 1,485:
=={{header|PARI/GP}}==
=={{header|PARI/GP}}==
{{works with|PARI/GP|2.4.2 and above}}
{{works with|PARI/GP|2.4.2 and above}}
<lang parigp>vector(10,i,()->i^2)[5]()</lang>
<syntaxhighlight lang="parigp">vector(10,i,()->i^2)[5]()</syntaxhighlight>


{{out}}
{{out}}
Line 1,491: Line 1,491:


=={{header|Perl}}==
=={{header|Perl}}==
<lang perl>my @f = map(sub { $_ * $_ }, 0 .. 9); # @f is an array of subs
<syntaxhighlight lang="perl">my @f = map(sub { $_ * $_ }, 0 .. 9); # @f is an array of subs
print $f[$_](), "\n" for (0 .. 8); # call and print all but last</lang>
print $f[$_](), "\n" for (0 .. 8); # call and print all but last</syntaxhighlight>
{{out}}
{{out}}
<pre>
<pre>
Line 1,508: Line 1,508:
=={{header|Phix}}==
=={{header|Phix}}==
Phix does not support closures, but they seem easy enough to emulate
Phix does not support closures, but they seem easy enough to emulate
<!--<lang Phix>(phixonline)-->
<!--<syntaxhighlight lang="Phix">(phixonline)-->
<span style="color: #008080;">with</span> <span style="color: #008080;">javascript_semantics</span>
<span style="color: #008080;">with</span> <span style="color: #008080;">javascript_semantics</span>
<span style="color: #000080;font-style:italic;">-- First some generic handling stuff, handles partial_args
<span style="color: #000080;font-style:italic;">-- First some generic handling stuff, handles partial_args
Line 1,545: Line 1,545:
<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;">" %d"</span><span style="color: #0000FF;">,</span><span style="color: #000000;">call_closure</span><span style="color: #0000FF;">(</span><span style="color: #000000;">cids</span><span style="color: #0000FF;">[</span><span style="color: #000000;">i</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;">" %d"</span><span style="color: #0000FF;">,</span><span style="color: #000000;">call_closure</span><span style="color: #0000FF;">(</span><span style="color: #000000;">cids</span><span style="color: #0000FF;">[</span><span style="color: #000000;">i</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>
<!--</lang>-->
<!--</syntaxhighlight>-->
{{out}}
{{out}}
<pre>
<pre>
Line 1,559: Line 1,559:


A dictionary based approach may prove somewhat easier:
A dictionary based approach may prove somewhat easier:
<!--<lang Phix>(phixonline)-->
<!--<syntaxhighlight lang="Phix">(phixonline)-->
<span style="color: #008080;">with</span> <span style="color: #008080;">javascript_semantics</span>
<span style="color: #008080;">with</span> <span style="color: #008080;">javascript_semantics</span>
<span style="color: #008080;">function</span> <span style="color: #000000;">square</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: #008080;">function</span> <span style="color: #000000;">square</span><span style="color: #0000FF;">(</span><span style="color: #004080;">integer</span> <span style="color: #000000;">tid</span><span style="color: #0000FF;">)</span>
Line 1,574: Line 1,574:
<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;">" %d"</span><span style="color: #0000FF;">,</span><span style="color: #000000;">square</span><span style="color: #0000FF;">(</span><span style="color: #000000;">tids</span><span style="color: #0000FF;">[</span><span style="color: #000000;">i</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;">" %d"</span><span style="color: #0000FF;">,</span><span style="color: #000000;">square</span><span style="color: #0000FF;">(</span><span style="color: #000000;">tids</span><span style="color: #0000FF;">[</span><span style="color: #000000;">i</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>
<!--</lang>-->
<!--</syntaxhighlight>-->
same output, for both tests
same output, for both tests


=={{header|Phixmonti}}==
=={{header|Phixmonti}}==
<lang Phixmonti>def power2
<syntaxhighlight lang="Phixmonti">def power2
dup *
dup *
enddef
enddef
Line 1,594: Line 1,594:
var i
var i
i get i swap exec print " " print
i get i swap exec print " " print
endfor</lang>
endfor</syntaxhighlight>


=={{header|PHP}}==
=={{header|PHP}}==
{{works with|PHP|5.3+}}
{{works with|PHP|5.3+}}
<lang php><?php
<syntaxhighlight lang="php"><?php
$funcs = array();
$funcs = array();
for ($i = 0; $i < 10; $i++) {
for ($i = 0; $i < 10; $i++) {
Line 1,604: Line 1,604:
}
}
echo $funcs[3](), "\n"; // prints 9
echo $funcs[3](), "\n"; // prints 9
?></lang>
?></syntaxhighlight>


{{works with|PHP|pre-5.3}}
{{works with|PHP|pre-5.3}}
This method can capture value types like numbers, strings, arrays, etc., but not objects.
This method can capture value types like numbers, strings, arrays, etc., but not objects.
<lang php><?php
<syntaxhighlight lang="php"><?php
$funcs = array();
$funcs = array();
for ($i = 0; $i < 10; $i++) {
for ($i = 0; $i < 10; $i++) {
Line 1,614: Line 1,614:
}
}
echo $funcs[3](), "\n"; // prints 9
echo $funcs[3](), "\n"; // prints 9
?></lang>
?></syntaxhighlight>


=={{header|PicoLisp}}==
=={{header|PicoLisp}}==
<lang PicoLisp>(setq FunList
<syntaxhighlight lang="PicoLisp">(setq FunList
(make
(make
(for @N 10
(for @N 10
(link (curry (@N) () (* @N @N))) ) ) )</lang>
(link (curry (@N) () (* @N @N))) ) ) )</syntaxhighlight>
Test:
Test:
<pre>: ((get FunList 2))
<pre>: ((get FunList 2))
Line 1,629: Line 1,629:


=={{header|Pike}}==
=={{header|Pike}}==
<lang Pike>array funcs = ({});
<syntaxhighlight lang="Pike">array funcs = ({});
foreach(enumerate(10);; int i)
foreach(enumerate(10);; int i)
{
{
Line 1,641: Line 1,641:
}(i)
}(i)
});
});
}</lang>
}</syntaxhighlight>


=={{header|PowerShell}}==
=={{header|PowerShell}}==
I'm not sure that I understood the question/task. This task seems to be the same as the 'Accumulator Factory' task.
I'm not sure that I understood the question/task. This task seems to be the same as the 'Accumulator Factory' task.
<lang PowerShell>
<syntaxhighlight lang="PowerShell">
function Get-Closure ([double]$Number)
function Get-Closure ([double]$Number)
{
{
{param([double]$Sum) return $script:Number *= $Sum}.GetNewClosure()
{param([double]$Sum) return $script:Number *= $Sum}.GetNewClosure()
}
}
</syntaxhighlight>
</lang>
<lang PowerShell>
<syntaxhighlight lang="PowerShell">
for ($i = 1; $i -lt 11; $i++)
for ($i = 1; $i -lt 11; $i++)
{
{
Line 1,661: Line 1,661:
}
}
}
}
</syntaxhighlight>
</lang>
{{Out}}
{{Out}}
<pre>
<pre>
Line 1,677: Line 1,677:
10 100
10 100
</pre>
</pre>
<lang PowerShell>
<syntaxhighlight lang="PowerShell">
$numbers = 1..20 | Get-Random -Count 10
$numbers = 1..20 | Get-Random -Count 10


Line 1,689: Line 1,689:
}
}
}
}
</syntaxhighlight>
</lang>
{{Out}}
{{Out}}
<pre>
<pre>
Line 1,710: Line 1,710:
'''lambda.pl''' can be found there : http://www.complang.tuwien.ac.at/ulrich/Prolog-inedit/lambda.pl
'''lambda.pl''' can be found there : http://www.complang.tuwien.ac.at/ulrich/Prolog-inedit/lambda.pl


<lang Prolog>:-use_module(library(lambda)).
<syntaxhighlight lang="Prolog">:-use_module(library(lambda)).




Line 1,724: Line 1,724:
call(F, R),
call(F, R),
format('Func ~w : ~w~n', [N, R]).
format('Func ~w : ~w~n', [N, R]).
</syntaxhighlight>
</lang>
{{out}}
{{out}}
<pre> ?- closure.
<pre> ?- closure.
Line 1,742: Line 1,742:
=={{header|Python}}==
=={{header|Python}}==
The naive way does not work:
The naive way does not work:
<lang python>funcs = []
<syntaxhighlight lang="python">funcs = []
for i in range(10):
for i in range(10):
funcs.append(lambda: i * i)
funcs.append(lambda: i * i)
print funcs[3]() # prints 81</lang>
print funcs[3]() # prints 81</syntaxhighlight>


The simplest solution is to add optional parameters with default arguments at the end of the parameter list, to create a local copy of the variable, and evaluate the variable at the time the function is created. (The optional parameter is not expected to ever be passed.) Often, the optional parameter will be named the same as the variable to be closed over (leading to odd-looking code of the form <code>foo=foo</code> in the arguments), so that the code inside the function need not be changed, but this might lead to confusion. This technique does not work for functions with a variable number of arguments.
The simplest solution is to add optional parameters with default arguments at the end of the parameter list, to create a local copy of the variable, and evaluate the variable at the time the function is created. (The optional parameter is not expected to ever be passed.) Often, the optional parameter will be named the same as the variable to be closed over (leading to odd-looking code of the form <code>foo=foo</code> in the arguments), so that the code inside the function need not be changed, but this might lead to confusion. This technique does not work for functions with a variable number of arguments.
<lang python>funcs = []
<syntaxhighlight lang="python">funcs = []
for i in range(10):
for i in range(10):
funcs.append(lambda i=i: i * i)
funcs.append(lambda i=i: i * i)
print funcs[3]() # prints 9</lang>
print funcs[3]() # prints 9</syntaxhighlight>
or equivalently the list comprehension:
or equivalently the list comprehension:
<lang python>funcs = [lambda i=i: i * i for i in range(10)]
<syntaxhighlight lang="python">funcs = [lambda i=i: i * i for i in range(10)]
print funcs[3]() # prints 9</lang>
print funcs[3]() # prints 9</syntaxhighlight>


Another solution is to wrap an immediately-executed function around our function. The wrapping function creates a new scope, and its execution forces the evaluation of the variable to be closed over.
Another solution is to wrap an immediately-executed function around our function. The wrapping function creates a new scope, and its execution forces the evaluation of the variable to be closed over.
<lang python>funcs = []
<syntaxhighlight lang="python">funcs = []
for i in range(10):
for i in range(10):
funcs.append((lambda i: lambda: i * i)(i))
funcs.append((lambda i: lambda: i * i)(i))
print funcs[3]() # prints 9</lang>
print funcs[3]() # prints 9</syntaxhighlight>
or equivalently the list comprehension:
or equivalently the list comprehension:
<lang python>funcs = [(lambda i: lambda: i)(i * i) for i in range(10)]
<syntaxhighlight lang="python">funcs = [(lambda i: lambda: i)(i * i) for i in range(10)]
print funcs[3]() # prints 9</lang>
print funcs[3]() # prints 9</syntaxhighlight>


In this case it is also possible to use <code>map()</code> since the function passed to it creates a new scope
In this case it is also possible to use <code>map()</code> since the function passed to it creates a new scope
<lang python>funcs = map(lambda i: lambda: i * i, range(10))
<syntaxhighlight lang="python">funcs = map(lambda i: lambda: i * i, range(10))
print funcs[3]() # prints 9</lang>
print funcs[3]() # prints 9</syntaxhighlight>


It is also possible to use <code>eval</code>.
It is also possible to use <code>eval</code>.
<lang python>funcs=[eval("lambda:%s"%i**2)for i in range(10)]
<syntaxhighlight lang="python">funcs=[eval("lambda:%s"%i**2)for i in range(10)]
print funcs[3]() # prints 9</lang>
print funcs[3]() # prints 9</syntaxhighlight>


=={{header|Quackery}}==
=={{header|Quackery}}==
Line 1,777: Line 1,777:
Strictly speaking, we could get away with <code>[ table 0 1 4 9 16 25 36 49 64 81 ] is functions ( n --> n )</code> for this task, as numbers in Quackery are functions that return their own value when executed, e.g <code>5 do</code> returns <code>5</code>, but it feels like cheating.
Strictly speaking, we could get away with <code>[ table 0 1 4 9 16 25 36 49 64 81 ] is functions ( n --> n )</code> for this task, as numbers in Quackery are functions that return their own value when executed, e.g <code>5 do</code> returns <code>5</code>, but it feels like cheating.


<lang Quackery> [ table ] is functions ( n --> [ )
<syntaxhighlight lang="Quackery"> [ table ] is functions ( n --> [ )


10 times
10 times
Line 1,783: Line 1,783:
' functions put ]
' functions put ]


5 functions do echo</lang>
5 functions do echo</syntaxhighlight>


{{out}}
{{out}}
Line 1,796: Line 1,796:
what you expect.
what you expect.


<syntaxhighlight lang="R">
<lang R>
# assign 's' a list of ten functions
# assign 's' a list of ten functions
s <- sapply (1:10, # integers 1..10 become argument 'x' below
s <- sapply (1:10, # integers 1..10 become argument 'x' below
Line 1,806: Line 1,806:
s[[5]]() # call the fifth function in the list of returned functions
s[[5]]() # call the fifth function in the list of returned functions
[1] 25 # returns vector of length 1 with the value 25
[1] 25 # returns vector of length 1 with the value 25
</syntaxhighlight>
</lang>


Note that I bound the captured variable as the default argument on a unary function.
Note that I bound the captured variable as the default argument on a unary function.
Line 1,812: Line 1,812:
ignores the default argument.
ignores the default argument.


<syntaxhighlight lang="R">
<lang R>
s[[5]](10)
s[[5]](10)
[1] 100
[1] 100
</syntaxhighlight>
</lang>


As a further technicality, note that you need some extra voodoo to '''modify''' the bound argument
As a further technicality, note that you need some extra voodoo to '''modify''' the bound argument
with persistence across calls. This example increments the bound variable after each call.
with persistence across calls. This example increments the bound variable after each call.


<syntaxhighlight lang="R">
<lang R>
s <- sapply (1:10,
s <- sapply (1:10,
function (x) {
function (x) {
Line 1,839: Line 1,839:
s[[1]]()
s[[1]]()
[1] 4 # now 2^2
[1] 4 # now 2^2
</syntaxhighlight>
</lang>


As shown, each instance increments separately.
As shown, each instance increments separately.
Line 1,848: Line 1,848:
I think that modifying the bound variable can be done in a simpler way.
I think that modifying the bound variable can be done in a simpler way.
Instead of:
Instead of:
<lang R> evalq (x <- x + 1, parent.env(environment()))</lang>
<syntaxhighlight lang="R"> evalq (x <- x + 1, parent.env(environment()))</syntaxhighlight>
substitute:
substitute:
<lang R> x <<- x + 1</lang>
<syntaxhighlight lang="R"> x <<- x + 1</syntaxhighlight>
Testing:
Testing:
<pre>
<pre>
Line 1,868: Line 1,868:


=={{header|Racket}}==
=={{header|Racket}}==
<lang racket>
<syntaxhighlight lang="racket">
#lang racket
#lang racket
(define functions (for/list ([i 10]) (λ() (* i i))))
(define functions (for/list ([i 10]) (λ() (* i i))))
(map (λ(f) (f)) functions)
(map (λ(f) (f)) functions)
</syntaxhighlight>
</lang>
{{out}}
{{out}}
<lang racket>
<syntaxhighlight lang="racket">
'(0 1 4 9 16 25 36 49 64 81)
'(0 1 4 9 16 25 36 49 64 81)
</syntaxhighlight>
</lang>


=={{header|Raku}}==
=={{header|Raku}}==
Line 1,882: Line 1,882:
{{Works with|Rakudo|2015.12}}
{{Works with|Rakudo|2015.12}}
All blocks are anonymous closures in Raku, and parameters are lexicals, so it's easy to generate a list of them. We'll use a <tt>gather</tt>/<tt>take</tt> generator loop, and call the closures in random order, just to keep things interesting.
All blocks are anonymous closures in Raku, and parameters are lexicals, so it's easy to generate a list of them. We'll use a <tt>gather</tt>/<tt>take</tt> generator loop, and call the closures in random order, just to keep things interesting.
<lang perl6>my @c = gather for ^10 -> $i {
<syntaxhighlight lang="raku" line>my @c = gather for ^10 -> $i {
take { $i * $i }
take { $i * $i }
}
}


.().say for @c.pick(*); # call them in random order</lang>
.().say for @c.pick(*); # call them in random order</syntaxhighlight>
{{out}}
{{out}}
<pre>36
<pre>36
Line 1,899: Line 1,899:
49</pre>
49</pre>
Or equivalently, using a more functional notation:
Or equivalently, using a more functional notation:
<lang perl6>say .() for pick *, map -> $i { -> {$i * $i} }, ^10</lang>
<syntaxhighlight lang="raku" line>say .() for pick *, map -> $i { -> {$i * $i} }, ^10</syntaxhighlight>


=={{header|Red}}==
=={{header|Red}}==
<lang Red>
<syntaxhighlight lang="Red">
funs: collect [repeat i 10 [keep func [] reduce [i ** 2]]]
funs: collect [repeat i 10 [keep func [] reduce [i ** 2]]]


>> funs/7
>> funs/7
== 49
== 49
</syntaxhighlight>
</lang>


=={{header|REXX}}==
=={{header|REXX}}==
Line 1,917: Line 1,917:


No error checking is performed on the user input(s).
No error checking is performed on the user input(s).
<lang rexx>/*REXX program has a list of ten functions, each returns its invocation (index) squared.*/
<syntaxhighlight lang="rexx">/*REXX program has a list of ten functions, each returns its invocation (index) squared.*/
parse arg seed base $ /*obtain optional arguments from the CL*/
parse arg seed base $ /*obtain optional arguments from the CL*/
if datatype(seed, 'W') then call random ,,seed /*Not given? Use random start seed. */
if datatype(seed, 'W') then call random ,,seed /*Not given? Use random start seed. */
Line 1,941: Line 1,941:
.9: return .(9) /* ' .9 " " " " */
.9: return .(9) /* ' .9 " " " " */
/*──────────────────────────────────────────────────────────────────────────────────────*/
/*──────────────────────────────────────────────────────────────────────────────────────*/
.: arg #; _=wordpos(#,$); if _==0 then return 'not in the list.'; return (_-(\base))**2</lang>
.: arg #; _=wordpos(#,$); if _==0 then return 'not in the list.'; return (_-(\base))**2</syntaxhighlight>
{{out|output|text=&nbsp; when using the default input &nbsp; which assume a zero─based list):}}
{{out|output|text=&nbsp; when using the default input &nbsp; which assume a zero─based list):}}
<pre>
<pre>
Line 1,954: Line 1,954:


=={{header|Ring}}==
=={{header|Ring}}==
<lang ring>
<syntaxhighlight lang="ring">
x = funcs(7)
x = funcs(7)
see x + nl
see x + nl
Line 1,964: Line 1,964:
next
next
return fn
return fn
</syntaxhighlight>
</lang>
Output:
Output:
<pre>
<pre>
Line 1,977: Line 1,977:


=={{header|Ruby}}==
=={{header|Ruby}}==
<lang ruby>procs = Array.new(10){|i| ->{i*i} } # -> creates a lambda
<syntaxhighlight lang="ruby">procs = Array.new(10){|i| ->{i*i} } # -> creates a lambda
p procs[7].call # => 49</lang>
p procs[7].call # => 49</syntaxhighlight>


In Ruby, lambdas (and procs) are closures.
In Ruby, lambdas (and procs) are closures.
Line 1,986: Line 1,986:
Rust employs strong ownership rules that do not allow mutating a value that is referenced (pointed to without allowing mutation) from elsewhere. It also doesn't allow referencing a value that may be dropped before the reference is released. The proof that we really did capture the value is therefore unnecessary. Either we did or it wouldn't have compiled.
Rust employs strong ownership rules that do not allow mutating a value that is referenced (pointed to without allowing mutation) from elsewhere. It also doesn't allow referencing a value that may be dropped before the reference is released. The proof that we really did capture the value is therefore unnecessary. Either we did or it wouldn't have compiled.


<lang rust>fn main() {
<syntaxhighlight lang="rust">fn main() {
let fs: Vec<_> = (0..10).map(|i| {move || i*i} ).collect();
let fs: Vec<_> = (0..10).map(|i| {move || i*i} ).collect();
println!("7th val: {}", fs[7]());
println!("7th val: {}", fs[7]());
}</lang>
}</syntaxhighlight>


{{out}}
{{out}}
Line 1,995: Line 1,995:


=={{header|Scala}}==
=={{header|Scala}}==
<lang scala>val closures=for(i <- 0 to 9) yield (()=>i*i)
<syntaxhighlight lang="scala">val closures=for(i <- 0 to 9) yield (()=>i*i)
0 to 8 foreach (i=> println(closures(i)()))
0 to 8 foreach (i=> println(closures(i)()))
println("---\n"+closures(7)())</lang>
println("---\n"+closures(7)())</syntaxhighlight>
{{out}}
{{out}}
<pre>0
<pre>0
Line 2,013: Line 2,013:
=={{header|Scheme}}==
=={{header|Scheme}}==


<lang scheme>;;; Collecting lambdas in a tail-recursive function.
<syntaxhighlight lang="scheme">;;; Collecting lambdas in a tail-recursive function.
(define (build-list-of-functions n i list)
(define (build-list-of-functions n i list)
(if (< i n)
(if (< i n)
Line 2,023: Line 2,023:
(map (lambda (f) (f)) list-of-functions)
(map (lambda (f) (f)) list-of-functions)


((list-ref list-of-functions 8))</lang>
((list-ref list-of-functions 8))</syntaxhighlight>


{{out}}
{{out}}
<lang scheme>'(1 4 9 16 25 36 49 64 81)
<syntaxhighlight lang="scheme">'(1 4 9 16 25 36 49 64 81)
81</lang>
81</syntaxhighlight>


----
----


Using Scheme [http://srfi.schemers.org/srfi-1/srfi-1.html SRFI 1] ''iota'' procedure can be simplified to:
Using Scheme [http://srfi.schemers.org/srfi-1/srfi-1.html SRFI 1] ''iota'' procedure can be simplified to:
<lang scheme>
<syntaxhighlight lang="scheme">
(define list-of-functions (map (lambda (x) (lambda () (* x x))) (iota 0 1 10)))
(define list-of-functions (map (lambda (x) (lambda () (* x x))) (iota 0 1 10)))


Line 2,039: Line 2,039:
(map (lambda (n) (n)) list-of-functions)
(map (lambda (n) (n)) list-of-functions)
(newline)
(newline)
</syntaxhighlight>
</lang>


=={{header|Sidef}}==
=={{header|Sidef}}==
<lang ruby>var f = (
<syntaxhighlight lang="ruby">var f = (
10.of {|i| func(j){i * j} }
10.of {|i| func(j){i * j} }
)
)
Line 2,048: Line 2,048:
9.times { |j|
9.times { |j|
say f[j](j)
say f[j](j)
}</lang>
}</syntaxhighlight>
{{out}}
{{out}}
<pre>
<pre>
Line 2,063: Line 2,063:


Starting from i=1:
Starting from i=1:
<lang ruby>var f = (1..10).map { |i|
<syntaxhighlight lang="ruby">var f = (1..10).map { |i|
func(j){i * j}
func(j){i * j}
}
}
Line 2,069: Line 2,069:
for j (1..9) {
for j (1..9) {
say f[j-1](j)
say f[j-1](j)
}</lang>
}</syntaxhighlight>
{{out}}
{{out}}
<pre>
<pre>
Line 2,084: Line 2,084:


=={{header|Smalltalk}}==
=={{header|Smalltalk}}==
<lang smalltalk>funcs := (1 to: 10) collect: [ :i | [ i * i ] ] .
<syntaxhighlight lang="smalltalk">funcs := (1 to: 10) collect: [ :i | [ i * i ] ] .
(funcs at: 3) value displayNl .</lang>
(funcs at: 3) value displayNl .</syntaxhighlight>
{{out}}
{{out}}
<pre>9</pre>
<pre>9</pre>
Line 2,092: Line 2,092:
In Sparkling, upvalues (variables in the closure) are captured by value.
In Sparkling, upvalues (variables in the closure) are captured by value.


<lang sparkling>var fnlist = {};
<syntaxhighlight lang="sparkling">var fnlist = {};
for var i = 0; i < 10; i++ {
for var i = 0; i < 10; i++ {
fnlist[i] = function() {
fnlist[i] = function() {
Line 2,100: Line 2,100:


print(fnlist[3]()); // prints 9
print(fnlist[3]()); // prints 9
print(fnlist[5]()); // prints 25</lang>
print(fnlist[5]()); // prints 25</syntaxhighlight>


Alternately:
Alternately:


<lang sparkling>var fnlist = map(range(10), function(k, v) {
<syntaxhighlight lang="sparkling">var fnlist = map(range(10), function(k, v) {
return function() {
return function() {
return v * v;
return v * v;
Line 2,111: Line 2,111:


print(fnlist[3]()); // prints 9
print(fnlist[3]()); // prints 9
print(fnlist[5]()); // prints 25</lang>
print(fnlist[5]()); // prints 25</syntaxhighlight>


=={{header|Standard ML}}==
=={{header|Standard ML}}==
<lang Standard ML>
<syntaxhighlight lang="Standard ML">
List.map (fn x => x () ) ( List.tabulate (10,(fn i => (fn ()=> i*i)) ) ) ;
List.map (fn x => x () ) ( List.tabulate (10,(fn i => (fn ()=> i*i)) ) ) ;
</lang> Output:
</syntaxhighlight> Output:
<lang Standard ML>
<syntaxhighlight lang="Standard ML">
val it = [0,1,4,9,16,25,36,49,64,81] : int list
val it = [0,1,4,9,16,25,36,49,64,81] : int list
</syntaxhighlight>
</lang>


=={{header|Swift}}==
=={{header|Swift}}==
By default, Swift captures variables by reference. A naive implementation like the following C-style for loop does not work:
By default, Swift captures variables by reference. A naive implementation like the following C-style for loop does not work:
<lang swift>var funcs: [() -> Int] = []
<syntaxhighlight lang="swift">var funcs: [() -> Int] = []
for var i = 0; i < 10; i++ {
for var i = 0; i < 10; i++ {
funcs.append({ i * i })
funcs.append({ i * i })
}
}
println(funcs[3]()) // prints 100</lang>
println(funcs[3]()) // prints 100</syntaxhighlight>


However, using a for-in loop over a range does work, since you get a new constant at every iteration:
However, using a for-in loop over a range does work, since you get a new constant at every iteration:
<lang swift>var funcs: [() -> Int] = []
<syntaxhighlight lang="swift">var funcs: [() -> Int] = []
for i in 0..<10 {
for i in 0..<10 {
funcs.append({ i * i })
funcs.append({ i * i })
}
}
println(funcs[3]()) // prints 9</lang>
println(funcs[3]()) // prints 9</syntaxhighlight>


The C-style for loop can also work if we explicitly capture the loop counter:
The C-style for loop can also work if we explicitly capture the loop counter:
<lang swift>var funcs: [() -> Int] = []
<syntaxhighlight lang="swift">var funcs: [() -> Int] = []
for var i = 0; i < 10; i++ {
for var i = 0; i < 10; i++ {
funcs.append({ [i] in i * i })
funcs.append({ [i] in i * i })
}
}
println(funcs[3]()) // prints 9</lang>
println(funcs[3]()) // prints 9</syntaxhighlight>


Alternately, we can also use <code>map()</code> to map over a range, and create the squaring closure inside the mapping closure which has the integer as a parameter:
Alternately, we can also use <code>map()</code> to map over a range, and create the squaring closure inside the mapping closure which has the integer as a parameter:
<lang swift>let funcs = [] + map(0..<10) {i in { i * i }}
<syntaxhighlight lang="swift">let funcs = [] + map(0..<10) {i in { i * i }}
println(funcs[3]()) // prints 9</lang>
println(funcs[3]()) // prints 9</syntaxhighlight>


=={{header|Tcl}}==
=={{header|Tcl}}==
Tcl does not support closures (either value-capturing or variable-capturing) by default, but value-capturing closures are easy to emulate.
Tcl does not support closures (either value-capturing or variable-capturing) by default, but value-capturing closures are easy to emulate.
<lang tcl>package require Tcl 8.6; # Just for tailcall command
<syntaxhighlight lang="tcl">package require Tcl 8.6; # Just for tailcall command
# Builds a value-capturing closure; does NOT couple variables
# Builds a value-capturing closure; does NOT couple variables
proc closure {script} {
proc closure {script} {
Line 2,184: Line 2,184:
set idx [expr {int(rand()*9)}]; # pick random int from [0..9)
set idx [expr {int(rand()*9)}]; # pick random int from [0..9)
puts $idx=>[{*}[lindex $theClosures $idx]]
puts $idx=>[{*}[lindex $theClosures $idx]]
}</lang>
}</syntaxhighlight>
{{out}}
{{out}}
<pre>
<pre>
Line 2,198: Line 2,198:
====Sugared====
====Sugared====


<lang txrlisp>(let ((funs (mapcar (ret (op * @@1 @@1)) (range 1 10))))
<syntaxhighlight lang="txrlisp">(let ((funs (mapcar (ret (op * @@1 @@1)) (range 1 10))))
[mapcar call [funs 0..-1]])</lang>
[mapcar call [funs 0..-1]])</syntaxhighlight>


{{out}}
{{out}}


<lang txrlisp>(1 4 9 16 25 36 49 64 81)</lang>
<syntaxhighlight lang="txrlisp">(1 4 9 16 25 36 49 64 81)</syntaxhighlight>


====Desugared====
====Desugared====
Line 2,211: Line 2,211:
The explicit <code>lambda</code> structure here is much like the implicit ones in the "Sugared" example:
The explicit <code>lambda</code> structure here is much like the implicit ones in the "Sugared" example:


<lang txrlisp>;; Dropping distracting "skip last" requirement
<syntaxhighlight lang="txrlisp">;; Dropping distracting "skip last" requirement
;; (not implemented in original Elisp either).
;; (not implemented in original Elisp either).
(mapcar 'call
(mapcar 'call
(mapcar (lambda ()
(mapcar (lambda ()
(lambda () (* x x))) '(1 2 3 4 5 6 7 8 9 10)))</lang>
(lambda () (* x x))) '(1 2 3 4 5 6 7 8 9 10)))</syntaxhighlight>


====Delimited Continuations====
====Delimited Continuations====
Line 2,255: Line 2,255:


=={{header|Wren}}==
=={{header|Wren}}==
<lang ecmascript>var fs = List.filled(10, null)
<syntaxhighlight lang="ecmascript">var fs = List.filled(10, null)
for (i in 0...fs.count) {
for (i in 0...fs.count) {
fs[i] = Fn.new { i * i }
fs[i] = Fn.new { i * i }
}
}


for (i in 0...fs.count-1) System.print("Function #%(i): %(fs[i].call())")</lang>
for (i in 0...fs.count-1) System.print("Function #%(i): %(fs[i].call())")</syntaxhighlight>


{{out}}
{{out}}
Line 2,276: Line 2,276:


=={{header|Yabasic}}==
=={{header|Yabasic}}==
<lang Yabasic>
<syntaxhighlight lang="Yabasic">
dim funcs$(10)
dim funcs$(10)


Line 2,290: Line 2,290:
print execute(funcs$(i), i)
print execute(funcs$(i), i)
next
next
</syntaxhighlight>
</lang>


=={{header|zkl}}==
=={{header|zkl}}==
Create a closure of the index over a square function
Create a closure of the index over a square function
<lang zkl>(0).pump(10,List,fcn(i){i*i}.fp)[8]() //-->64
<syntaxhighlight lang="zkl">(0).pump(10,List,fcn(i){i*i}.fp)[8]() //-->64
list:=(0).pump(10,List,fcn(i){i*i}.fp);
list:=(0).pump(10,List,fcn(i){i*i}.fp);
foreach n in (list.len()-1) { list[n]().println() }
foreach n in (list.len()-1) { list[n]().println() }
list.run(True).println()</lang>
list.run(True).println()</syntaxhighlight>
{{out}}
{{out}}
<pre>
<pre>