Editing Continuation (section)

===Programming language support===
Many programming languages exhibit first-class continuations under various names; specifically:
*[[Common Lisp]]: [http://common-lisp.net/project/cl-cont/ cl-cont]. One can also use custom macros
*[[C Sharp (programming language)|C#]] / [[VB.NET]]: <code>async</code> and <code>await</code>: "sign up the rest of method as the continuation, and then return to your caller immediately; the task will invoke the continuation when it completes". [http://msdn.microsoft.com/en-us/vstudio/gg316360 Asynchronous Programming for C#]
*[[Factor (programming language)|Factor]]: <code>callcc0</code> and <code>callcc1</code>
*[[Haskell (programming language)|Haskell]]: The Continuation [[Monad (functional programming)|monad]] in <code>[http://hackage.haskell.org/packages/archive/mtl/2.0.1.0/doc/html/Control-Monad-Cont.html Control.Monad.Cont]</code>
*[[Haxe]]: [https://github.com/Atry/haxe-continuation haxe-continuation]
*[[Icon (programming language)|Icon]], [[Unicon (programming language)|Unicon]] : <code>create, suspend, @</code> operator: coexpressions
*[[Java (programming language)|Java]]: [http://lightwolf.sourceforge.net/index.html Lightwolf] [http://commons.apache.org/sandbox/commons-javaflow/ javaflow] (requires bytecode manipulation at runtime or compile time)
*[[Kotlin (programming language)|Kotlin]] : <code>Continuation</code>
*[[Rhino (JavaScript engine)|JavaScript Rhino]] : <code>Continuation</code>
*[[Parrot virtual machine|Parrot]]: <code>Continuation</code> PMC; uses [[continuation-passing style]] for all control flow
*[[Perl]]: [https://metacpan.org/module/Coro Coro] and [https://metacpan.org/module/Continuity Continuity]
*[[Pico (programming language)|Pico]]: <code>call(exp())</code> and <code>continue(aContinuation, anyValue)</code>
*[[Python (programming language)|Python]]: [[PyPy]]'s <code>[https://web.archive.org/web/20231217182002/https://doc.pypy.org/en/latest/stackless.html#continulets _continuation.continulets]</code>
*[[Racket (programming language)|Racket]]: <code>[[call-with-current-continuation]]</code> (commonly shortened to <code>call/cc</code>)
*[[Ruby (programming language)|Ruby]]: <code>callcc</code>
*[[Scala (programming language)|Scala]]: <code>scala.util.continuations</code> provides <code>shift</code>/<code>reset</code>
*[[Scheme (programming language)|Scheme]]: <code>[[call-with-current-continuation]]</code> (commonly shortened to <code>call/cc</code>)
*[[Smalltalk]]: <code>Continuation currentDo:</code>; in most modern Smalltalk environments continuations can be implemented without additional VM support.
*[[Standard ML of New Jersey]]: <code>SMLofNJ.Cont.callcc</code>
*[[Unlambda]]: <code>c</code>, the flow control operation for call with current continuation
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Please do not re-add the following entries:
*Python: generators are not first-class continuations
*Stackless Python: provides tasklets/coroutines only;  first-class continuations were a target for the first implementation, but dropped
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In any language which supports [[closure (computer science)|closures]] and [[tail recursion|proper tail calls]], it is possible to write programs in [[continuation-passing style]] and manually implement call/cc.  (In continuation-passing style, call/cc becomes a simple function that can be written with [[lambda calculus|lambda]].)  This is a particularly common strategy in [[Haskell (programming language)|Haskell]], where it is easy to construct a "continuation-passing [[Monad (functional programming)|monad]]" (for example, the <code>Cont</code> monad and <code>ContT</code> monad transformer in the <code>mtl</code> library). The support for [[tail recursion|proper tail calls]] is needed because in continuation-passing style no function ever returns; ''all'' calls are tail calls.