! Copyright (C) 2005, 2008 Chris Double, Slava Pestov.
! See http://factorcode.org/license.txt for BSD license.
USING: concurrency.promises concurrency.messaging kernel arrays
continuations help.markup help.syntax quotations ;
IN: concurrency.futures

HELP: future
{ $values { "quot" "a quotation with stack effect " { $snippet "( -- value )" } } { "future" future } }
{ $description "Creates a deferred computation."
$nl
"The quotation begins with an empty data stack, an empty catch stack, and a name stack containing the global namespace only. This means that the only way to pass data to the quotation is to partially apply the data, for example using " { $link curry } " or " { $link compose } "." } ;

HELP: ?future-timeout
{ $values { "future" future } { "timeout" "a timeout in milliseconds or " { $link f } } { "value" object } }
{ $description "Waits for a deferred computation to complete, blocking indefinitely if " { $snippet "timeout" } " is " { $link f } ", otherwise waiting up to " { $snippet "timeout" } " milliseconds." }
{ $errors "Throws an error if the timeout expires before the computation completes. Also throws an error if the future quotation threw an error." } ;

HELP: ?future
{ $values { "future" future } { "value" object } }
{ $description "Waits for a deferred computation to complete, blocking indefinitely." }
{ $errors "Throws an error if future quotation threw an error." } ;

ARTICLE: "concurrency.futures" "Futures"
"The " { $vocab-link "concurrency.futures" } " vocabulary implements " { $emphasis "futures" } ", which are deferred computations performed in a background thread. A thread may create a future, then proceed to perform other tasks, then later wait for the future to complete."
{ $subsection future }
{ $subsection ?future }
{ $subsection ?future-timeout } ;

ABOUT: "concurrency.futures"