factor/basis/concurrency/promises/promises.factor

27 lines
730 B
Factor

! Copyright (C) 2005, 2008 Chris Double, Slava Pestov.
! See http://factorcode.org/license.txt for BSD license.
USING: accessors concurrency.mailboxes kernel continuations ;
IN: concurrency.promises
TUPLE: promise mailbox ;
: <promise> ( -- promise )
<mailbox> promise boa ;
: promise-fulfilled? ( promise -- ? )
mailbox>> mailbox-empty? not ;
ERROR: promise-already-fulfilled promise ;
: fulfill ( value promise -- )
dup promise-fulfilled? [
promise-already-fulfilled
] [
mailbox>> mailbox-put
] if ;
: ?promise-timeout ( promise timeout -- result )
[ mailbox>> ] dip block-if-empty mailbox-peek ;
: ?promise ( promise -- result )
f ?promise-timeout ;