factor/extra/concurrency/flags/flags.factor

23 lines
565 B
Factor
Executable File

! Copyright (C) 2008 Slava Pestov.
! See http://factorcode.org/license.txt for BSD license.
USING: boxes kernel threads ;
IN: concurrency.flags
TUPLE: flag value? thread ;
: <flag> ( -- flag ) f <box> flag construct-boa ;
: raise-flag ( flag -- )
dup flag-value? [
t over set-flag-value?
dup flag-thread [ resume ] if-box?
] unless drop ;
: wait-for-flag ( flag -- )
dup flag-value? [ drop ] [
[ flag-thread >box ] curry "flag" suspend drop
] if ;
: lower-flag ( flag -- )
dup wait-for-flag f swap set-flag-value? ;