factor/core/classes/union/union.factor

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Factor
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! Copyright (C) 2004, 2008 Slava Pestov.
! See http://factorcode.org/license.txt for BSD license.
USING: words sequences kernel assocs combinators classes
classes.algebra namespaces arrays math quotations ;
IN: classes.union
PREDICATE: union-class < class
"metaclass" word-prop union-class eq? ;
: union-predicate-quot ( members -- quot )
[
[ drop f ]
] [
unclip "predicate" word-prop swap [
"predicate" word-prop [ dup ] prepend
[ drop t ]
] { } map>assoc alist>quot
] if-empty ;
: define-union-predicate ( class -- )
dup members union-predicate-quot define-predicate ;
M: union-class update-class define-union-predicate ;
: (define-union-class) ( class members -- )
f swap f union-class define-class ;
: define-union-class ( class members -- )
[ (define-union-class) ] [ drop update-classes ] 2bi ;
M: union-class rank-class drop 2 ;
M: union-class instance?
"members" word-prop [ instance? ] with any? ;
M: union-class (flatten-class)
members <anonymous-union> (flatten-class) ;