46 lines
		
	
	
		
			1.2 KiB
		
	
	
	
		
			Factor
		
	
	
			
		
		
	
	
			46 lines
		
	
	
		
			1.2 KiB
		
	
	
	
		
			Factor
		
	
	
! Copyright (C) 2004, 2010 Slava Pestov.
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! See http://factorcode.org/license.txt for BSD license.
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USING: words sequences kernel assocs combinators classes
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classes.algebra classes.algebra.private namespaces arrays math
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quotations ;
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IN: classes.union
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PREDICATE: union-class < class
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    "metaclass" word-prop union-class eq? ;
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<PRIVATE
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: union-predicate-quot ( members -- quot )
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    [
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        [ drop f ]
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    ] [
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        unclip "predicate" word-prop swap [
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            "predicate" word-prop [ dup ] prepend
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            [ drop t ]
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        ] { } map>assoc alist>quot
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    ] if-empty ;
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: define-union-predicate ( class -- )
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    dup members union-predicate-quot define-predicate ;
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M: union-class update-class define-union-predicate ;
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: (define-union-class) ( class members -- )
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    f swap f union-class define-class ;
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PRIVATE>
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: define-union-class ( class members -- )
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    [ (define-union-class) ] [ drop update-classes ] 2bi ;
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M: union-class rank-class drop 2 ;
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M: union-class instance?
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    "members" word-prop [ instance? ] with any? ;
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M: union-class normalize-class
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    members <anonymous-union> normalize-class ;
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M: union-class (flatten-class)
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    members <anonymous-union> (flatten-class) ;
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