18 lines
542 B
Factor
18 lines
542 B
Factor
! Copyright (C) 2008 Doug Coleman.
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! See http://factorcode.org/license.txt for BSD license.
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USING: classes classes.algebra classes.predicate kernel
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sequences words ;
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IN: classes.singleton
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PREDICATE: singleton-class < predicate-class
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[ "predicate-definition" word-prop ]
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[ [ eq? ] curry ] bi sequence= ;
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: define-singleton-class ( word -- )
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\ word over [ eq? ] curry define-predicate-class ;
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M: singleton-class instance? eq? ;
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M: singleton-class (classes-intersect?)
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over singleton-class? [ eq? ] [ call-next-method ] if ;
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