28 lines
770 B
Factor
28 lines
770 B
Factor
! Copyright (C) 2008, 2010 Doug Coleman, Slava Pestov.
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! See http://factorcode.org/license.txt for BSD license.
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USING: classes classes.algebra.private classes.predicate
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classes.predicate.private kernel sequences words ;
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IN: classes.singleton
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<PRIVATE
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: singleton-predicate-quot ( class -- quot ) [ eq? ] curry ;
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PRIVATE>
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PREDICATE: singleton-class < predicate-class
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[ "predicate-definition" word-prop ]
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[ singleton-predicate-quot ]
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bi sequence= ;
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: define-singleton-class ( word -- )
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\ word over singleton-predicate-quot 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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M: singleton-class predicate-quot
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singleton-predicate-quot ;
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