57 lines
		
	
	
		
			1.7 KiB
		
	
	
	
		
			Factor
		
	
	
			
		
		
	
	
			57 lines
		
	
	
		
			1.7 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 accessors sequences kernel assocs combinators
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| classes classes.private classes.algebra classes.algebra.private
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| classes.builtin namespaces arrays math quotations ;
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| IN: classes.intersection
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| 
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| PREDICATE: intersection-class < class
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|     "metaclass" word-prop intersection-class eq? ;
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| 
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| <PRIVATE
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| 
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| : intersection-predicate-quot ( members -- quot )
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|     [
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|         [ drop t ]
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|     ] [
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|         unclip "predicate" word-prop swap [
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|             "predicate" word-prop [ dup ] [ not ] surround
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|             [ drop f ]
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|         ] { } map>assoc alist>quot
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|     ] if-empty ;
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| 
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| : define-intersection-predicate ( class -- )
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|     dup participants intersection-predicate-quot define-predicate ;
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| 
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| M: intersection-class update-class define-intersection-predicate ;
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| 
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| M: intersection-class rank-class drop 2 ;
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| 
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| M: intersection-class instance?
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|     "participants" word-prop [ instance? ] with all? ;
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| 
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| M: intersection-class normalize-class
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|     participants <anonymous-intersection> normalize-class ;
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| 
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| M: intersection-class (flatten-class)
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|     participants <anonymous-intersection> (flatten-class) ;
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| 
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| ! Horribly inefficient and inaccurate
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| : intersect-flattened-classes ( seq1 seq2 -- seq3 )
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|     ! Only keep those in seq1 that intersect something in seq2.
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|     [ [ classes-intersect? ] with any? ] curry filter ;
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| 
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| M: anonymous-intersection (flatten-class)
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|     participants>> [ full-cover ] [
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|         [ flatten-class keys ]
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|         [ intersect-flattened-classes ] map-reduce
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|         [ dup set ] each
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|     ] if-empty ;
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| 
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| PRIVATE>
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| 
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| : define-intersection-class ( class participants -- )
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|     [ [ f f ] dip intersection-class define-class ]
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|     [ drop update-classes ]
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|     2bi ;
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