56 lines
		
	
	
		
			1.5 KiB
		
	
	
	
		
			Factor
		
	
	
		
			Executable File
		
	
			
		
		
	
	
			56 lines
		
	
	
		
			1.5 KiB
		
	
	
	
		
			Factor
		
	
	
		
			Executable File
		
	
! Copyright (C) 2007 Slava Pestov, Daniel Ehrenberg.
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! See http://factorcode.org/license.txt for BSD license.
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USING: kernel hashtables sequences arrays words namespaces
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parser math assocs effects definitions quotations ;
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IN: memoize
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: packer ( n -- quot )
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    { [ f ] [ ] [ 2array ] [ 3array ] [ 4array ] } nth ;
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: unpacker ( n -- quot )
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    { [ drop ] [ ] [ first2 ] [ first3 ] [ first4 ] } nth ;
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: #in ( word -- n )
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    stack-effect effect-in length ;
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: #out ( word -- n )
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    stack-effect effect-out length ;
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: pack/unpack ( quot word -- newquot )
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    [ dup #in unpacker % swap % #out packer % ] [ ] make ;
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: make-memoizer ( quot word -- quot )
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    [
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        [ #in packer % ] keep
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        [ "memoize" word-prop , ] keep
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        [ pack/unpack , ] keep
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        \ cache ,
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        #out unpacker %
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    ] [ ] make ;
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: check-memoized ( word -- )
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    dup #in 4 > swap #out 4 > or [
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        "There must be no more than 4 input and 4 output arguments" throw
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    ] when ;
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: define-memoized ( word quot -- )
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    over check-memoized
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    2dup "memo-quot" set-word-prop
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    over H{ } clone "memoize" set-word-prop
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    over make-memoizer define ;
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: MEMO:
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    CREATE dup reset-generic parse-definition define-memoized ; parsing
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PREDICATE: word memoized "memoize" word-prop ;
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M: memoized definer drop \ MEMO: \ ; ;
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M: memoized definition "memo-quot" word-prop ;
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: memoize-quot ( quot effect -- memo-quot )
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    gensym swap dupd "declared-effect" set-word-prop
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    dup rot define-memoized 1quotation ;
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: reset-memoized ( word -- )
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    "memoize" word-prop clear-assoc ;
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