145 lines
		
	
	
		
			4.0 KiB
		
	
	
	
		
			Factor
		
	
	
			
		
		
	
	
			145 lines
		
	
	
		
			4.0 KiB
		
	
	
	
		
			Factor
		
	
	
! Copyright (C) 2009 Daniel Ehrenberg.
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! See http://factorcode.org/license.txt for BSD license.
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USING: regexp.classes kernel sequences regexp.negation
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quotations assocs fry math locals combinators
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accessors words compiler.units kernel.private strings
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sequences.private arrays namespaces unicode.breaks
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regexp.transition-tables combinators.short-circuit ;
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IN: regexp.compiler
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GENERIC: question>quot ( question -- quot )
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SYMBOL: shortest?
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SYMBOL: backwards?
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<PRIVATE
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M: t question>quot drop [ 2drop t ] ;
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M: f question>quot drop [ 2drop f ] ;
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M: beginning-of-input question>quot
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    drop [ drop zero? ] ;
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M: end-of-input question>quot
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    drop [ length = ] ;
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M: end-of-file question>quot
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    drop [
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        {
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            [ length swap - 2 <= ]
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            [ swap tail { "\n" "\r\n" "\r" "" } member? ]
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        } 2&&
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    ] ;
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M: $ question>quot
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    drop [ { [ length = ] [ ?nth "\r\n" member? ] } 2|| ] ;
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M: ^ question>quot
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    drop [ { [ drop zero? ] [ [ 1 - ] dip ?nth "\r\n" member? ] } 2|| ] ;
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M: $unix question>quot
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    drop [ { [ length = ] [ ?nth CHAR: \n = ] } 2|| ] ;
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M: ^unix question>quot
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    drop [ { [ drop zero? ] [ [ 1 - ] dip ?nth CHAR: \n = ] } 2|| ] ;
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M: word-break question>quot
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    drop [ word-break-at? ] ;
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: (execution-quot) ( next-state -- quot )
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    ! The conditions here are for lookaround and anchors, etc
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    dup condition? [
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        [ question>> question>quot ] [ yes>> ] [ no>> ] tri
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        [ (execution-quot) ] bi@
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        '[ 2dup @ _ _ if ]
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    ] [ '[ _ execute ] ] if ;
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: execution-quot ( next-state -- quot )
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    dup sequence? [ first ] when
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    (execution-quot) ;
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TUPLE: box contents ;
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C: <box> box
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: condition>quot ( condition -- quot )
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    ! Conditions here are for different classes
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    dup condition? [
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        [ question>> ] [ yes>> ] [ no>> ] tri
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        [ condition>quot ] bi@
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        '[ dup _ class-member? _ _ if ]
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    ] [
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        contents>>
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        [ [ 3drop ] ] [ execution-quot '[ drop @ ] ] if-empty
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    ] if ;
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: non-literals>dispatch ( literals non-literals  -- quot )
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    [ swap ] assoc-map ! we want state => predicate, and get the opposite as input
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    swap keys f assoc-answers
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    table>condition [ <box> ] condition-map condition>quot ;
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: literals>cases ( literal-transitions -- case-body )
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    [ execution-quot ] assoc-map ;
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: split-literals ( transitions -- case default )
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    { } assoc-like [ first integer? ] partition
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    [ [ literals>cases ] keep ] dip non-literals>dispatch ;
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: advance ( index backwards? -- index+/-1 )
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    -1 1 ? + >fixnum ; inline
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: check ( index string backwards? -- in-bounds? )
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    [ drop -1 eq? not ] [ length < ] if ; inline
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:: step ( last-match index str quot final? backwards? -- last-index/f )
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    final? index last-match ?
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    index str backwards? check [
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        index backwards? advance str
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        index str nth-unsafe
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        quot call
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    ] when ; inline
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: transitions>quot ( transitions final-state? -- quot )
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    dup shortest? get and [ 2drop [ drop nip ] ] [
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        [ split-literals swap case>quot ] dip backwards? get
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        '[ { fixnum string } declare _ _ _ step ]
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    ] if ;
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: word>quot ( word dfa -- quot )
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    [ transitions>> at ]
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    [ final-states>> key? ] 2bi
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    transitions>quot ;
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: states>code ( words dfa -- )
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    '[
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        dup _ word>quot
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        (( last-match index string -- ? ))
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        define-declared
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    ] each ;
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: states>words ( dfa -- words dfa )
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    dup transitions>> keys [ gensym ] H{ } map>assoc
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    [ transitions-at ]
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    [ values ]
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    bi swap ; 
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: dfa>main-word ( dfa -- word )
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    states>words [ states>code ] keep start-state>> ;
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: word-template ( quot -- quot' )
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    '[ drop [ f ] 2dip over array-capacity? _ [ 2drop ] if ] ;
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PRIVATE>
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: dfa>word ( dfa -- quot )
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    dfa>main-word execution-quot word-template
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    (( start-index string regexp -- i/f )) define-temp ;
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: dfa>shortest-word ( dfa -- word )
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    t shortest? [ dfa>word ] with-variable ;
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: dfa>reverse-word ( dfa -- word )
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    t backwards? [ dfa>word ] with-variable ;
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: dfa>reverse-shortest-word ( dfa -- word )
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    t backwards? [ dfa>shortest-word ] with-variable ;
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