54 lines
1.8 KiB
Factor
54 lines
1.8 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.nfa regexp.disambiguate kernel sequences
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assocs regexp.classes hashtables accessors fry vectors
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regexp.ast regexp.transition-tables regexp.minimize
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regexp.dfa namespaces ;
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IN: regexp.negation
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CONSTANT: fail-state -1
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: add-default-transition ( state's-transitions -- new-state's-transitions )
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clone dup
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[ [ fail-state ] dip keys [ <not-class> ] map <and-class> ] keep set-at ;
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: fail-state-recurses ( transitions -- new-transitions )
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clone dup
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[ fail-state t associate fail-state ] dip set-at ;
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: add-fail-state ( transitions -- new-transitions )
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[ add-default-transition ] assoc-map
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fail-state-recurses ;
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: inverse-final-states ( transition-table -- final-states )
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[ transitions>> assoc>set ] [ final-states>> ] bi assoc-diff ;
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: negate-table ( transition-table -- transition-table )
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clone
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[ add-fail-state ] change-transitions
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dup inverse-final-states >>final-states ;
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: renumber-states ( transition-table -- transition-table )
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dup transitions>> keys [ next-state ] H{ } map>assoc
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transitions-at ;
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: box-transitions ( transition-table -- transition-table )
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[ [ [ 1vector ] assoc-map ] assoc-map ] change-transitions ;
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: unify-final-state ( transition-table -- transition-table )
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dup [ final-states>> keys ] keep
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'[ -2 epsilon _ set-transition ] each
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H{ { -2 -2 } } >>final-states ;
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: adjoin-dfa ( transition-table -- start end )
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unify-final-state renumber-states box-transitions
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[ start-state>> ]
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[ final-states>> keys first ]
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[ nfa-table get [ transitions>> ] bi@ swap update ] tri ;
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: ast>dfa ( parse-tree -- minimal-dfa )
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construct-nfa disambiguate construct-dfa minimize ;
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M: negation nfa-node ( node -- start end )
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term>> ast>dfa negate-table adjoin-dfa ;
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