68 lines
2.2 KiB
Factor
68 lines
2.2 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: accessors arrays assocs fry kernel locals math math.bits
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regexp.ast regexp.classes regexp.transition-tables sequences
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sets ;
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IN: regexp.disambiguate
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TUPLE: parts in out ;
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: make-partition ( choices classes -- partition )
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zip [ first ] partition [ values ] bi@ parts boa ;
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: powerset-partition ( sequence -- partitions )
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[ length [ 2^ <iota> ] keep ] keep '[ _ <bits> _ make-partition ] map rest ;
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: partition>class ( parts -- class )
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[ out>> [ <not-class> ] map ]
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[ in>> <and-class> ] bi prefix <and-class> ;
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: singleton-partition ( integer non-integers -- {class,partition} )
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dupd
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'[ _ [ class-member? ] with filter ] keep
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prefix f parts boa
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2array ;
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: add-out ( seq partition -- partition' )
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[ nip in>> ] [ out>> append ] 2bi parts boa ;
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: intersection ( seq -- elts/f )
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[ f ] [ [ ] [ intersect ] map-reduce ] if-empty ;
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: meaningful-integers ( partition table -- integers )
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[ [ in>> ] [ out>> ] bi ] dip
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'[ [ _ at ] map intersection ] bi@ diff ;
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: class-integers ( classes integers -- table )
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'[ _ over '[ _ class-member? ] filter ] H{ } map>assoc ;
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: add-integers ( partitions classes integers -- partitions )
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class-integers '[
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[ _ meaningful-integers ] [ ] bi add-out
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] map ;
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:: class-partitions ( classes -- assoc )
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classes [ integer? ] partition :> ( integers classes )
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classes powerset-partition classes integers add-integers
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[ [ partition>class ] [ ] bi 2array ] map sift-keys
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integers [ classes singleton-partition ] map append ;
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: new-transitions ( transitions -- assoc ) ! assoc is class, partition
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values [ keys ] gather [ tagged-epsilon? ] reject class-partitions ;
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: get-transitions ( partition state-transitions -- next-states )
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[ in>> ] dip '[ _ at ] gather sift ;
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: disambiguate ( nfa -- nfa )
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expand-ors [
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dup new-transitions '[
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[
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_ swap '[ _ get-transitions ] assoc-map
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harvest-values
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] [
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[ drop tagged-epsilon? ] assoc-filter
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] bi H{ } assoc-union-as
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] assoc-map
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] change-transitions ;
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