86 lines
2.5 KiB
Factor
86 lines
2.5 KiB
Factor
! Copyright (C) 2008 Doug Coleman.
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! See http://factorcode.org/license.txt for BSD license.
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USING: accessors assocs combinators combinators.lib kernel
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math math.ranges quotations sequences regexp2.parser
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regexp2.classes combinators.short-circuit assocs.lib
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sequences.lib regexp2.utils ;
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IN: regexp2.traversal
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TUPLE: dfa-traverser
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dfa-table
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traversal-flags
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capture-groups
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{ capture-group-index integer }
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{ lookahead-counter integer }
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last-state current-state
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text
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start-index current-index
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matches ;
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: <dfa-traverser> ( text regexp -- match )
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[ dfa-table>> ] [ traversal-flags>> ] bi
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dfa-traverser new
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swap >>traversal-flags
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swap [ start-state>> >>current-state ] keep
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>>dfa-table
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swap >>text
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0 >>start-index
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0 >>current-index
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V{ } clone >>matches
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V{ } clone >>capture-groups ;
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: final-state? ( dfa-traverser -- ? )
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[ current-state>> ] [ dfa-table>> final-states>> ] bi
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key? ;
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: text-finished? ( dfa-traverser -- ? )
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[ current-index>> ] [ text>> length ] bi >= ;
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: save-final-state ( dfa-straverser -- )
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[ current-index>> ] [ matches>> ] bi push ;
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: match-done? ( dfa-traverser -- ? )
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dup final-state? [
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dup save-final-state
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] when text-finished? ;
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: increment-state ( dfa-traverser state -- dfa-traverser )
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>r [ 1+ ] change-current-index dup current-state>> >>last-state r>
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first >>current-state ;
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: match-failed ( dfa-traverser -- dfa-traverser )
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V{ } clone >>matches ;
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: match-literal ( transition from-state table -- to-state/f )
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transitions>> [ at ] [ 2drop f ] if-at ;
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: match-class ( transition from-state table -- to-state/f )
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transitions>> at* [
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[ drop class-member? ] assoc-with assoc-find [ nip ] [ drop ] if
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] [ drop ] if ;
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: match-default ( transition from-state table -- to-state/f )
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[ nip ] dip transitions>>
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[ t swap [ drop f ] unless-at ] [ drop f ] if-at ;
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: match-transition ( obj from-state dfa -- to-state/f )
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{ [ match-literal ] [ match-class ] [ match-default ] } 3|| ;
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: setup-match ( match -- obj state dfa-table )
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{
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[ current-index>> ] [ text>> ]
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[ current-state>> ] [ dfa-table>> ]
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} cleave
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[ nth ] 2dip ;
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: do-match ( dfa-traverser -- dfa-traverser )
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dup match-done? [
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dup setup-match match-transition
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[ increment-state do-match ] when*
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] unless ;
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: return-match ( dfa-traverser -- interval/f )
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dup matches>>
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[ drop f ]
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[ [ start-index>> ] [ peek ] bi* 1 <range> ] if-empty ;
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