1 ! Copyright (C) 2009 Daniel Ehrenberg
2 ! See http://factorcode.org/license.txt for BSD license.
3 USING: kernel sequences regexp.transition-tables fry assocs
4 accessors locals math sorting arrays sets hashtables regexp.dfa
5 combinators.short-circuit regexp.classes ;
8 : table>state-numbers ( table -- assoc )
9 transitions>> keys <enum> [ swap ] H{ } assoc-map-as ;
11 : number-states ( table -- newtable )
12 dup table>state-numbers transitions-at ;
14 : has-conditions? ( assoc -- ? )
15 values [ condition? ] any? ;
17 : initially-same? ( s1 s2 transition-table -- ? )
20 [ transitions>> '[ _ at keys ] bi@ set= ]
21 [ final-states>> '[ _ in? ] bi@ = ]
24 :: initialize-partitions ( transition-table -- partitions )
25 ! Partition table is sorted-array => ?
27 transition-table transitions>> keys :> states
30 s1 s2 transition-table initially-same?
31 [ s1 s2 2array out conjoin ] when
35 : same-partition? ( s1 s2 partitions -- ? )
36 { [ [ sort-pair 2array ] dip key? ] [ drop = ] } 3|| ;
38 : assemble-values ( assoc1 assoc2 -- values )
39 dup keys '[ _ swap [ at ] curry map ] bi@ zip ;
41 : stay-same? ( s1 s2 transition partitions -- ? )
42 [ '[ _ transitions>> at ] bi@ assemble-values ] dip
43 '[ _ same-partition? ] assoc-all? ;
45 : partition-more ( partitions transition-table -- partitions )
46 over '[ drop first2 _ _ stay-same? ] assoc-filter ;
48 : partition>classes ( partitions -- synonyms ) ! old-state => new-state
50 [ drop first2 swap ] assoc-map
54 :: (while-changes) ( ..a obj quot: ( ..a obj -- ..b obj' ) comp: ( ..b obj' -- ..a key ) old-key -- ..a obj )
55 obj quot call :> new-obj
56 new-obj comp call :> new-key
59 [ new-obj quot comp new-key (while-changes) ]
62 : while-changes ( obj quot pred -- obj' )
63 3dup nip call (while-changes) ; inline
65 : (state-classes) ( transition-table -- partition )
66 [ initialize-partitions ] keep
67 '[ _ partition-more ] [ assoc-size ] while-changes ;
69 : assoc>set ( assoc -- keys-set )
70 [ drop dup ] assoc-map ;
72 : state-classes ( transition-table -- synonyms )
73 clone [ [ nip has-conditions? ] assoc-partition ] change-transitions
74 [ assoc>set ] [ (state-classes) partition>classes ] bi* assoc-union ;
76 : canonical-state? ( state transitions state-classes -- ? )
77 '[ dup _ at = ] swap '[ _ at has-conditions? ] bi or ;
79 : delete-duplicates ( transitions state-classes -- new-transitions )
80 dupd '[ drop _ _ canonical-state? ] assoc-filter ;
82 : combine-states ( table -- smaller-table )
84 [ transitions-at ] keep
85 '[ _ delete-duplicates ] change-transitions ;
87 : combine-state-transitions ( hash -- hash )
88 [ H{ } clone ] dip over '[
89 _ [ 2array <or-class> ] change-at
90 ] assoc-each [ swap ] assoc-map ;
92 : combine-transitions ( table -- table )
93 [ [ combine-state-transitions ] assoc-map ] change-transitions ;
95 : minimize ( table -- minimal-table )