start implementing subgroups
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173
regex.tal
173
regex.tal
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@ -38,16 +38,24 @@
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( dot matches any one char [ #02 next* ] )
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( lit matches one specific char (c) [ #03 c^ next* ] )
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( or matches either left or right [ #04 left* right* ] )
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( star matches expr zero-or-more times [ #05 r* next* ] )
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( star matches expr zero-or-more times [ #05 expr* next* ] )
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( (NOTE: r.expr.next must be r) )
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( )
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( caret matches start of line/string [ #06 next* ] )
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( dollar matches end of line/string [ #07 next* ] )
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( lpar starts subgroup region [ #08 i* next* ] )
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( rpar ends subgroup region [ #09 i* next* ] )
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( )
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( `or` and `star` have the same structure and are handled by the )
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( same code (;do-or). however, the node types are kept different )
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( to make it clearer how to parse and assemble the nodes. )
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( )
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( dollar nodes contain a next pointer even though this usually )
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( will not be needed. )
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( )
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( lpar and rpar contain addresses pointing between subgroup-bot )
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( and subgroup-bot. rpar's address will always be +2 relative to )
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( the corresponding lpar address. )
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( )
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( concatenation isn't a node, it is implied by the *next addr. )
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( a next value of #0000 signals the end of the regex. )
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( )
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@ -55,6 +63,15 @@
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( regexes should not include nulls and cannot match them (other )
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( than the null which signals the end of a string). )
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( TODO: we have lpar and rpar nodes but aren't using them yet )
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( 1. need to modify c-lpar and c-par )
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( 2. we need to store subgroup-posd in regions during parsing: )
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( a. need to store the current pos in the region )
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( b. need to call start to move subgroup-pos forward )
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( 3. when finishing parsing a region we need lpar/rpar nodes )
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( 4. we also need to store "last started subgroup" on the stack )
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( 5. when backtracking we must rewind to "last started" subgroup )
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%debug { #ff #0e DEO }
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%emit { #18 DEO }
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%space { #20 emit }
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@ -144,6 +161,8 @@
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LDAk #05 EQU ;do-or JCN2 ( same code as the or case )
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LDAk #06 EQU ;do-caret JCN2
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LDAk #07 EQU ;do-dollar JCN2
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LDAk #08 EQU ;do-lpar JCN2
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LDAk #09 EQU ;do-rpar JCN2
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;unknown-node-type ;error! JSR2
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( used when we hit a dead-end during matching. )
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@ -169,28 +188,46 @@
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INC2 LDA2 ( load next )
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;goto-next JMP2 ( jump to next )
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@do-lpar ( str* regex* -> bool^ )
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STH2 DUP2 ( s s [r] )
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INC2r LDA2kr STH2r ( s s i [r+1] )
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;subgroup-start JSR2 ( s [r+1] )
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STH2r INC2 INC2 ( s r+3 )
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LDA2 ;goto-next JMP2 ( jump to next )
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@do-rpar ( str* regex* -> bool^ )
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STH2 DUP2 ( s s [r] )
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INC2r LDA2kr STH2r ( s s i [r+1] )
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;subgroup-finish JSR2 ( s [r+1] )
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STH2r INC2 INC2 ( s r+3 )
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LDA2 ;goto-next JMP2 ( jump to next )
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( handle dot -- match any one character )
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@do-dot ( str* regex* -> bool^ )
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INC2 LDA2 STH2 ( load and stash next )
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LDAk #00 NEQ ,&non-empty JCN ( is there a char? )
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INC2 LDA2 STH2 ( load and stash next )
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LDAk #00 NEQ ,&non-empty JCN ( is there a char? )
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&backtrack POP2r POP2 ;goto-backtrack JMP2 ( no, clear stacks and backtrack )
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&non-empty LDAk #0a NEQ ,&match JCN ( yes, match unless \n in search-mode )
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;search-mode LDA ,&backtrack JCN ( if \n and search-mode, treat as EOF )
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&match INC2 STH2r ;goto-next JMP2 ( on match: inc s, restore and jump )
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&non-empty LDAk #0a NEQ ,&match JCN ( yes, match unless \n in search-mode )
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;search-mode LDA ,&backtrack JCN ( if \n and search-mode, treat as EOF )
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&match INC2 STH2r ;goto-next JMP2 ( on match: inc s, restore and jump )
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( TODO: support multi-line=0 )
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( hande caret -- match string start (or possibly after newline) without advancing )
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@do-caret ( str* regex* -> bool^ )
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INC2 LDA2 STH2 ( load and stash next )
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INC2 LDA2 STH2 ( load and stash next )
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DUP2 ;string-start LDA2 EQU2 ,&at-start JCN ( at string start? )
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POP2r POP2 ;goto-backtrack JMP2 ( no, clear stacks and backtrack )
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&at-start STH2r ;goto-next JMP2 ( yes, goto next without advancing str )
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;match-multiline LDA ,&no-match JCN ( are we in multi-line mode? )
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#0001 SUB2 LDAk #0a EQU ,&at-start JCN ( just after newline? )
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&no-match POP2r POP2 ;goto-backtrack JMP2 ( clear stacks and backtrack )
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&at-start STH2r ;goto-next JMP2 ( go to next without advancing )
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( TODO: support multi-line=0 )
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( hande dollar -- match string end (or possibly before newline) without advancing )
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@do-dollar ( str* regex* -> bool^ )
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INC2 LDA2 STH2 ( load and stash next )
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LDAk #00 EQU ,&at-end JCN ( at string end? )
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POP2r POP2 ;goto-backtrack JMP2 ( no, clear stacks and backtrack )
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&at-end STH2r ;goto-next JMP2 ( yes, goto next without advancing str )
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INC2 LDA2 STH2 ( load and stash next )
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LDAk #00 EQU ,&at-end JCN ( at string end? )
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;match-multiline LDA ,&no-match JCN ( are we in multi-line mode? )
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LDAk #0a EQU ,&at-end JCN ( at newline? )
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&no-match POP2r POP2 ;goto-backtrack JMP2 ( clear stacks and backtrack )
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&at-end STH2r ;goto-next JMP2 ( go to next without advancing )
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( handle literal -- match one specific character )
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@do-literal ( str* regex* -> bool^ )
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@ -229,17 +266,6 @@
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@search-start $2
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@search-end $2
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(
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( used for subgroup match start/end addresses )
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@groups [ &s0 $2 &e0 $2 &s1 $2 &e1 $2
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&s2 $2 &e2 $2 &s3 $2 &e3 $2
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&s4 $2 &e4 $2 &s5 $2 &e5 $2
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&s6 $2 &e6 $2 &s7 $2 &e7 $2
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&s8 $2 &e8 $2 &s9 $2 &e9 $2 ]
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( position of last finished group )
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@group-pos $2 )
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( track the position in the input string )
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@pos $2
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@ -397,7 +423,7 @@
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( allocates a dot-node and continues. )
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@c-dot ( c^ -> r2* )
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POP
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;alloc-dot JSR2 ( dot )
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#02 ;alloc3 JSR2
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DUP2 ;c-peek-and-finalize JMP2
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( called when we read "^" )
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@ -405,7 +431,7 @@
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( allocates a caret-node and continues. )
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@c-caret ( c^ -> r2* )
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POP
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;alloc-caret JSR2 ( caret )
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#06 ;alloc3 JMP2
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DUP2 ;c-peek-and-finalize JMP2
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( called when we read "$" )
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@ -413,7 +439,7 @@
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( allocates a dollar-node and continues. )
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@c-dollar ( c^ -> r2* )
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POP
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;alloc-dollar JSR2 ( dollar )
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#07 ;alloc3 JMP2
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DUP2 ;c-peek-and-finalize JMP2
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( called when we read "\" )
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@ -479,15 +505,6 @@
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@alloc-empty ( -> r* )
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#01 ;alloc3 JMP2
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@alloc-dot ( -> r* )
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#02 ;alloc3 JMP2
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@alloc-caret ( -> r* )
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#06 ;alloc3 JMP2
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@alloc-dollar ( -> r* )
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#07 ;alloc3 JMP2
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@alloc-lit ( c^ -> r* )
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#03 #0000 SWP2 ( 0000 c^ 03 )
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#04 ;alloc JSR2 ( 0000 c^ 03 addr* )
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@ -584,16 +601,23 @@
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&is-zero STA2 JMP2r
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( set regex.next to target )
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( )
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( node types 1-7 are defined. )
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( )
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( all node types except star (5) and lit (3) store their next )
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( pointer one byte off of their own address. )
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( )
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( since both branches of an or (4) node are supposed to meet )
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( back up we only bother taking the left branch. otherwise )
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( you can end up double-appending things. )
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@set-next ( target* regex* -> )
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LDAk #01 NEQ ,&!1 JCN INC2 ;set-next-addr JSR2 JMP2r
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&!1 LDAk #02 NEQ ,&!2 JCN INC2 ;set-next-addr JSR2 JMP2r
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&!2 LDAk #03 NEQ ,&!3 JCN #0002 ADD2 ;set-next-addr JSR2 JMP2r
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&!3 LDAk #04 NEQ ,&!4 JCN INC2 ;set-next-addr JSR2 JMP2r
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&!4 LDAk #05 NEQ ,&!5 JCN #0003 ADD2 ;set-next-addr JSR2 JMP2r
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( &!5 ;unknown-node-type ;error! JSR2 )
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&!5 LDAk #06 NEQ ,&!6 JCN INC2 ;set-next-addr JSR2 JMP2r
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&!6 LDAk #07 NEQ ,&!7 JCN INC2 ;set-next-addr JSR2 JMP2r
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&!7 ;unknown-node-type ;error! JSR2
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LDAk #01 LTH ,&unknown JCN
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LDAk #07 GTH ,&unknown JCN
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LDAk #05 NEQ ,&!5 JCN #0003 ADD2 ,&continue JMP
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&!5 LDAk #03 NEQ ,&!3 JCN #0002 ADD2 ,&continue JMP
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&!3 INC2
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&continue ;set-next-addr JSR2 JMP2r
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&unknown ;unknown-node-type ;error! JSR2
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@set-next-or-addr ( target* addr* -> )
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LDA2k #0000 EQU2 ( target addr addr=0? ) ,&is-zero JCN
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@ -711,6 +735,59 @@
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@arena-pos :arena-bot ( the next position to allocate )
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@arena-bot $400 @arena-top ( holds up to 1024 bytes )
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( SUBGROUP OPERATIONS )
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( )
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( subgroups are parts of the input string that are matched by )
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( parenthesized subgroup expressions in a regex. )
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( )
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( for example, (a*)(b*)(c*) has 3 subgroup expressions. )
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( )
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( during matching, subgroups are represented by 4-bytes )
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( which are interpreted as two short values: )
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( )
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( - bytes 0-1: absolute address of the start of the subgroup )
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( - bytes 2-3: absolute address of the limit of the subgroup )
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( )
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( this means that to get a null-terminated subgroup string )
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( you will need to copy it somewhere else with enough space, )
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( or else mutate the input string to add a null. )
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( )
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( since input strings themselves are null-terminated, and since )
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( subgroups never include null terminators, we will always have )
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( a valid limit value even for input strings that end at #ffff. )
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( )
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( during regex parsing we will use subgroup-pos to track the )
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( next available subgroup position. )
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@subgroup-start ( s* i* -> )
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DUP2 ;subgroup-pos LDA2 LTH2 ,&write JCN ( s i )
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DUP2 #0004 ADD2 ;subgroup-pos STA2 ( s i )
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&write STA2 JMP2r
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@subgroup-finish ( s* i* -> )
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STA2 JMP2r
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@subgroup-backtrack ( i* -> )
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;subgroup-pos LDA2
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&loop #0004 SUB2
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LTH2k ,&done JCN
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#0000 OVR2 STA2
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#0000 OVR2 #0002 ADD2 STA2
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,&loop JMP
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&done POP2 ;subgroup-pos STA2
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JMP2r
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@subgroup-reset ( -> )
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;subgroup-bot ;subgroup-pos STA2
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;subgroup-top ;subgroup-bot LIT2r 0000
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&loop GTH2k ,&continue JCN
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POP2 POP2 POP2r JMP2r
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&continue STH2kr OVR2 STA2
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INC2 INC2 ,&loop JMP
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@subgroup-pos :subgroup-bot ( the position of the first unallocated subgroup )
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@subgroup-bot $800 @subgroup-top ( holds up to 512 subgroups (2048 bytes) )
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( INTERVAL OPERATIONS )
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( )
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( not baked yet )
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