1: \ Regexp compile
2:
3: \ The idea of the parser is the following:
4: \ As long as there's a match, continue
5: \ On a mismatch, LEAVE.
6: \ Insert appropriate control structures on alternative branches
7: \ Keep the old pointer (backtracking) on the stack
8: \ I try to keep the syntax as close to a real regexp system as possible
9: \ All regexp stuff is compiled into one function as forward branching
10: \ state machine
11:
12: \ bulk-postponing
13:
14: : FORK ( compilation -- orig ; run-time f -- ) \ core
15: POSTPONE call >mark ; immediate restrict
16: : JOIN ( orig -- ) postpone THEN ; immediate restrict
17:
18: \ Charclasses
19:
20: : +bit ( addr n -- ) + 1 swap c! ;
21: : -bit ( addr n -- ) + 0 swap c! ;
22: : @+ ( addr -- n addr' ) dup @ swap cell+ ;
23:
24: 0 Value cur-class
25: : charclass ( -- ) Create here dup to cur-class $100 dup allot erase ;
26: : +char ( char -- ) cur-class swap +bit ;
27: : -char ( char -- ) cur-class swap -bit ;
28: : ..char ( start end -- ) 1+ swap ?DO I +char LOOP ;
29: : or! ( n addr -- ) dup @ rot or swap ! ;
30: : and! ( n addr -- ) dup @ rot and swap ! ;
31: : +class ( class -- ) $100 0 ?DO @+ swap
32: cur-class I + or! cell +LOOP drop ;
33: : -class ( class -- ) $100 0 ?DO @+ swap invert
34: cur-class I + and! cell +LOOP drop ;
35:
36: : char? ( addr class -- addr' flag )
37: >r count r> + c@ ;
38:
39: \ Charclass tests
40:
41: : c? ( addr class -- ) ]] char? 0= ?LEAVE [[ ; immediate
42: : -c? ( addr class -- ) ]] char? ?LEAVE [[ ; immediate
43:
44: charclass digit '0 '9 ..char
45: charclass blanks 0 bl ..char
46: \ bl +char #tab +char #cr +char #lf +char ctrl L +char
47: charclass letter 'a 'z ..char 'A 'Z ..char
48: charclass any 0 $FF ..char #lf -char
49:
50: : \d ( addr -- addr' ) ]] digit c? [[ ; immediate
51: : \s ( addr -- addr' ) ]] blanks c? [[ ; immediate
52: : .? ( addr -- addr' ) ]] any c? [[ ; immediate
53: : -\d ( addr -- addr' ) ]] digit -c? [[ ; immediate
54: : -\s ( addr -- addr' ) ]] blanks -c? [[ ; immediate
55: : ` ( -- )
56: ]] count [[ char ]] Literal <> ?LEAVE [[ ; immediate
57:
58: \ A word for string comparison
59:
60: : $= ( addr1 addr2 u -- f ) tuck compare ;
61: : ,=" ( addr u -- ) tuck ]] dup SLiteral $= ?LEAVE Literal + noop [[ ;
62: : =" ( <string>" -- ) '" parse ,=" ; immediate
63:
64: \ loop stack
65:
66: Variable loops $40 3 * cells allot
67: : 3@ ( addr -- a b c ) dup >r 2 cells + @ r> 2@ ;
68: : 3! ( a b c addr -- ) dup >r 2! r> 2 cells + ! ;
69: : loops> ( -- addr ) -3 loops +! loops @+ swap cells + 3@ ;
70: : >loops ( addr -- ) loops @+ swap cells + 3! 3 loops +! ;
71: : BEGIN, ( -- ) ]] BEGIN [[ >loops ;
72: : DONE, ( -- ) loops @ IF loops> ]] DONE [[ THEN ]] noop [[ ;
73:
74: \ variables
75:
76: Variable vars &18 cells allot
77: Variable varstack 9 cells allot
78: Variable varsmax
79: : >var ( -- addr ) vars @+ swap 2* cells +
80: vars @ varstack @+ swap cells + !
81: 1 vars +! 1 varstack +! ;
82: : var> ( -- addr ) -1 varstack +!
83: varstack @+ swap cells + @
84: 1+ 2* cells vars + ;
85:
86: \ start end
87:
88: 0 Value end$
89: 0 Value start$
90: : !end ( addr u -- addr ) over + to end$ dup to start$ ;
91: : $? ( addr -- addr flag ) dup end$ u< ;
92: : ^? ( addr -- addr flag ) dup start$ u> ;
93: : ?end ( addr -- addr ) ]] dup end$ u> ?LEAVE [[ ; immediate
94:
95: \ start and end
96:
97: : \^ ( addr -- addr )
98: ]] ^? ?LEAVE [[ ; immediate
99: : \$ ( addr -- addr )
100: ]] $? ?LEAVE [[ ; immediate
101:
102: \ regexp block
103:
104: \ FORK/JOIN are like AHEAD THEN, but producing a call on AHEAD
105: \ instead of a jump.
106:
107: : (( ( addr u -- ) vars off varsmax off loops off
108: ]] FORK AHEAD BUT JOIN !end [[ BEGIN, ; immediate
109: : )) ( -- addr f )
110: ]] ?end drop true EXIT [[
111: DONE, ]] drop false EXIT THEN [[ ; immediate
112:
113: \ greedy loops
114:
115: \ Idea: scan as many characters as possible, try the rest of the pattern
116: \ and then back off one pattern at a time
117:
118: : drops ( n -- ) 1+ cells sp@ + sp! ;
119:
120: : {** ( addr -- addr addr )
121: 0 ]] Literal >r BEGIN dup [[ BEGIN, ; immediate
122: ' {** Alias {++ ( addr -- addr addr ) immediate
123: : n*} ( sys n -- ) >r ]] r> 1+ >r $? 0= UNTIL dup [[ DONE, ]] drop [[
124: r@ IF r@ ]] r@ Literal u< IF r> 1+ drops false EXIT THEN [[ THEN
125: r@ ]] r> 1+ Literal U+DO FORK BUT [[
126: ]] IF I' I - [[ r@ 1- ]] Literal + drops true UNLOOP EXIT THEN LOOP [[
127: r@ IF r@ ]] Literal drops [[ THEN
128: rdrop ]] false EXIT JOIN [[ ; immediate
129: : **} 0 postpone n*} ; immediate
130: : ++} 1 postpone n*} ; immediate
131:
132: \ non-greedy loops
133:
134: \ Idea: Try to match rest of the regexp, and if that fails, try match
135: \ first expr and then try again rest of regexp.
136:
137: : {+ ( addr -- addr addr )
138: ]] BEGIN [[ BEGIN, ; immediate
139: : {* ( addr -- addr addr )
140: ]] {+ dup FORK BUT IF drop true EXIT THEN [[ ; immediate
141: : *} ( addr addr' -- addr' )
142: ]] dup end$ u> UNTIL [[
143: DONE, ]] drop false EXIT JOIN [[ ; immediate
144: : +} ( addr addr' -- addr' )
145: ]] dup FORK BUT IF drop true EXIT [[
146: DONE, ]] drop false EXIT THEN *} [[ ; immediate
147:
148: : // ( -- ) ]] {* 1+ *} [[ ; immediate
149:
150: \ alternatives
151:
152: \ idea: try to match one alternative and then the rest of regexp.
153: \ if that fails, jump back to second alternative
154:
155: : THENs ( sys -- ) BEGIN dup WHILE ]] THEN [[ REPEAT drop ;
156:
157: : {{ ( addr -- addr addr ) 0 ]] dup BEGIN [[ vars @ ; immediate
158: : || ( addr addr -- addr addr ) vars @ varsmax @ max varsmax !
159: ]] nip AHEAD [[ >r >r >r vars !
160: ]] DONE drop dup [[ r> r> r> ]] BEGIN [[ vars @ ; immediate
161: : }} ( addr addr -- addr addr ) vars @ varsmax @ max vars !
162: ]] nip AHEAD [[ >r >r >r drop
163: ]] DONE drop LEAVE [[ r> r> r> THENs ; immediate
164:
165: \ match variables
166:
167: : \( ( addr -- addr ) ]] dup [[
168: >var ]] ALiteral ! [[ ; immediate
169: : \) ( addr -- addr ) ]] dup [[
170: var> ]] ALiteral ! [[ ; immediate
171: : \0 ( -- addr u ) start$ end$ over - ;
172: : \: ( i -- )
173: Create 2* 1+ cells vars + ,
174: DOES> ( -- addr u ) @ 2@ tuck - ;
175: : \:s ( n -- ) 0 ?DO I \: LOOP ;
176: 9 \:s \1 \2 \3 \4 \5 \6 \7 \8 \9
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