GopherProxy

	grep.y - 9base - revived minimalist port of Plan 9 userland to Unix
	git clone git://git.suckless.org/9base
	Log
	Files
	Refs
	README
	LICENSE
	---
	grep.y (2815B)
	---
	1 %{
	2 #include "grep.h"
	3 %}
	4
	5 %union
	6 {
	7 int val;
	8 char* str;
	9 Re2 re;
	10 }
	11
	12 %type <re> expr prog
	13 %type <re> expr0 expr1 expr2 expr3 expr4
	14 %token <str> LCLASS
	15 %token <val> LCHAR
	16 %token LLPAREN LRPAREN LALT LSTAR LPLUS LQUES
	17 %token LBEGIN LEND LDOT LBAD LNEWLINE
	18 %%
	19
	20 prog:
	21 expr newlines
	22 {
	23 $$.beg = ral(Tend);
	24 $$.end = $$.beg;
	25 $$ = re2cat(re2star(re2or(re2char(0x00, '\n'-1), re2char…
	26 $$ = re2cat($1, $$);
	27 $$ = re2cat(re2star(re2char(0x00, 0xff)), $$);
	28 topre = $$;
	29 }
	30
	31 expr:
	32 expr0
	33 \| expr newlines expr0
	34 {
	35 $$ = re2or($1, $3);
	36 }
	37
	38 expr0:
	39 expr1
	40 \| LSTAR { literal = 1; } expr1
	41 {
	42 $$ = $3;
	43 }
	44
	45 expr1:
	46 expr2
	47 \| expr1 LALT expr2
	48 {
	49 $$ = re2or($1, $3);
	50 }
	51
	52 expr2:
	53 expr3
	54 \| expr2 expr3
	55 {
	56 $$ = re2cat($1, $2);
	57 }
	58
	59 expr3:
	60 expr4
	61 \| expr3 LSTAR
	62 {
	63 $$ = re2star($1);
	64 }
	65 \| expr3 LPLUS
	66 {
	67 $$.beg = ral(Talt);
	68 patchnext($1.end, $$.beg);
	69 $$.beg->u.alt = $1.beg;
	70 $$.end = $$.beg;
	71 $$.beg = $1.beg;
	72 }
	73 \| expr3 LQUES
	74 {
	75 $$.beg = ral(Talt);
	76 $$.beg->u.alt = $1.beg;
	77 $$.end = $1.end;
	78 appendnext($$.end, $$.beg);
	79 }
	80
	81 expr4:
	82 LCHAR
	83 {
	84 $$.beg = ral(Tclass);
	85 $$.beg->u.x.lo = $1;
	86 $$.beg->u.x.hi = $1;
	87 $$.end = $$.beg;
	88 }
	89 \| LBEGIN
	90 {
	91 $$.beg = ral(Tbegin);
	92 $$.end = $$.beg;
	93 }
	94 \| LEND
	95 {
	96 $$.beg = ral(Tend);
	97 $$.end = $$.beg;
	98 }
	99 \| LDOT
	100 {
	101 $$ = re2class("^\n");
	102 }
	103 \| LCLASS
	104 {
	105 $$ = re2class($1);
	106 }
	107 \| LLPAREN expr1 LRPAREN
	108 {
	109 $$ = $2;
	110 }
	111
	112 newlines:
	113 LNEWLINE
	114 \| newlines LNEWLINE
	115 %%
	116
	117 void
	118 yyerror(char *e, ...)
	119 {
	120 if(filename)
	121 fprint(2, "grep: %s:%ld: %s\n", filename, lineno, e);
	122 else
	123 fprint(2, "grep: %s\n", e);
	124 exits("syntax");
	125 }
	126
	127 int
	128 yylex(void)
	129 {
	130 char q, eq;
	131 int c, s;
	132
	133 if(peekc) {
	134 s = peekc;
	135 peekc = 0;
	136 return s;
	137 }
	138 c = getrec();
	139 if(literal) {
	140 if(c != 0 && c != '\n') {
	141 yylval.val = c;
	142 return LCHAR;
	143 }
	144 literal = 0;
	145 }
	146 switch(c) {
	147 default:
	148 yylval.val = c;
	149 s = LCHAR;
	150 break;
	151 case '\\':
	152 c = getrec();
	153 yylval.val = c;
	154 s = LCHAR;
	155 if(c == '\n')
	156 s = LNEWLINE;
	157 break;
	158 case '[':
	159 goto getclass;
	160 case '(':
	161 s = LLPAREN;
	162 break;
	163 case ')':
	164 s = LRPAREN;
	165 break;
	166 case '\|':
	167 s = LALT;
	168 break;
	169 case '*':
	170 s = LSTAR;
	171 break;
	172 case '+':
	173 s = LPLUS;
	174 break;
	175 case '?':
	176 s = LQUES;
	177 break;
	178 case '^':
	179 s = LBEGIN;
	180 break;
	181 case '$':
	182 s = LEND;
	183 break;
	184 case '.':
	185 s = LDOT;
	186 break;
	187 case 0:
	188 peekc = -1;
	189 case '\n':
	190 s = LNEWLINE;
	191 break;
	192 }
	193 return s;
	194
	195 getclass:
	196 q = u.string;
	197 eq = q + nelem(u.string) - 5;
	198 c = getrec();
	199 if(c == '^') {
	200 q[0] = '^';
	201 q[1] = '\n';
	202 q[2] = '-';
	203 q[3] = '\n';
	204 q += 4;
	205 c = getrec();
	206 }
	207 for(;;) {
	208 if(q >= eq)
	209 error("class too long");
	210 if(c == ']' \|\| c == 0)
	211 break;
	212 if(c == '\\') {
	213 *q++ = c;
	214 c = getrec();
	215 if(c == 0)
	216 break;
	217 }
	218 *q++ = c;
	219 c = getrec();
	220 }
	221 *q = 0;
	222 if(c == 0)
	223 return LBAD;
	224 yylval.str = u.string;
	225 return LCLASS;
	226 }