1 %{
2 #include <u.h>
3 #include <libc.h>
4 #include <ctype.h>
5 #include "dat.h"
6 
7 char	*yylp;		/* next character to be lex'd */
8 char	*yybuffer;
9 char	*yyend;		/* end of buffer to be parsed */
10 %}
11 
12 %term LOR
13 %term LAND
14 %term WORD
15 %term NE
16 %right '!'
17 %left '|'
18 %left '&'
19 %left LOR
20 %left LAND
21 %start filter
22 %%
23 
24 filter		: expr
25 			{ filter = $$; }
26 		;
27 expr		: WORD
28 			{ $$ = $1; }
29 		| WORD '=' WORD
30 			{ $2->l = $1; $2->r = $3; $$ = $2; }
31 		| WORD NE WORD
32 			{ $2->l = newfilter();
33 			  $2->l->op = '=';
34 			  $2->l->l = $1;
35 			  $2->l->r = $3;
36 			  $2->op = '!';
37 			  $$ = $2;
38 			}
39 		| WORD '(' expr ')'
40 			{ $1->l = $3; free($2); free($4); $$ = $1; }
41 		| '(' expr ')'
42 			{ free($1); free($3); $$ = $2; }
43 		| expr LOR expr
44 			{ $2->l = $1; $2->r = $3; $$ = $2; }
45 		| expr LAND expr
46 			{ $2->l = $1; $2->r = $3; $$ = $2; }
47 		| '!' expr
48 			{ $1->l = $2; $$ = $1; }
49 		;
50 %%
51 
52 /*
53  *  Initialize the parsing.  Done once for each header field.
54  */
55 void
56 yyinit(char *p)
57 {
58 	yylp = p;
59 }
60 
61 int
yylex(void)62 yylex(void)
63 {
64 	char *p;
65 	int c;
66 
67 	if(yylp == nil || *yylp == 0)
68 		return 0;
69 	while(isspace(*yylp))
70 		yylp++;
71 
72 	yylval = newfilter();
73 
74 	p = strpbrk(yylp, "!|&()= ");
75 	if(p == 0){
76 		yylval->op = WORD;
77 		yylval->s = strdup(yylp);
78 		if(yylval->s == nil)
79 			sysfatal("parsing filter: %r");
80 		yylp = nil;
81 		return WORD;
82 	}
83 	c = *p;
84 	if(p != yylp){
85 		yylval->op = WORD;
86 		*p = 0;
87 		yylval->s = strdup(yylp);
88 		if(yylval->s == nil)
89 			sysfatal("parsing filter: %r");
90 		*p = c;
91 		yylp = p;
92 		return WORD;
93 	}
94 
95 	yylp++;
96 	if(c == '!' && *yylp == '='){
97 		c = NE;
98 		yylp++;
99 	}
100 	else if(c == '&' && *yylp == '&'){
101 		c = LAND;
102 		yylp++;
103 	}
104 	else if(c == '|' && *yylp == '|'){
105 		c = LOR;
106 		yylp++;
107 	}
108 	yylval->op = c;
109 	return c;
110 }
111 
112 void
yyerror(char * e)113 yyerror(char *e)
114 {
115 	USED(e);
116 //	longjmp(errjmp, 1);
117 	sysfatal("error parsing filter");
118 }
119