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%{
#include <u.h>
#include <libc.h>
#include <ctype.h>
#include "dat.h"
char *yylp; /* next character to be lex'd */
char *yybuffer;
char *yyend; /* end of buffer to be parsed */
%}
%term LOR
%term LAND
%term WORD
%right '!'
%left '|'
%left '&'
%left LOR
%left LAND
%start filter
%%
filter : expr
{ filter = $$; }
;
expr : WORD
{ $$ = $1; }
| WORD '=' WORD
{ $2->l = $1; $2->r = $3; $$ = $2; }
| WORD '(' expr ')'
{ $1->l = $3; free($2); free($4); $$ = $1; }
| '(' expr ')'
{ free($1); free($3); $$ = $2; }
| expr LOR expr
{ $2->l = $1; $2->r = $3; $$ = $2; }
| expr LAND expr
{ $2->l = $1; $2->r = $3; $$ = $2; }
| '!' expr
{ $1->l = $2; $$ = $1; }
;
%%
/*
* Initialize the parsing. Done once for each header field.
*/
void
yyinit(char *p)
{
yylp = p;
}
int
yylex(void)
{
char *p;
int c;
if(yylp == nil || *yylp == 0)
return 0;
while(isspace(*yylp))
yylp++;
yylval = newfilter();
p = strpbrk(yylp, "!|&()= ");
if(p == 0){
yylval->op = WORD;
yylval->s = strdup(yylp);
if(yylval->s == nil)
sysfatal("parsing filter: %r");
yylp = nil;
return WORD;
}
c = *p;
if(p != yylp){
yylval->op = WORD;
*p = 0;
yylval->s = strdup(yylp);
if(yylval->s == nil)
sysfatal("parsing filter: %r");
*p = c;
yylp = p;
return WORD;
}
yylp++;
if(*yylp == c)
switch(c){
case '&':
c = LAND;
yylp++;
break;
case '|':
c = LOR;
yylp++;
break;
}
yylval->op = c;
return c;
}
void
yyerror(char *e)
{
USED(e);
sysfatal("error parsing filter");
}
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