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      1 %{
      2 /*
      3  * Copyright (C) 2009 The Android Open Source Project
      4  *
      5  * Licensed under the Apache License, Version 2.0 (the "License");
      6  * you may not use this file except in compliance with the License.
      7  * You may obtain a copy of the License at
      8  *
      9  *      http://www.apache.org/licenses/LICENSE-2.0
     10  *
     11  * Unless required by applicable law or agreed to in writing, software
     12  * distributed under the License is distributed on an "AS IS" BASIS,
     13  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     14  * See the License for the specific language governing permissions and
     15  * limitations under the License.
     16  */
     17 
     18 #include <stdio.h>
     19 #include <stdlib.h>
     20 #include <string.h>
     21 
     22 #include "expr.h"
     23 #include "yydefs.h"
     24 #include "parser.h"
     25 
     26 extern int gLine;
     27 extern int gColumn;
     28 
     29 void yyerror(Expr** root, int* error_count, const char* s);
     30 int yyparse(Expr** root, int* error_count);
     31 
     32 struct yy_buffer_state;
     33 void yy_switch_to_buffer(struct yy_buffer_state* new_buffer);
     34 struct yy_buffer_state* yy_scan_string(const char* yystr);
     35 
     36 %}
     37 
     38 %locations
     39 
     40 %union {
     41     char* str;
     42     Expr* expr;
     43     struct {
     44         int argc;
     45         Expr** argv;
     46     } args;
     47 }
     48 
     49 %token AND OR SUBSTR SUPERSTR EQ NE IF THEN ELSE ENDIF
     50 %token <str> STRING BAD
     51 %type <expr> expr
     52 %type <args> arglist
     53 
     54 %parse-param {Expr** root}
     55 %parse-param {int* error_count}
     56 %error-verbose
     57 
     58 /* declarations in increasing order of precedence */
     59 %left ';'
     60 %left ','
     61 %left OR
     62 %left AND
     63 %left EQ NE
     64 %left '+'
     65 %right '!'
     66 
     67 %%
     68 
     69 input:  expr           { *root = $1; }
     70 ;
     71 
     72 expr:  STRING {
     73     $$ = malloc(sizeof(Expr));
     74     $$->fn = Literal;
     75     $$->name = $1;
     76     $$->argc = 0;
     77     $$->argv = NULL;
     78     $$->start = @$.start;
     79     $$->end = @$.end;
     80 }
     81 |  '(' expr ')'                      { $$ = $2; $$->start=@$.start; $$->end=@$.end; }
     82 |  expr ';'                          { $$ = $1; $$->start=@1.start; $$->end=@1.end; }
     83 |  expr ';' expr                     { $$ = Build(SequenceFn, @$, 2, $1, $3); }
     84 |  error ';' expr                    { $$ = $3; $$->start=@$.start; $$->end=@$.end; }
     85 |  expr '+' expr                     { $$ = Build(ConcatFn, @$, 2, $1, $3); }
     86 |  expr EQ expr                      { $$ = Build(EqualityFn, @$, 2, $1, $3); }
     87 |  expr NE expr                      { $$ = Build(InequalityFn, @$, 2, $1, $3); }
     88 |  expr AND expr                     { $$ = Build(LogicalAndFn, @$, 2, $1, $3); }
     89 |  expr OR expr                      { $$ = Build(LogicalOrFn, @$, 2, $1, $3); }
     90 |  '!' expr                          { $$ = Build(LogicalNotFn, @$, 1, $2); }
     91 |  IF expr THEN expr ENDIF           { $$ = Build(IfElseFn, @$, 2, $2, $4); }
     92 |  IF expr THEN expr ELSE expr ENDIF { $$ = Build(IfElseFn, @$, 3, $2, $4, $6); }
     93 | STRING '(' arglist ')' {
     94     $$ = malloc(sizeof(Expr));
     95     $$->fn = FindFunction($1);
     96     if ($$->fn == NULL) {
     97         char buffer[256];
     98         snprintf(buffer, sizeof(buffer), "unknown function \"%s\"", $1);
     99         yyerror(root, error_count, buffer);
    100         YYERROR;
    101     }
    102     $$->name = $1;
    103     $$->argc = $3.argc;
    104     $$->argv = $3.argv;
    105     $$->start = @$.start;
    106     $$->end = @$.end;
    107 }
    108 ;
    109 
    110 arglist:    /* empty */ {
    111     $$.argc = 0;
    112     $$.argv = NULL;
    113 }
    114 | expr {
    115     $$.argc = 1;
    116     $$.argv = malloc(sizeof(Expr*));
    117     $$.argv[0] = $1;
    118 }
    119 | arglist ',' expr {
    120     $$.argc = $1.argc + 1;
    121     $$.argv = realloc($$.argv, $$.argc * sizeof(Expr*));
    122     $$.argv[$$.argc-1] = $3;
    123 }
    124 ;
    125 
    126 %%
    127 
    128 void yyerror(Expr** root, int* error_count, const char* s) {
    129   if (strlen(s) == 0) {
    130     s = "syntax error";
    131   }
    132   printf("line %d col %d: %s\n", gLine, gColumn, s);
    133   ++*error_count;
    134 }
    135 
    136 int parse_string(const char* str, Expr** root, int* error_count) {
    137     yy_switch_to_buffer(yy_scan_string(str));
    138     return yyparse(root, error_count);
    139 }
    140