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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 %}
     33 
     34 %locations
     35 
     36 %union {
     37     char* str;
     38     Expr* expr;
     39     struct {
     40         int argc;
     41         Expr** argv;
     42     } args;
     43 }
     44 
     45 %token AND OR SUBSTR SUPERSTR EQ NE IF THEN ELSE ENDIF
     46 %token <str> STRING BAD
     47 %type <expr> expr
     48 %type <args> arglist
     49 
     50 %parse-param {Expr** root}
     51 %parse-param {int* error_count}
     52 %error-verbose
     53 
     54 /* declarations in increasing order of precedence */
     55 %left ';'
     56 %left ','
     57 %left OR
     58 %left AND
     59 %left EQ NE
     60 %left '+'
     61 %right '!'
     62 
     63 %%
     64 
     65 input:  expr           { *root = $1; }
     66 ;
     67 
     68 expr:  STRING {
     69     $$ = malloc(sizeof(Expr));
     70     $$->fn = Literal;
     71     $$->name = $1;
     72     $$->argc = 0;
     73     $$->argv = NULL;
     74     $$->start = @$.start;
     75     $$->end = @$.end;
     76 }
     77 |  '(' expr ')'                      { $$ = $2; $$->start=@$.start; $$->end=@$.end; }
     78 |  expr ';'                          { $$ = $1; $$->start=@1.start; $$->end=@1.end; }
     79 |  expr ';' expr                     { $$ = Build(SequenceFn, @$, 2, $1, $3); }
     80 |  error ';' expr                    { $$ = $3; $$->start=@$.start; $$->end=@$.end; }
     81 |  expr '+' expr                     { $$ = Build(ConcatFn, @$, 2, $1, $3); }
     82 |  expr EQ expr                      { $$ = Build(EqualityFn, @$, 2, $1, $3); }
     83 |  expr NE expr                      { $$ = Build(InequalityFn, @$, 2, $1, $3); }
     84 |  expr AND expr                     { $$ = Build(LogicalAndFn, @$, 2, $1, $3); }
     85 |  expr OR expr                      { $$ = Build(LogicalOrFn, @$, 2, $1, $3); }
     86 |  '!' expr                          { $$ = Build(LogicalNotFn, @$, 1, $2); }
     87 |  IF expr THEN expr ENDIF           { $$ = Build(IfElseFn, @$, 2, $2, $4); }
     88 |  IF expr THEN expr ELSE expr ENDIF { $$ = Build(IfElseFn, @$, 3, $2, $4, $6); }
     89 | STRING '(' arglist ')' {
     90     $$ = malloc(sizeof(Expr));
     91     $$->fn = FindFunction($1);
     92     if ($$->fn == NULL) {
     93         char buffer[256];
     94         snprintf(buffer, sizeof(buffer), "unknown function \"%s\"", $1);
     95         yyerror(root, error_count, buffer);
     96         YYERROR;
     97     }
     98     $$->name = $1;
     99     $$->argc = $3.argc;
    100     $$->argv = $3.argv;
    101     $$->start = @$.start;
    102     $$->end = @$.end;
    103 }
    104 ;
    105 
    106 arglist:    /* empty */ {
    107     $$.argc = 0;
    108     $$.argv = NULL;
    109 }
    110 | expr {
    111     $$.argc = 1;
    112     $$.argv = malloc(sizeof(Expr*));
    113     $$.argv[0] = $1;
    114 }
    115 | arglist ',' expr {
    116     $$.argc = $1.argc + 1;
    117     $$.argv = realloc($$.argv, $$.argc * sizeof(Expr*));
    118     $$.argv[$$.argc-1] = $3;
    119 }
    120 ;
    121 
    122 %%
    123 
    124 void yyerror(Expr** root, int* error_count, const char* s) {
    125   if (strlen(s) == 0) {
    126     s = "syntax error";
    127   }
    128   printf("line %d col %d: %s\n", gLine, gColumn, s);
    129   ++*error_count;
    130 }
    131