%{
/*
* Copyright (C) 2009 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "expr.h"
#include "yydefs.h"
#include "parser.h"
extern int gLine;
extern int gColumn;
void yyerror(Expr** root, int* error_count, const char* s);
int yyparse(Expr** root, int* error_count);
struct yy_buffer_state;
void yy_switch_to_buffer(struct yy_buffer_state* new_buffer);
struct yy_buffer_state* yy_scan_string(const char* yystr);
// Convenience function for building expressions with a fixed number
// of arguments.
static Expr* Build(Function fn, YYLTYPE loc, size_t count, ...) {
va_list v;
va_start(v, count);
Expr* e = static_cast<Expr*>(malloc(sizeof(Expr)));
e->fn = fn;
e->name = "(operator)";
e->argc = count;
e->argv = static_cast<Expr**>(malloc(count * sizeof(Expr*)));
for (size_t i = 0; i < count; ++i) {
e->argv[i] = va_arg(v, Expr*);
}
va_end(v);
e->start = loc.start;
e->end = loc.end;
return e;
}
%}
%locations
%union {
char* str;
Expr* expr;
struct {
int argc;
Expr** argv;
} args;
}
%token AND OR SUBSTR SUPERSTR EQ NE IF THEN ELSE ENDIF
%token <str> STRING BAD
%type <expr> expr
%type <args> arglist
%parse-param {Expr** root}
%parse-param {int* error_count}
%error-verbose
/* declarations in increasing order of precedence */
%left ';'
%left ','
%left OR
%left AND
%left EQ NE
%left '+'
%right '!'
%%
input: expr { *root = $1; }
;
expr: STRING {
$$ = static_cast<Expr*>(malloc(sizeof(Expr)));
$$->fn = Literal;
$$->name = $1;
$$->argc = 0;
$$->argv = NULL;
$$->start = @$.start;
$$->end = @$.end;
}
| '(' expr ')' { $$ = $2; $$->start=@$.start; $$->end=@$.end; }
| expr ';' { $$ = $1; $$->start=@1.start; $$->end=@1.end; }
| expr ';' expr { $$ = Build(SequenceFn, @$, 2, $1, $3); }
| error ';' expr { $$ = $3; $$->start=@$.start; $$->end=@$.end; }
| expr '+' expr { $$ = Build(ConcatFn, @$, 2, $1, $3); }
| expr EQ expr { $$ = Build(EqualityFn, @$, 2, $1, $3); }
| expr NE expr { $$ = Build(InequalityFn, @$, 2, $1, $3); }
| expr AND expr { $$ = Build(LogicalAndFn, @$, 2, $1, $3); }
| expr OR expr { $$ = Build(LogicalOrFn, @$, 2, $1, $3); }
| '!' expr { $$ = Build(LogicalNotFn, @$, 1, $2); }
| IF expr THEN expr ENDIF { $$ = Build(IfElseFn, @$, 2, $2, $4); }
| IF expr THEN expr ELSE expr ENDIF { $$ = Build(IfElseFn, @$, 3, $2, $4, $6); }
| STRING '(' arglist ')' {
$$ = static_cast<Expr*>(malloc(sizeof(Expr)));
$$->fn = FindFunction($1);
if ($$->fn == nullptr) {
char buffer[256];
snprintf(buffer, sizeof(buffer), "unknown function \"%s\"", $1);
yyerror(root, error_count, buffer);
YYERROR;
}
$$->name = $1;
$$->argc = $3.argc;
$$->argv = $3.argv;
$$->start = @$.start;
$$->end = @$.end;
}
;
arglist: /* empty */ {
$$.argc = 0;
$$.argv = NULL;
}
| expr {
$$.argc = 1;
$$.argv = static_cast<Expr**>(malloc(sizeof(Expr*)));
$$.argv[0] = $1;
}
| arglist ',' expr {
$$.argc = $1.argc + 1;
$$.argv = static_cast<Expr**>(realloc($$.argv, $$.argc * sizeof(Expr*)));
$$.argv[$$.argc-1] = $3;
}
;
%%
void yyerror(Expr** root, int* error_count, const char* s) {
if (strlen(s) == 0) {
s = "syntax error";
}
printf("line %d col %d: %s\n", gLine, gColumn, s);
++*error_count;
}
int parse_string(const char* str, Expr** root, int* error_count) {
yy_switch_to_buffer(yy_scan_string(str));
return yyparse(root, error_count);
}
