这个 yacc 文件有什么问题？
我在以下代码中收到此错误 tema4.y:13.19-26: 语法错误，意外的类型，请帮助我！
%{
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
%}
%union {
int intval;
char* strval;
char* charval;
}
%token <charval>SHR <intval>NR
%token CMP
%type <strval>str <intval>expr
%nonassoc CMP '|'
%left '+' '-'
%left '*' '`' '#'
%start s
%%
s:str {printf("%s \n",$<strval>$);}
| expr {printf("%s \n",$<intval>$)}
;
str : str '+' str {
char* s=malloc(strlen($1)+strlen($3)+1);
strcpy(s,$1);
strcat(s,$3);
$$=s;
}
| str '-' str {
char *s=malloc(strlen($1));
char *sir=malloc(strlen($1)-strlen($3));
char *pt,*ps;
int i;
strcpy(s,$1);
pt=strstr(s,$3);
if(pt) {
ps=pt+strlen($3);
strncpy(pt,ps,strlen(ps));
ps+=strlen(ps);
strncpy(sir,s,strlen($1)-strlen($3));
}
$$=sir;
}
| str '*' NR {
int i;
char* s=malloc(strlen($1)*NR+1);
for(i=0;i<$3;i++)
{
strcat(s,$1);
}
$$=s;
}
| str '#' NR {
char *s=malloc($3+1);
strcpy(s,$1);
if($3>strlen($1)) {printf("Nr prea mare\n");exit(1);}
else {s=s+strlen(s)-$3;
$$=s;}
}
| NR '`' str {
char *s=malloc($1+1);
strncpy(s,$3,$1);
$$=s;
}
| '(' str ')' {
$$=$2;
}
| SHR {
char* s=malloc(strlen($1));
strcpy(s,$1);
$$=s;
}
| expr
;
expr : str CMP str {
if(strcmp($1,$3)) $$=0;
else $$=1;
}
| '|' str '|' {
$$=strlen($2);
}
;
%%
int main(){
yyparse();
}
I'm getting this error tema4.y:13.19-26: syntax error, unexpected typetype on the following code, please help me!
%{
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
%}
%union {
int intval;
char* strval;
char* charval;
}
%token <charval>SHR <intval>NR
%token CMP
%type <strval>str <intval>expr
%nonassoc CMP '|'
%left '+' '-'
%left '*' '`' '#'
%start s
%%
s:str {printf("%s \n",lt;strval>$);}
| expr {printf("%s \n",lt;intval>$)}
;
str : str '+' str {
char* s=malloc(strlen($1)+strlen($3)+1);
strcpy(s,$1);
strcat(s,$3);
$=s;
}
| str '-' str {
char *s=malloc(strlen($1));
char *sir=malloc(strlen($1)-strlen($3));
char *pt,*ps;
int i;
strcpy(s,$1);
pt=strstr(s,$3);
if(pt) {
ps=pt+strlen($3);
strncpy(pt,ps,strlen(ps));
ps+=strlen(ps);
strncpy(sir,s,strlen($1)-strlen($3));
}
$=sir;
}
| str '*' NR {
int i;
char* s=malloc(strlen($1)*NR+1);
for(i=0;i<$3;i++)
{
strcat(s,$1);
}
$=s;
}
| str '#' NR {
char *s=malloc($3+1);
strcpy(s,$1);
if($3>strlen($1)) {printf("Nr prea mare\n");exit(1);}
else {s=s+strlen(s)-$3;
$=s;}
}
| NR '`' str {
char *s=malloc($1+1);
strncpy(s,$3,$1);
$=s;
}
| '(' str ')' {
$=$2;
}
| SHR {
char* s=malloc(strlen($1));
strcpy(s,$1);
$=s;
}
| expr
;
expr : str CMP str {
if(strcmp($1,$3)) $=0;
else $=1;
}
| '|' str '|' {
$=strlen($2);
}
;
%%
int main(){
yyparse();
}
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评论（2）
John 已经找到了您的第一个错误的答案 -
%type或%token声明中只有一种类型。对于第二个错误（类型冲突），问题在于您的规则str: expr ;-- str 是< intval>，因此默认操作（{ $$ = $1; }实际上）存在类型冲突。您还存在某个地方的归约/归约冲突 - 您需要使用 -d 运行 yacc 并查看生成的 y.output 文件以获取有关冲突的更多详细信息。
John has the answer for your first error -- only one type in a
%typeor%tokendeclaration. For the second error (type clash), the problem is your rulestr: expr ;-- str is a<strval>while expr is an<intval>, so the default action ({ $$ = $1; }effectively) has a type clash.You also have a reduce/reduce conflict somewhere -- you'll need to run yacc with -d and look at the resulting y.output file for more detail on what the conflict is.
据我所知，
%token或%type声明中只能有一个As best I can tell you can only have one
<type>in a%tokenor%typedeclaration. You can have multiple tokens or non-terminals but only one type name. Try splitting those lines: