Bison yylex的多重定义

我试过下面的lex和yacc文件，似乎有很多函数的多个定义，比如yylex、yyrestart等等。我尝试了几种方法和在线材料，但无法解决它。任何帮助都将不胜感激

try1.l文件如下所示

%{
#include "y.tab.h"
int linenum=1;
int temp_int;
%}
%%

\n     {linenum++;}

[\t ]         /* skip spaces */;
\/\/[^\n]*    /* ignore comments */;

"+"     {return '+';}
"-"     {return '-';}
"*"     {return '*';}
"/"     {return '/';}
")"     {return ')';}
"("     {return '(';}

[0-9]+   {sscanf(yytext, "%d", &temp_int);
          yylval.int_val = temp_int;
          return INT;}

.  {printf("LEX: unknown input string found in line %d \n", linenum);
    abort();}
%%

int yywrap(void) {return 1;}

/* Put new code here */

%{
#include <stdio.h>
#include <ctype.h>


extern int linenum;
%}


/* define all types of variables and terminals */  

%union{
  int int_val;
}

/* define the individual types of variables and terminals */

%token <int_val> INT   
%type <int_val> expr



/* assign priorities to operators in order to 
   avoid shift/reduce conflicts (grammar ambiguities) */

%left '+' '-'
%left '*' '/'
%left UMINUS


/* the start variable of your program */

%start program


/* The main Grammar with its actions */

%%

program : expr        {printf("Expr value = %d \n", $1);}
        | error       {printf("YACC: syntax error near line %d \n", linenum);
                       abort();}
        ;

expr :'('expr')'        {$$ = $2;}  
     | expr '+' expr    {$$ = $1 + $3;}
     | expr '-' expr    {$$ = $1 - $3;}
     | expr  '*' expr   {$$ = $1 * $3;}
     | expr '/' expr    {$$ = $1 / $3;}
     | '-' expr  %prec UMINUS  {$$ = -$2;}
     | INT              {$$ = $1;}
     ;
      

%%

/* link lex code */

#include "lex.yy.c"

/* insert additional code here */

int main(){
    return yyparse();
}

int yyerror(char *s) {fprintf(stderr, "%s \n",s);}

try1.y文件如下所示

%{
#include "y.tab.h"
int linenum=1;
int temp_int;
%}
%%

\n     {linenum++;}

[\t ]         /* skip spaces */;
\/\/[^\n]*    /* ignore comments */;

"+"     {return '+';}
"-"     {return '-';}
"*"     {return '*';}
"/"     {return '/';}
")"     {return ')';}
"("     {return '(';}

[0-9]+   {sscanf(yytext, "%d", &temp_int);
          yylval.int_val = temp_int;
          return INT;}

.  {printf("LEX: unknown input string found in line %d \n", linenum);
    abort();}
%%

int yywrap(void) {return 1;}

/* Put new code here */

%{
#include <stdio.h>
#include <ctype.h>


extern int linenum;
%}


/* define all types of variables and terminals */  

%union{
  int int_val;
}

/* define the individual types of variables and terminals */

%token <int_val> INT   
%type <int_val> expr



/* assign priorities to operators in order to 
   avoid shift/reduce conflicts (grammar ambiguities) */

%left '+' '-'
%left '*' '/'
%left UMINUS


/* the start variable of your program */

%start program


/* The main Grammar with its actions */

%%

program : expr        {printf("Expr value = %d \n", $1);}
        | error       {printf("YACC: syntax error near line %d \n", linenum);
                       abort();}
        ;

expr :'('expr')'        {$$ = $2;}  
     | expr '+' expr    {$$ = $1 + $3;}
     | expr '-' expr    {$$ = $1 - $3;}
     | expr  '*' expr   {$$ = $1 * $3;}
     | expr '/' expr    {$$ = $1 / $3;}
     | '-' expr  %prec UMINUS  {$$ = -$2;}
     | INT              {$$ = $1;}
     ;
      

%%

/* link lex code */

#include "lex.yy.c"

/* insert additional code here */

int main(){
    return yyparse();
}

int yyerror(char *s) {fprintf(stderr, "%s \n",s);}

/*在此处放置新代码*/
%{
#包括
#包括
外部内部行数；
%}
/*定义所有类型的变量和端子*/
%联合{
国际价值；
}
/*定义变量和端子的各个类型*/
%标记整数
%类型表达式
/*为操作员分配优先级，以便
避免移位/减少冲突（语法歧义）*/
%左'+''-'
%左'*''/'
%左耳门
/*程序的开始变量*/
%启动程序
/*主语法及其动作*/
%%
程序：expr{printf（“expr值=%d\n”，$1）；}
|错误{printf（“YACC:第%d行附近的语法错误”，linenum）；
中止（）；}
;
expr:“（'expr'）”{$$=$2；}
|expr'+'expr{$$=$1+$3；}
|expr'-'expr{$$=$1-$3；}
|expr'*'expr{$$=$1*$3；}
|expr'/'expr{$$=$1/$3；}
|“-”表达式%prec-UMINUS{$$=-$2；}
|INT{$$=$1；}
;
%%
/*链接法代码*/
#包括“lex.yy.c”
/*在此处插入其他代码*/
int main（）{
返回yyparse（）；
}
int yyerror（char*s）{fprintf（stderr，“%s\n”，s）；}

输出如下：

%{
#include "y.tab.h"
int linenum=1;
int temp_int;
%}
%%

\n     {linenum++;}

[\t ]         /* skip spaces */;
\/\/[^\n]*    /* ignore comments */;

"+"     {return '+';}
"-"     {return '-';}
"*"     {return '*';}
"/"     {return '/';}
")"     {return ')';}
"("     {return '(';}

[0-9]+   {sscanf(yytext, "%d", &temp_int);
          yylval.int_val = temp_int;
          return INT;}

.  {printf("LEX: unknown input string found in line %d \n", linenum);
    abort();}
%%

int yywrap(void) {return 1;}

/* Put new code here */

%{
#include <stdio.h>
#include <ctype.h>


extern int linenum;
%}


/* define all types of variables and terminals */  

%union{
  int int_val;
}

/* define the individual types of variables and terminals */

%token <int_val> INT   
%type <int_val> expr



/* assign priorities to operators in order to 
   avoid shift/reduce conflicts (grammar ambiguities) */

%left '+' '-'
%left '*' '/'
%left UMINUS


/* the start variable of your program */

%start program


/* The main Grammar with its actions */

%%

program : expr        {printf("Expr value = %d \n", $1);}
        | error       {printf("YACC: syntax error near line %d \n", linenum);
                       abort();}
        ;

expr :'('expr')'        {$$ = $2;}  
     | expr '+' expr    {$$ = $1 + $3;}
     | expr '-' expr    {$$ = $1 - $3;}
     | expr  '*' expr   {$$ = $1 * $3;}
     | expr '/' expr    {$$ = $1 / $3;}
     | '-' expr  %prec UMINUS  {$$ = -$2;}
     | INT              {$$ = $1;}
     ;
      

%%

/* link lex code */

#include "lex.yy.c"

/* insert additional code here */

int main(){
    return yyparse();
}

int yyerror(char *s) {fprintf(stderr, "%s \n",s);}

---

您看到这个问题是因为词法分析器的源代码包含了两次

当同时使用lex和yacc（或flex和bison）时，生成的编译器（yacc输出）通常包含生成的词法分析器源

您可以在

try1.y

和输出

try1.tab.c

代码中看到这一点：

/* link lex code */

#include "lex.yy.c"

/* insert additional code here */

因此，要么从

try1.tab.c

中手动删除它，要么不要将

lex.yy.c

与

try1.tab.c

一起编译

可能只是：

$ flex try1.l
$ bison -d try1.y
$ gcc -g -Wall try1.tab.c -o try1.exe

---

将帮助您继续。

请不要发布错误日志的屏幕截图，它们是不可搜索的。当然，谢谢您提供的信息。