Question

我正在尝试使用lex / yacc程序解析以下配置文件。

我的配置文件如下所示。

[ main ]
e_type=0x1B

我的lex文件如下（test.l）

%option noyywrap
%{

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
enum{
    T_E_TYPE = 1,
    T_MAIN_SECTION = 3,
    T_NUMBER = 4,
    T_EQUAL = 5,
};

/**
 * Forward declerations
 **/
void Number ();
void HexaNumber ();

%}

%option nounput
%option noinput
%option case-insensitive

/*-----------------------------------------------------------------
   Some macros (standard regular expressions)
------------------------------------------------------------------*/

HEXALETTER  [a-fA-F]
HEXANUMBER  [0][x](({DIGIT}|{HEXALETTER})+)
NUM         {DIGIT}+
HEXA        ({DIGIT}|{HEXALETTER}|[*])
STR         \"[^\"]*\"
WSPACE      [ \t]*
NEWLINE     [\n\r]        

/*----------------------------------------------------------------
   The lexer rules
------------------------------------------------------------------*/
%%

%{
    yylval = 0; /* do this for every token not using yylval, to be on the safe side */
%}
e_type                   { return T_E_TYPE; }
main                     { return T_MAIN_SECTION;}
HEXANUMBER               { HexaNumber(); return T_NUMBER; }
=                        { return T_EQUAL; }

[^\t\n\r]                { }

%%

void Number () {
    yylval.l = atol(yytext);
}

void HexaNumber () {
    //yylval.l = (unsigned int) strtol(yytext, (char **)NULL, 16);
    yylval.l = dagstrtol16 (yytext);
}

我的yacc文件如下。（test.y）

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

#ifdef E_PARSE_DEBUG
// Some yacc (bison) defines
#define YYDEBUG 1       // Generate debug code; needed for YYERROR_VERBOSE
#define YYERROR_VERBOSE // Give a more specific parse error message 
#endif

static FILE *scan_log_file = NULL;
static void debug_log_message(const char* location , const char *fmt,...);
static void found_main_section_complete(void);

void yyerror(const char *str)
{
  fprintf(stderr,"error: %s\n",str);
}

int yywrap()
{
  return 1;
}

int main()
{
  printf("> "); 
  yyparse();
  return 0;
}
%}

/*------------------------------------------------------------------
  Yacc declarations
------------------------------------------------------------------ */

/* The structure for passing value between lexer and parser */
/* In the lexer we know it by the name 'yylval'*/
%union {
   char *str;
   unsigned long l;
   void * distr;
   void * command;
}

%token T_E_TYPE 
%type <l> number

%%
config_file_sections
    : main 
    ;

main
    : main_attribute_list 
    {
        debug_log_message(E_DEBUG_AT,"Found main_section\n");
        parse_found_main_section_complete();
    }
    ;
main_attribute_list
    : T_E_TYPE number
    {
        debug_log_message(E_DEBUG_AT,"Found main section token T_E_TYPE\n");
    }
number
    : NUMBER { $$ = (unsigned long) $1; }
    ;
%%

void debug_log_message(const char* location , const char *fmt,...)                                                                                                         
{
#ifdef E_PARSE_DEBUG
  va_list ap;
  if (scan_log_file)
  {
   fprintf(scan_log_file, "At %s:(line%d) ", location, lineno);
   va_start(ap, fmt);
   (void) vfprintf(scan_log_file, fmt, ap);
   va_end(ap);
  }
#endif
  return;
}

static void parse_found_main_section_complete(void)                                                                                                                                 
{
  int i  = 0;
  dagutil_verbose_level(1,"Parsed main section rules\n");
  if (dagutil_get_verbosity() > 0 )
  {
    //:TODO
  }
  return;
}

我按如下方式编译文件。

flex test.l
yacc -d test.y
gcc lex.yy.c y.tab.c -Wall  -ll -o test

我收到以下错误

yacc: e - line 67 of "test.y", $1 (NUMBER) is untyped
test.l: In function ‘yylex’:
test.l:44:5: error: ‘yylval’ undeclared (first use in this function)
     yylval = 0; /* do this for every token not using yylval, to be on the safe side */
     ^
test.l:44:5: note: each undeclared identifier is reported only once for each function it appears in
test.l: In function ‘Number’:
test.l:57:5: error: ‘yylval’ undeclared (first use in this function)
 }
     ^
test.l: In function ‘HexaNumber’:
test.l:62:5: error: ‘yylval’ undeclared (first use in this function)
 }
     ^
test.l:62:5: warning: implicit declaration of function ‘dagstrtol16’ [-Wimplicit-function-declaration]

我不知道yylval应该在哪里声明。生成的“y.tab.h”似乎是空的

Answer 1

您的.l文件需要

#include "y.tab.h"

它应该不包含它自己的令牌声明。它们应该或者应该在y.tab.h中。

我认为还有其他问题：见评论。

Yacc错误错误：'yylval'未声明（在此函数中首次使用）

1 个答案: