生成可重入解析器时出错

Errors in making a re-entrant parser

本文关键字:出错      更新时间:2023-10-16

我试了很多次,但都弄不清错误是什么。任何关于这方面的详细解释都将非常有帮助。

因此,基本上我正在尝试编写一个可重入解析器,这些是我的文件。

Lex1.ll

%{
#include "Globals.h"
#include "yac1.tab.hh"
    extern "C"
    {
        int yylex(void);
    }

%}
alpha [A-Za-z]
digit [0-9]
%option case-insensitive
%option bison-bridge
%option reentrant
%option noyywrap
%%

"DELETE ALL" return DELALL;
"INSERT"       return INSERT;

DELETE       return DELETE;
FIND         return FIND;
(+|-)?[0-9]+         { return INT;    }
n             { return ENDL; }
.    ;
%%

yac1.yy

%{
#include <stdio.h>
#include "Globals.h"
%}
%pure-parser
%error-verbose
%{
#define YYPARSE_PARAM parm
#define YYLEX_PARAM ((struct parsed_vals *)parm)->scanner
#define cast ((struct parsed_vals *) parm)
void yyerror(struct parsed_vals * parm,const char *s)
{
    fprintf(stderr, "error: %sn", s);
}
extern "C"
{
        int yylex(void );  
      //  int yywrap()
      //  {
      //          return 1;
      //  }
}
%}
%token INSERT DELETE DELALL FIND ENDL
%union {
    int ival;
    float fval;
    char *sval;
}
%token <ival> INT
%token <fval> FLOAT
%token <sval> STRING
%%
S:T    
T:      INSERT val  {cast->cmd=INSERT_CMD;}
      | DELETE val  {cast->cmd=DELETE_CMD;}
;
val :   INT ENDL    {cast->type=INT_TYPE;
                (cast->data).int_data=$1;}   
      |
        FLOAT ENDL  {cast->type=FLOAT_TYPE;
            (cast->data).float_data=$1;}  
      |
        STRING ENDL {cast->type=STRING_TYPE;
            (cast->data).str_data=$1;}       
;
%%

我的主要功能testlex.cc

#include <stdio.h>
#include "Globals.h"
#include "lexheader.h"
#include "yac1.tab.hh"
int yyparse(void *);
yyscan_t scanner;
main()
{
struct parsed_vals foo;
const char * buffer = "inseRt 4n";
yylex_init(&(foo.scanner));
yyset_extra(&foo, foo.scanner);
YY_BUFFER_STATE bp = yy_scan_string( buffer, foo.scanner ); 
yy_switch_to_buffer(bp, foo.scanner);
int a; 
int ret_val = yyparse(&foo); 
yy_delete_buffer(bp, foo.scanner);  
if(ret_val!=0) printf("False");
printf ("hello %dn",foo.data.int_data);
printf ("hello %dn",foo.type);
yylex_destroy(foo.scanner);
}

Globals.h

/* 
 * File:   Globals.h
 * Author: atghosh
 *
 * Created on 3 August, 2013, 8:39 PM
 */
#ifndef GLOBALS_H
#define GLOBALS_H
enum CMD {INSERT_CMD=1, DELETE_CMD, FIND_CMD, DELALL_CMD};
enum TYPE {INT_TYPE=5, FLOAT_TYPE, STRING_TYPE};
struct parsed_vals{
    int cmd;
    int type;
    union{      
        int int_data;
        float float_data;
        char *str_data;
    } data;
    void * scanner;
};
#endif  /* GLOBALS_H */

Makefile

parser: lex1.ll yac1.yy testlex.cc
    bison -d yac1.yy
    flex --header-file="lexheader.h" lex1.ll
    g++ -o parser yac1.tab.cc lex.yy.c testlex.cc -lfl
clean:
    rm -rf *.o parser lexheader.h  lex.yy.c  lex.yy.cc  parser   yac1.tab.cc  yac1.tab.hh 

我的错误列表

bison -d yac1.yy
flex --header-file="lexheader.h" lex1.ll
g++ -o parser yac1.tab.cc lex.yy.c testlex.cc -lfl
yac1.tab.cc: In function ‘int yyparse(void*)’:
yac1.tab.cc:1302:16: error: too many arguments to function ‘int yylex()’
yac1.yy:20:13: note: declared here
yac1.tab.cc:1510:24: error: cannot convert ‘const char*’ to ‘parsed_vals*’ for argument ‘1’ to ‘void yyerror(parsed_vals*, const char*)’
yac1.tab.cc:1625:35: error: cannot convert ‘const char*’ to ‘parsed_vals*’ for argument ‘1’ to ‘void yyerror(parsed_vals*, const char*)’
In file included from testlex.cc:3:0:
lexheader.h:278:1: error: ‘YYSTYPE’ does not name a type
lexheader.h:280:18: error: variable or field ‘yyset_lval’ declared void
lexheader.h:280:18: error: ‘YYSTYPE’ was not declared in this scope
lexheader.h:280:28: error: ‘yylval_param’ was not declared in this scope
lexheader.h:280:51: error: expected primary-expression before ‘yyscanner’
lexheader.h:328:17: warning: ‘yylex’ initialized and declared ‘extern’ [enabled by default]
lexheader.h:328:17: error: ‘YYSTYPE’ was not declared in this scope
lexheader.h:328:27: error: ‘yylval_param’ was not declared in this scope
lexheader.h:328:50: error: expected primary-expression before ‘yyscanner’
lexheader.h:328:59: error: expression list treated as compound expression in initializer [-fpermissive]
make: *** [parser] Error 1

我就是搞不清楚出了什么问题。

需要详细答复,但没有链接。

我已经提到这些链接

http://www.phpcompiler.org/articles/reentrantparser.html

http://plindenbaum.blogspot.in/2009/12/parsing-genetic-code-using-flex-and_14.html

以下是一些问题和相应的修复。

  1. lex1.llyac1.yy中删除yylex的原型。你不应该在任何地方自己定义它。

  2. yac1.yy:的开头附近添加两个#include

    #include "yac1.tab.hh"
    #include "lexheader.h"
    

    请确保它们按顺序,因为第一个定义了YYSTYPE,第二个定义了它。这是flex/bison lexer和解析器的一个已知问题。

  3. yac1.yy中修复了yyerror的原型和定义。应该是:

    void yyerror(const char *s);
    

    如果你需要一个额外的参数,为了你自己的目的,从你自己的调用,你不能期望解析器提供它。在这种情况下,请定义自己的错误处理程序并使用不同的名称。

完成所有这些之后,您的程序将使用Makefile进行编译。它是否如预期的那样有效,我不知道。