&union and overlapping declarations

[Davide Rizzo]

I'm using Bison 1.24 together with Flex 2.5

I would like to define two different semantic types for my tokens and rules, so I specified the following:

%union {
   char* str;
   int integer;
}

%token <str>        IDENTIFIER WEEK HOUR DAY MONTH YEAR

%token <integer>    DAY_OF_WEEK MONTH_NAME DIGIT

%type  <integer>    input phrase note date_specification date date_stmt date_interval

%type  <integer>    time time_stmt time_specification time_interval

...etc...

in the declaration section. After having assigned each token and rule a semantic type, I arranged Flex to return the right values, eg:

[[:alpha:]]+        {
                      yylval = yytext;
                      return(IDENTIFIER);
                    } 
[0-9]+              {
                      yylval = atoi(yytext);
                      return(DIGIT);
                    }

Bison and Flex correctly generate the whole, but when I try to compile the code (using Dev-C++ 4.9 gcc compiler) I get some strange errors:

1. a "conflicting types for `typedef union YYSTYPE YYSTYPE' " error in the header file filename_tab.h generated by Bison where there is the definition
   typedef union {
      char* str;
      int integer;
   } YYSTYPE;
   equivalent to the %union specification
2. a "previous declaration as `typedef union YYSTYPE YYSTYPE' " error in the declaration section of Bison source file
   %union {
      char* str;
      int integer;
   }
3. a "conflicting types for `union YYSTYPE yylval' " error in the header file filename_tab.h generated by Bison where there is the definition
   extern YYSTYPE yylval;
4. a "previous declaration as `union YYSTYPE yylval' " error in bison.simple file at line 117
   YYSTYPE yylval;   /*  the semantic value of the  */
   

I guess there's something wrong with type definition/redefinition, but I cannot understand what I must change. Can you help me?

Thanks so much in advance, regards

Davide Rizzo