Syntax error if paragraph contains more than 1 printable character

[Steve Litt]

Hi all,

I'm creating a parser that takes a text file whose paragraphs are
separated by blank lines. Unfortunately, if the input file contains a
paragraph with more than one non-space character, it gives me a syntax
error via yyerror(). So the following works, where ===== etc are not in
the inpyut file but just signify beginning and end of file:

================
a

b

c

================

The following throws a syntax error:

================
a

bx

c

================

The following also throws a syntax error:

================
a

b
x

c

================

I'd appreciate any guidance as to what is wrong with my Flex and Bison
programs (I suspect my rules in the rules section of Bison). My Flex
and Bison programs follow, once again delineated by lines of equal
signs that don't exist in the program:

======= Flex Program =========
%option noinput nounput
%{
#include "paragraphs.tab.h"
%}
  
%%

[ \t]*\n    {strcpy (yylval.y_char, yytext); return NL;  }
.           {strcpy (yylval.y_char, yytext); return PARATEXT; } 

%%


int yywrap(void)
{
     return 1;
}

int yyerror(char *errormsg)
{
      fprintf(stderr, "%s\n", errormsg);
      exit(1);
}
================


======= Bison Program =========
%{

#include <stdio.h>
#include <stdlib.h>
int yylex(void);
int yyerror (char *errmsg);
#define EOF_ 0
%}

%union {
        char    y_char [10000];
}
%token <y_char>   PARATEXT
%token <y_char>   NL
%%

wholefile : wholefile2 {printf("End of file.\n");};

wholefile2 : toptrash {printf("Beginning of file.\n");}
  multichunk {printf("dia multichunk\n");}
;

toptrash : %empty {printf("dia empty multitrash\n");}
  | toptrash {printf("dia another toptrash\n");}
  NL {printf("dia another NL in toptrash\n");}
;

multichunk : %empty {printf("dia empty multichunk\n");}
  | multichunk chunk {printf("dia multichunk chunk\n");}
;

chunk : PARATEXT { printf("%s %s\n", "PARATEXT", $1); }
  parend {printf("dia parend\n");}
;

parend : 
  multinewline {printf("dia multinewline\n");}
  | YYEOF {printf("dia YYEOF\n");}

multinewline : NL  { printf("%s%s", "NL_tok1",$1); }
  NL   { printf("%s%s", "NL_tok2",$1); }
  | multinewline NL   { printf("%s\n", "dia multinewline NL"); }
;

%%

int main(int argc, char *argv[]){
        printf("\nStarting...\n");
        printf("dia value of YYEOF is %d\n", YYEOF);
        yyparse();
        printf("\nFinished...\n");
}

================

Thanks,

SteveT

Steve Litt 

Autumn 2023 featured book: Rapid Learning for the 21st Century
http://www.troubleshooters.com/rl21