%{
#include <iostream>
using namespace std;

/* This is a nonsense grammar from a programming contest:
  the lowercase words are non-terminals, the uppercase characters
  are the terminals of this language.
 
  slurpy -> slimp slump
  slimp -> A H
        |  A B slimp C
        |  A slump C
  slump -> d_or_e f_string end
  d_or_e -> D
  d_or_e -> E
  f_string -> F f_string | F
  end -> slump
  end -> G
 
Some strings in the language: AHDFG, ADFGCDFFFFFG, ABAEFGCCDFEFFFFFFG
Some strings NOT in the lanuage: AHDFGA, DFGAH, ABABCC
*/
extern int lineno;
void yyerror(char *);
int yylex();
%}
%token EOLN
%%
 
slurpy_language :       slurpy_language slurpy
                |       slurpy
                ;
 
slurpy  :       slimp slump EOLN
        ;
 
slimp   :       'A' 'H'
        |       'A' 'B' slimp 'C'
        |       'A' slump 'C'
        ;
 
slump   :       d_or_e f_string end
        ;
 
d_or_e  :       'D'
        |       'E'
        ;
 
f_string:       f_string 'F'
        |       'F'
        ;
 
end     :       slump
        |       'G'
        ;
 
 
%%

void yyerror(char *s) {
   cout << "Syntax error on line " << lineno << endl;
}