\%class lex
    %{
    #include <iostream.h>
    #include "yacc.tab.h"
    #include <grammar/lex.h>
    %}
    %%
    [a-z]+ { return token(A,yytext); }
    [A-Z]+ { return token(B,yytext); }
    %%
  

    \%class yacc
    \%token  A B 
    %{
    #include <grammar/yacc.h>
    %}
    \%start sequence
    %%
    
    sequence : { cout << "empty\n"; }
             | A { cout << (char*) *$1 << " : A\n"; } sequence 
             | B { cout << *$1 << " : B\n"; } sequence 
             ;
    %%
  

    // file main.c 
    #include <grammar/lex.h>
    #include <grammar/yacc.h>
    
    main() { lex sc; yacc y(sc); y(); }