Lex/Yacc: Print message before input

Hi,

I'm trying to figure out how I can display a message/prompt when using lex/yacc (flex/bison).

For instance, main looks like so:

int main(int argc, char *argv[])
{
    yyparse();
}

Which calls yacc, which calls yylex(). This yields a blank line waiting on STDIN. How can i display a message like...

message $ _

instead of

_

Where the underscore represents the cursor position, waiting on input from STDIN...

Forgot to mention, I'd like the prompt to be printed repeatedly... so before each time lex/yacc request input from stdin..

From stackoverflow

• Figured it out. I had to integrate it as an action in my yacc file.

  My mine looks like:

  int main(int argc, char *argv[])
  {
      prompt();
      yyparse();
  }
  

  And my yacc file (.y) looks like...

  stmnt
       : /* empty */
       | stmnt whatever { do_something(); prompt(); }
       ;
  

  So that each time it parses a stmnt (the top-level), it'll display the prompt afterwards.