Ignoring errors in yacc/lex

Question

I'm new to yacc/lex and I'm working on a parser that was written by someone else. I notice that when an undefined token is found, the parser returns an error and stops. Is there a simple way to just make it ignore completely lines that it cannot parse and just move on to the next one?

Answer 1

just add a rule that looks like

. {
  // do nothing
}

at the bottom of all of your rules, and it will just ignore everything it comes across that doesn't fit any of the previous rules.

Edit: if you have multiple states, then a catch-all that works in any state would then look like:

<*>. {

}