If there was no x in the comment the second one would still match at the final x. Could it be that the pattern you want is something like $str =~ m/(^|$c) x/? Because even if there wasn't an x in the comment in the latter example, your pattern would still match the final x. Because it is an x preceeded by 0 comments.

In general you have a more basic problem. Which is that you're trying to use regular expressions for parsing, which they are poorly suited for. Instead you want to use regular expressions for tokenizing, and then move parsing logic into code. The basic trick for that is to use pos and the \G assertion liberally within regular expressions using the /g modifier.

In reply to Re: How do I avoid regex engine bumping along inside an atomic pattern? by tilly
in thread How do I avoid regex engine bumping along inside an atomic pattern? by zemane

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