> My point is simply that Perl doesn't give you any guarantee except "we will try to parse it". Perl 6 gives you pretty good control over where to use backtrac

> My point is simply that Perl doesn't give you any guarantee except "we will try to parse it". Perl 6 gives you pretty good control over where to use backtracking and where not. It parses regular languages with a NFA or DFA, and can switch to a backtracking engine. More details in https://www.apress.com/us/book/9781484232279 https://www.apress.com/us/book/9781484232279 (sorry for the plug, wrote it myself).