On Sun, Apr 2, 2023 at 11:30 AM Paul Eggert <egg...@cs.ucla.edu> wrote: > > Also, GNU grep -w passes the following more-complicated regexp to dfaparse:
but AFAIK `-w` is not necessary to trigger it, as the following also infloops in Fedora Rawhide $ echo a | grep -E '((()|a)|())+' interestingly; the loop is broken if any character is added to any of the `()` branches which might mean that this is also unlikely to happen in well formed expressions. Carlo PS. -P doesn't loop and neither does `echo a | grep -E '((a|())|())+'` nor '(()|(a|()))+` nor `(()|(()|a))+'`
