On Sat, 3 Nov 2018 08:29:39 -0700 Paul Eggert <egg...@cs.ucla.edu> wrote:
> Norihiro Tanaka wrote: > > By this change, each fragment is divided into > > groups by whether the fragment includes back reference in a pattern or > > not. a frgment which includes back reference constitutes group, and all > > frgments which include back reference also constitute a group. > > Surely this is not sufficient. An invocation of grep like this: > > grep -E '(a > b)' > > should be an error, but with the proposed patch won't it be equivalent to > "grep -E '(a|b)'" since the pattern has no back-references? Even the pattern has no back-references, compilation by regex run for each line. So Syntax errors will be detected as even your present. 212: if (!regex_compile (dc, p, len, dc->pcount, lineno, !backref)) 213: compilation_failed = true; $ env LC_ALL=C src/grep -E '(a b)' ~/in src/grep: Unmatched ( or \(
