Mike, > I have a problem with a rule on a newly installed relay on which --lint > throws a warning on an old local rule, squawking about "Variable length > lookbehind not implemented". I simplified the rule trying to discover > the problem and it seems to be with the /i modifier: > > This rule does _not_ provoke the warning: > > /(?<!Best )\bRegards,/ > > while this does, > > /(?<!Best )\bRegards,/i > > warn: config: invalid regexp for rule MY_CLOSE: > /(?<!Best )\bRegards,/i: Variable length lookbehind not implemented > in regex m/(?i)(?<!Best )\bRegards,/ > > This is with perl 5.18.1 (openSUSE 13.1) > > On other boxes - with perl 5.10.0 and perl 5.16.2 - there is no problem > and I fail to see that there is any variable length in either regex. > > Writing the rule like so with an apparently useless /i modifier allows > the regex to pass the lint check: > > /(?<![Bb][Ee][Ss][Tt] )\b[Rr][Ee][Gg][Aa][Rr][Dd][Ss],/i > > Can somebody tell me what the problem might be?
The 'st' is apparently equivalent to some ligature or some other UTF-8 character, so you end up with an alternation of two different lengths, which can't be used for look-behinds. Use a character set modifier /a to restrict the matching to ASCII rules. Search for "Character set modifiers" in the perlre man page. So something like: /(?<!Best )\bRegards,/aai should do with perl >= 5.14 . Better yet, avoid lookbehinds. Mark
