> can find a way to do what I need with a single regex.

"single regex" is relative in Perl since you can include Perl-code investigating a sub-match

Does it must be a single regex, or is it just academic curiosity?

edit

you need a positive condition which allows to stop the non-greedy only if you have a match or you reached the end.

  DB<113> print join "|",'a<b1<b2' =~ /(a).+?(?:(c.)|$)/
a|

  DB<114> print join "|",'a<b1<c2' =~ /(a).+?(?:(c.)|$)/
a|c2

  DB<115> print join "|",'a<c1<c2' =~ /(a).+?(?:(c.)|$)/
a|c1

[download]

Try to apply this technique.

HTH

Cheers Rolf
(addicted to the Perl Programming Language and ☆☆☆☆ :)
Je suis Charlie!

In reply to Re^6: Regex Optional capture doesn't (updated) by LanX
in thread Regex Optional capture doesn't by NetWallah

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