Re^2: A bug in regex with conditional subpattern?

and simply moves on to the next element.

And that's the bug, IMHO. If the yes-pattern is present, and the condition fails, the whole match normally fails. Why should it move on if the match fails? Compare:

'a' =~ /^xa/ # match of x fails, doesn't move on to match a
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When the no-pattern is not present, and the condition fails, it normally doesn't match:

$ perl -wE 'say "a" =~ /^(?(?=b)xxx)a/'

$ # no match
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So it doesn't show the "move on"-behavior when the yes-pattern is something else than the empty pattern.

So it's a special case. And it's not documented. So it's a bug.

Perl 6 - second systems done right

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Re^3: A bug in regex with conditional subpattern? by ig (Vicar) on Mar 17, 2011 at 18:00 UTC
Why should it move on if the match fails? Is "(?(condition)yes-pattern)" an abbreviation for "(?(condition)yes-pattern\|)" (i.e. with an explicitly empty no-pattern)? This seems most reasonable to me, but I find nothing in the documentation to suggest whether this or any other possibile behaviour should be expected. The most fundamental "bug" seems to be lack of documentation of intended behaviour.	[reply]
Re^4: A bug in regex with conditional subpattern? by moritz (Cardinal) on Mar 19, 2011 at 19:16 UTC
but I find nothing in the documentation to suggest whether this or any other possibile behaviour should be expected. fixed in blead Perl 6 - second systems done right	[reply]