[pcre-dev] Capturing duplicate named subpatterns in conditio…

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Szerző: Ahmad Amireh
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Címzett: pcre-dev
Tárgy: [pcre-dev] Capturing duplicate named subpatterns in conditional branches always refers to the last
Hi,

I'm having trouble figuring out how to capture duplicate named
subpatterns (as allowed by the PCRE_DUPNAMES option). My initial
understanding from reading the manual was that I could refer to a
subpattern(s) capture using a name instead of the capture order number.
While that is true, it seems the named subpattern capture always refers
to the _last_ branch in which it was _defined_ and not necessarily
matched. The example in the manual is almost exactly like what I'm
trying to do so I'll just use it to explain:

(?J)(?<DN>Mon|Fri|Sun)(?:day)?|(?<DN>Tue)(?:sday)?|(?<DN>Wed)(?:nesday)?|(?<DN>Thu)(?:rsday)?|(?<DN>Sat)(?:urday)?

Since only _one_ (or none) of these branches would be captured, I expect
<DN> to contain the capture from _that_ branch and not the last. Right
now it returns false for all subject except for "Saturday". Did I
misunderstand the usage of the PCRE_DUPNAMES option or is this a bug?

PS: I've tried using the branch resetting feature ( (?|) ) and it does
indeed solve the above but it doesn't satisfy my requirements since it
enforces the subpatterns to be identically named (by order).

Thanks for your time!