Re: Yet another regex bug.

[VSarkiss]

in reply to Yet another regex bug.

I would drive this from the principle that removing the comment should make no difference to what the program does. That is, your example should be exactly the same as /abc+/; it should match one or more c. If it's acting the same as /(?:abc)+/, I'd call it a bug.

[hossman]

That implies that "removing the comment" is the translation...

/abc(?#comment)+/  ----> /abc(?#comment)+/ /abc+/

Where as I (and evidently at least 2 other people) expect it to be the translation...

/abc(?#comment)+/  ------> /abc()+/

Updated: forgot to acctually make the translation i was trying to show.

[VSarkiss]

Well, your first line is the identity transformation, which isn't removing anything. ;-)

The parentheses surrounding the ?# are part of the syntax; that is, the comment marker in a regexp begins (?#, not ?#. (Check perlre: all the "funny" extended-pattern elements start with (?, one of the reasons being that it's a mnemonic to "question" what's coming next.¹) Thus if you're removing the comment you should remove the parentheses as well.

¹I don't buy the explanation, by the way, but it's there..