On Mon, 21 Mar 2011, ND wrote:
> PCRE version 8.11 2010-12-10
> /\A(?!(?:a(*THEN)b))/
> ac
> No match
There was special code for the final alternative of a non-capturing
parenthesized subpattern. It reduced stack usage by not recursing when
the result of the call would just be passed back from the current level.
However, now that (*THEN) exists, this optimization no longer works,
because the result of the recursive call has to be inspected to see if
(*THEN) was encountered.
I have committed a patch that fixes this bug by removing the
optimization. There was the same bug with the branches of a conditional
subpattern. This has also been fixed.
Philip
--
Philip Hazel
