> I'm trying to stick to a general philosophy of what's in a reg-ex, and I can
> almost justify assertions since as you say, \d, ^, $, (?=), etc are these
> very sort of things. I've been avoiding most of this discussion because
> it's been so odd, I can't believe they'll ultimately get accepted. Given
> the argument that it's unlikely that (?{code}) has been implemented in
> production, I can almost see changing it's symantics. From what I
> understand, the point would be to run some sort of perl-code and returned
> defined / undefined, where undefined forces a back-track.
>
The proposal that MJD and I were working on still has a lot of rough
edges, which may not be resolvable before the deadline. It proposes a
mechanism which allowed the programmer to set up a block in which the
flow of control was determined by the success or failure of statements
within the block.
Regex matches always determined whether flow would continue forward or
back up; arbitrary Perl code did whatever it did; and a special
function (which we called 'test' for the lack of a better name) allowed
the programmer to use true/false conditions to force backtracking as
required.
MJD has had to withdraw from the development of the RFC, and it is not
absolutely complete, but I'm still interested in trying to see if it
can be generalized sufficiently to be a useful extension to the
language.
--- Joe M.
