Regular expression readability notwithstanding, I'm missing the point I guess.

I think readability was exactly his point. Use /x and comment where each capture starts. I see both of your points though I do think that hardburn went off on a bit of a tangent by bringing up /x in the first place. Using the modifier certainly doesn't make it any easier to deal with the two sets of parens in your code, just in your mind.

The easiest solution I see to the counting problem is just to wrap the entire expression in an outter set of parens so that $1 captures both the right or the left side of the alternation.

But you can't do that because then you'd be capturing the 'X' in the first alternative which is just what you want to avoid.

But the point is moot I guess, since sauoq's answer seems to have solved the OP's problem in a more graceful way anyway.

Or not. The problem being that he never really did tell us exactly what he wanted. Sigh and shrug.

-sauoq
"My two cents aren't worth a dime.";

Just to give an example of how /x can help here, look at the code below. Let us assume that $_ contains data in the form id|name|address|city|state|postal. So:

/\A (           # $1 -- Entire string (hey, why not?)
    ([^|]+) \|  # $2 -- id
    ([^|]+) \|  # $3 -- address
    ([^|]+) \|  # $4 -- city
    ([^|]+) \|  # $5 -- state
    ([^|]+)     # $6 -- postal
)\z/x;
[download]

IMHO, it's more impressive to make smart use of \x than being able to make use of bizzare regex features.

I remember reading in Exegisis (or whatever the doc is called) that the Perl 6 regex behavior will, among other things, default to /x type behavior.



Dave

Yes, in Perl 6, /x is on by default. It also has better support for named captures, so the example above can be expressed fine without the comments showing which numbered variable goes with which capture.

----
I wanted to explore how Perl's closures can be manipulated, and ended up creating an object system by accident.
-- Schemer

: () { :|:& };:

Note: All code is untested, unless otherwise stated