Re: [Fun With Perl] How to swap $p and $q without $tmp

[merlyn@stonehenge.com (Randal L. Schwartz)]

>>>>> "Derek" == Derek Balling <dredd@megacity.org> writes:

Derek> I truly believe you wanted :

Derek> s/(It's)/\1, I say, \1/

Derek> There. Didn't you?

Nope.  The left side is a regex, where you use \1 to do a backreference.
The right side is a double-quoted string, where you use $1 to get
the most recently successful match's first memory, and \1 means
"control-A".

It is only by a bizarre special-casing that \1 happens to work on the
right of a s///, because too many people were using sed-like stuff in
s/// with early versions of Perl.  However, it probably won't work
once you get up to \10, which will probably always be a backspace.
$10 will *always* work.

Derek> (I'll feel really stupid if I'm wrong, since I sit next to
Derek> Jeffrey Friedl at work *grin*)

I'll drop him a note.  You should read his book sometime.  I'm pretty
sure he mentions this. :-)

-- 
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