Thanks Paul, Yitzle ..
On 31 May 2007 07:28:26 -0700, Paul Lalli <[EMAIL PROTECTED]> wrote:
On May 31, 10:15 am, [EMAIL PROTECTED] (Sharan Basappa) wrote:
> Thanks a lot Paul ..
>
> For this rule :
> $str = mississippi;
> $str =~ m/m(.*i)(.*pi)/;
>
> My initial understanding was that .*i would match all the way till last char
i.
> This would indeed be true if .*i was not followed by .*pi.
> Do you agree ?
Yes. Like you said initially - a regexp quantifier will match as much
as possible WITHOUT PREVENING THE MATCH FROM SUCEEDING. If the .*i
matched all the way up until the very last i, then the .*pi would fail
because there'd be nothing left to match.
FWIW, you can add:
use re 'debug';
to the top of your script to see exactly what Perl does when trying to
match a regexp. You'll see in this case that it first tries to
let .*i match all the way to the end, but then finds that .*pi now
fails, so it backtracks, letting the .* part of .*i match less and
less until .*pi can also match.
Paul Lalli
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