WC -Sx- Jones <[EMAIL PROTECTED]> wrote:
:
: [Becuase of a recent discussion on Postfix-users list]
: Would anyone like to expand/explain what, exactly, is //
: matching below:
The first iteration of the loop, // matches a
zero-length string. Each subsequent time it matches the
last successful match.
The gotcha is if there was a successful match
previous to the loop:
my $string = 'string';
$string =~ /d/;
while (<DATA>) {
++$idx; print "Line $idx - seen $_" if //;
}
Above there is no change since the first match
failed. Below we get a different result. Now, all
matches in the loop match the last successful match.
my $string = 'string';
$string =~ /i/;
while (<DATA>) {
++$idx; print "Line $idx - seen $_" if //;
}
If you want to be certain you are matching only
zero-length strings, use /()/.
while (<DATA>) {
++$idx; print "Line $idx - seen $_" if /()/;
}
I'm curious. What prompted the question?
HTH,
Charles K. Clarkson
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