Freek de Kruijf <f.de.kru...@gmail.com> writes:
> Hi,
>
> I am trying to understand fully a perl program with the following lines:
>
> } elsif( /^(\#?\s*(?:pickup|qmgr)\s+)(?:fifo|unix)(\s+.*)/ ) {
> if( defined $normalize->{$1} ) { next; } else { $normalize->{$1} = 1; }
> I do understand the first line, but I can not find what the second line is
> about.
$1 contains the content of the first capturing group in the matching
regexp. in this case, "#pickup", "#qmgr", "pickup", "qmgr"... etc.
$normalize->{$1} means: getting the corresponding value of $1 from the
HashRef $normalize.
$normalize->{$1} = 1 means: setting the corresponding value of $1 to 1.
`next` is a keyword for skipping the rest of loop, so it would seem to
me that these 2 lines is inside of a loop. I'm guessing $_ is the
iterator of the loop. Assuming that's the case, it appears to me
$normalize is used to keep track the occurance of the captured
words. Not how may times they occur, just if they occur or not.
--
Cheers,
Kang-min Liu
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