Re: Explanation of commonly used Perl

Unroll it, bit by bit:

`@_`	We'll take the parameters passed to the sub..
`{@_}`	..and make an anonymous hash out of them.
`{{@_}}{ ... }`	..now we're going to dereference this hashref..
`@{{@_}}{qw/ ... /}`	..but take a slice of it when we do so;
`@{{@_}}{qw/foo bar/}`	Specifically, we'll extract the foo and bar values from the hashref..
`my ($foo, $bar) = @{{@_}}{qw/foo bar/}`	..and put them into $foo and $bar

Essentially, the code is equivilent to the following, but avoids the %args variable:

sub foobar {
  my %args = @_;
  my $foo = $args{foo};
  my $bar = $args{bar};
}
[download]

perl -pe '"I lo*`+$^X$\"$]!$/"=~m%(.*)%s;$_=$1;y^`+*^e v^#$&V"+@( NO CARRIER'

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Re: Re: Explanation of commonly used Perl by perrin (Chancellor) on Apr 16, 2002 at 22:25 UTC
In my opinion, your translation is a whole lot easier to read and probably a better idea for maintainable code. The original is pretty obfuscated and would definitely confuse a beginner.	[reply]
Re: Re: Re: Explanation of commonly used Perl by Chmrr (Vicar) on Apr 16, 2002 at 22:30 UTC
I would agree. The only "advantage" to doing the hashref / dereference / slice trick is that one avoids the %args hash; frankly, I don't consider that an advantage at all. Most of the time when I pass args to a function as a hash, I simply use the %args hash in the function, instead of pulling specific values out and stuffing them into scalars. I like to think that this makes for better maintainability and scalability. But to each their own.. perl -pe '"I lo`+$^X$\"$]!$/"=~m%(.)%s;$_=$1;y^`+*^e v^#$&V"+@( NO CARRIER'	[reply]