Re: Action at a great distance

This is a bad idea because ..

The same set of @args are passed as ALIASES to the subs. The subs could modify the @args and have un-intended side effects.

Here is an easy, possibly inefficient workaround by copying the @args:

foreach (@callbacks) {
  $_->((@args));
}
[download]

Update: Oops - this was untested. Use $_->( @{ @args } );

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Comment on Re: Action at a great distance Download Code

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Re: Re: Action at a great distance by chromatic (Archbishop) on Mar 17, 2004 at 19:46 UTC
Did you test this? `use strict; use Test::More tests => 1; my @cb = ( sub { $_[0] = reverse $_[0] }, sub { $_[1] = reverse $_[1] }, ); my @args = qw( one two ); for my $cb (@cb) { $cb->((@args)); } is_deeply( \@args, [qw( one two )] );` [download] Besides that, any argument passing in Perl has that drawback.	[reply] [d/l]
Re: Re: Action at a great distance by etcshadow (Priest) on Mar 17, 2004 at 20:13 UTC
Dude... those parentheses don't cause the array to be copied. If you want do an in-line copy like that, I recommend: `foreach (@callbacks) { $_->( @{[ @args ]} ); }` [download] `------------ :Wq Not an editor command: Wq` [download]	[reply] [d/l] [select]
Re: Re: Re: Action at a great distance by Anonymous Monk on Mar 18, 2004 at 07:42 UTC
bracket happy? :) `$->( @{ \@args } );` [download]	[reply] [d/l]
Re: Re: Re: Re: Action at a great distance by etcshadow (Priest) on Mar 18, 2004 at 07:54 UTC
bracket happy? :) `$->( @{ \@args } );` No, actually... by saying `@{ \@list }`, you're just referrencing and dereferrencing the same list. In order to make an inline copy of the list, you'd need to add back in there a second, new (anonymous) array. `[me@host]$ perl -le 'sub foo { $_[0]++ } @x = (0,1); foo(@x); print "@ +x"' 1 1 [me@host]$ perl -le 'sub foo { $_[0]++ } @x = (0,1); foo(@{ \@x }); pr +int "@x"' 1 1 [me@host]$ perl -le 'sub foo { $_[0]++ } @x = (0,1); foo(@{[ @x ]}); p +rint "@x"' 0 1 [me@host]$` [download] Please... if you're going to "correct" someone, then make sure that you are correct and that (s)he is incorrect. `------------ :Wq Not an editor command: Wq` [download]	[reply] [d/l] [select]
Re: Re: Action at a great distance by Fletch (Bishop) on Mar 17, 2004 at 20:53 UTC
Erm, and that's any different than explicitly calling multiple subs with the same array as an argument how? Just because you're using a coderef to call it or not doesn't change the fact that subs receive aliases. `## I.e. just as "dangerous" foo( @args ); blah( @args ); zorch( @args );` [download]	[reply] [d/l]