Re: Passing an anonymous block to a method.

[kennethk]

According to Prototypes in perlsub it's possible:

sub mygrep (&@) mygrep { /foo/ } $a, $b, $c

However, I seem to remember a thread a few months back where a monk said it was not worth the hassle. Example lifted from the docs:

#!/usr/bin/perl
use strict;
use warnings;

sub mygrep (&@) {
    my $code = shift;
    my @result;
    foreach $_ (@_) {
        push(@result, $_) if &$code;
    }
    @result;
}

print join "\n", mygrep { /a/ } qw(cat hat bed den);

Update: I did some searching , but did not uncover the article I was thinking of. I did come across some thoughts from GrandFather, but they did not contain a compelling argument, at least to my eyes.

Update 2: And disregard the above. Somehow I hadn't processed the word "method" from the above.

[Corion]

Unfortunately not, for two reasons:

• Prototypes are disregarded when a code block is invoked as a method (see perlsub).
• & as a prototype only works if it is in the first position. $& does not allow to leave the sub from the second parameter.

[BrowserUk]

Unfortunately (but very usefully), that is being called as a subroutine, not a method. And method syntax doesn't respect prototypes :(