Re: Expunge implicit @_ passing

[Michael G Schwern]

On Mon, Aug 27, 2001 at 10:48:55AM -0400, Ken Fox wrote:
> Michael G Schwern wrote:
> > I can't think of any reason why this feature is useful anymore, and it
> > can be a really confusing behavior, so what say we kill it in Perl 6?
> 
> I've always thought is was pretty useful for implementing generic
> redirectors. I wrote a frame system that allows instances to over-ride
> class methods. The basic idea is
> 
>   sub foo {
>     my $method = $_[0]{"_foo"} || $_[0]->can("_foo");
>     &{$method};
>   }

Why not just $method->(@_); or &{$method}(@_); or goto $method?

Any time you want to implicitly pass @_, you can just as easily
*explicitly* pass it or use goto.  As we're not doing pass-throughs
all over the place, it's not the sort of thing you want implicit, as
opposed to, say $_.

OH!  Right, $_.  Consider this.

    sub foo {
        my $arg = shift || $_;

        print $arg;
    }

    sub bar {
        $_ = 'from default';
        &foo();
    }

    bar("from args");

What does that program do?  Change &foo to foo() or &foo() and the
behavior changes.  Ahh yes!  Confusing, isn't it?

Why am I beating this dead horse?

-- 

Michael G. Schwern   <[EMAIL PROTECTED]>    http://www.pobox.com/~schwern/
Perl6 Quality Assurance     <[EMAIL PROTECTED]>       Kwalitee Is Job One
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