Of course it is possible to use the $_[CONST] (I do it myself from time to time), the problem is that the scope of the CONST is too wide. The constant is "global", defined in a package, so all subroutines in that package might use it, even if it doesn't make sense there. And if I had two functions that have the "conceptualy same" parameter on a different place I'd have to define two constants with similar names, which could be very confusing.

Besides with the alias you can/could do something like

sub foo {
 alias ($_[0] eq 'whatever' ? $_[1] : $_[2]) => my $x;
 ...
}

[download]
How's that written with constants?

Another case when I'd love to have a lexical alias is when the function gets an array or hash reference, I do want to modify the array/hash, but do not like to have to dereference it all the time:

sub foo {
  my ($aref) = @_;
  alias @$aref => my @ary;
  ... do something with @ary
}

[download]
You are right about the speed issues, but that's not the point. Readability is the main concern here.

P.S.: Thinking about it some more. It's better that the alias() doesn't my() the variable.

Jenda
Always code as if the guy who ends up maintaining your code will be a violent psychopath who knows where you live.
   -- Rick Osborne

Edit by castaway: Closed small tag in signature

In reply to Re: Re: Lexical::Alias & subroutines by Jenda
in thread Lexical::Alias & subroutines by Jenda

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