On Tue, Nov 22, 2005 at 03:28:02PM +0100, Leopold Toetsch wrote:
> Below are two cases of inner subs in Perl5 and Python. The first
> (do_add3) is a plain nested subroutine, which is in the call chain. The
> second (mk_add3) uses a closure. perl5 can't deal with case 1 properly
> and warns.
>
> The question is: should Parrot cover case 1 too with :outer and it's
> default LexPad, or how would the code be translated to PIR?
>
> sub do_add3 {
> my $a = $_[0];
> sub add3 {
> $a + 3;
> }
> add3();
> }
What Perl 5 does with that case is just a plain old bug, or more
precisely, a consequence of how Perl 5 implements capturing a lexical
environment. It's just bad. Don't even try supporting it.
OTOH, that same case in Perl 6 is a normal closure and is supported with
the default LexPad:
.sub do_add3
get_params "(0)", $P0
.lex '$a', $P0
.lex '&add3', $P1
.const .Sub add3 = "add3"
$P1 = newclosure add3
$P1()
.end
.sub add3 :anon :outer(do_add3)
$P0 = fetch_lex '$a'
$P1 = $P0 + 3
.return ($P1)
.end
--
Chip Salzenberg <[EMAIL PROTECTED]>
