Re: Avoiding reference of sub optimization

UPDATE: I'm still not sure if this should be considered a feature or a bug. It's not the same as with other "data" structures:

A subroutine isn't a data structure. Note that the same happens with other literals:

#!/usr/bin/perl -l

sub gen_arr {
  my $inner =shift;

  print my $outer = \"foo";

  return $outer;
}

gen_arr gen_arr;
__END__
SCALAR(0x9400bc4)
SCALAR(0x9400bc4)
[download]

If you really must create different addresses, use eval:

my $outer = eval "sub {1;}";   # Different address each time.
[download]

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Re^2: Avoiding reference of sub optimization by LanX (Saint) on Mar 21, 2011 at 15:30 UTC
Just for clarity! It's not the literal which makes the difference but - as already suspected in the OP - the constant folding. `#!/usr/bin/perl -l sub gen_arr { my $inner =shift; print my $outer = \"foo$inner"; # still a literal but not constant a +nymore return $outer; } gen_arr gen_arr;` [download] `Use of uninitialized value $inner in concatenation (.) or string at /t +mp/tst2.pl line 6. SCALAR(0x912c760) SCALAR(0x912c9d0)` [download] Cheers Rolf	[reply] [d/l] [select]
Re^2: Avoiding reference of sub optimization by LanX (Saint) on Mar 21, 2011 at 15:05 UTC
> A subroutine isn't a data structure. Well obviously not in Perl, but there is a reason why I've put "data" into quotes. :) But thanks for the literal example, good point! š Cheers Rolf UPDATE: 1) and another example of constant folding.	[reply]