in reply to Re: Why doesn't perl optimize this?
in thread Why doesn't perl optimize this?

Agreed!

Maybe clearer: [@a] creates the ref to a copy (and copying is expensive) while \@a is the ref to the original array (no costs!).

Cheers Rolf

( addicted to the Perl Programming Language)

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Re^3: Why doesn't perl optimize this?
by nbtrap (Sexton) on Jun 04, 2013 at 02:09 UTC
    I know the difference. My question was not about the difference, it was about why the difference is not optimized away in cases like the one I cited.
[reply]
      You seem to believe in magical powers of static code analysis in a dynamic language.

      plz tell me

       
sub func {
  my ($code,@a) = @_;
  my $b = [@a];
  eval $code;
  return $b;
}

      [download]

      How is the compiler supposed to know that '@a' can be destroyed w/o knowing what happens in '$code' at runtime?

      Cheers Rolf

      ( addicted to the Perl Programming Language)

[reply]
[d/l]
        I agree that the compiler can't know in the case you cite. But what about the case I cited?
[reply]

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