use Perl

• only partial closure (Score:1)

  by rjbs (4671)

  Maybe I'm missing something important here, but a closure is not necessarily fully stocked with all the enclosed memory space and data it will need, because this is always possible:
  
{
    my $x = 'default';
    sub xify_foo {
        my $foo = shift;
        $x = $foo->$x(@_)
    }
}

  
  xify_foo needs to get more information from the stack, so it's not an entirely closed operation. Your explanation may apply in part, but I always thoug

  --
  rjbs
  • $foo isn't a free variable (Score:1)

    by FoxtrotUniform (5412) on 2004.11.01 20:11 (#35685) Homepage Journal

    In your example, xify_foo by itself has one free variable: $x. $foo isn't free in xify_foo: it's given by the caller. Hence, xify_foo only needs to close over $x. Technically (at least by my way of thinking when I wrote the journal entry), the xify_foo closure has all the memory space it needs: $x in the closure, and $foo on the stack. That is, of course, nit-picking.

    This is the sort of thing I was handwaving about when I mentioned predicate logic. I suppose I should've gone into more detail. :-)

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