Re^6: type glob

Then you couldn't have multiple variables with the same name, as in:
my $x;

sub foo {
   my $x;
   my $x;
   {
      my $x;
   }
}

sub bar {
   my $x;
}
[download]

It seems to me that your code behaves almost exactly like

our $x;

sub foo {
    local $x;
    local $x;
    {
        local $x;
    }
}

sub bar {
    local $x;
}
[download]

(except that localising a variable twice doesn't warn, whereas mying twice does) ^*. Thus, I'm not sure that it's accurate to say that you can't have two variables, both with the same name, in the symbol table ^**. (You might respond that you can only access one of them at a time, but that's true for lexicals, too.)

^* Of course, since neither code does anything, this might be an even more vacuous statement than is usual for me. :-)
^** Ah, but the $x of local $x is the same variable as that of our $x, whereas the $x of my $x is not the same variable as that of the other my $x.

Comment on Re^6: type glob Select or Download Code

Replies are listed 'Best First'.
Re^7: type glob by ikegami (Patriarch) on Nov 18, 2009 at 19:03 UTC
`local` doesn't create variables. It just backs up the value of the variable and restores it later. While it reduces the problems of using global variables, it doesn't remove them all.	[reply] [d/l]
Re^8: type glob by JadeNB (Chaplain) on Nov 18, 2009 at 20:29 UTC
`local` doesn't create variables. It just backs up the value of the variable and restores it later. I know ^. Certainly there's an internal difference; but it seems to me that the casual user is not likely to encounter much difference between `our $x; CODE INVOLVING OUTER $x { local $x; CODE INVOLVING INNER $x }` [download] and `my $x; CODE INVOLVING OUTER $x { my $x; CODE INVOLVING INNER $x }` [download] That's by no means to say that there is no difference—indeed, `our $x; my $y; sub twiddle { $x = $y = 'twiddled' } { local $x = 'local?'; my $y = 'local!'; twiddle; say $x, ', ', $y; }` [download] shows that there is—just that one's not likely to see it in casual use. ^ Ah, but re-reading shows that I didn't seem to understand: I said something about having two variables with the same name, when really the `local`ised `$x` is the same variable as the original one, just with a ‘temporary’ value. Is that misstatement on my part what you were correcting?	[reply] [d/l] [select]
Re^9: type glob by ikegami (Patriarch) on Nov 18, 2009 at 22:55 UTC
just that one's not likely to see it in casual use. If a child scope has a variable with the same name as its parent scope, it would look like `my $x; sub foo { ... $x ... } sub bar { ... my $x ... }` [download] What you said boils down to saying `bar` is unlikely to call `foo`, and I don't see how that is true. I it is unlikely that the same var name is used at two levels in a working program, but that's something else.	[reply] [d/l] [select]