Re: perl syntax oddity

On Thu, Sep 18, 2003 at 12:07:16PM +0300, Ilmari Karonen <[email protected]> wrote:
> I guess it's because for() localizes the variable it's iterating over, 
> and needs the glob for that.  Oddly enough, however, local() does not 
> accept a glob that way:

for $x () does a more complete localization than local($x) does:

use Tie::Scalar;
tie $x, "Tie::StdScalar";
sub checktie { print '$x is ', (tied($x)?'':'not '), "tied in $_[0]\n" }
for $x (1) { checktie('for') }
{ local $x; checktie('local($x)') }
{ local *x; checktie('local(*x)') }

>   sub getaglob {*foo}
>   $foo = "pong\n";
>   for ${&getaglob} ("ping ") { print $foo }
>   print $foo;
> 
> works, printing "ping pong", while:
> 
>   sub getaglob {*foo}
>   $foo = "pong\n";
>   { local ${&getaglob} = "ping "; print $foo }
>   print $foo;
> 
> fails with "Can't localize through a reference"!

This error seems to be removed in 5.8.1 and it works there (though the
error entry was erroneously left in perldiag).

But this prints "pingping":

sub foo:lvalue { $foo }
$foo = " pong\n";
{ local &foo; print $foo="ping" }
print $foo;