Re^2: Best practices with globals and subroutine arguments

[desemondo]

Would it be useful then perhaps, to have the ablity to mark a variable as readonly if current scope is below the scope in which a variable was declared?

ie. Variable can only be modified within the scope it was declared and not somewhere below?

use strict; 
use warnings;
my $g1;    
my $g2    :resticted ;   #or some other attribute mechanism

$g1 = 'boo'; 
$g2 = 'blah';   

{
    $g1 = 'changed' ;        #OK. Same behaviour as now
    $g2 = 'cant change';     #Can't do this, ideally throw an exceptio
+n
    my $copy_of_g2 = $g2;    #OK. I can still read $g2.
}

print "$g1\n"
print "$g2\n"

__END__
changed
blah

I have no idea if this is possible (which I actually consider secondary), I'm asking if anyone else thinks this type of functionality would be useful to have. Or if this behaviour is already available which module(s) provide it.