Dear Monks

Recently, I have done some reading regarding "Tie" in perl. And I have an question:

package Tie::Constvar;
use Carp;
sub TIESCALAR {
    my ($class, $initval) = @_;
    my $var = $initval;
    return bless \$var => $class;
}
sub FETCH {
    my $selfref = shift;
    return $$selfref;
}
sub STORE {
    confess "cannot assign value to a constant!";
}

package main;
tie my $AVO, Tie::Constvar, 6;
print $AVO,"\n";

tie  $AVO, Tie::Constvar, 3;  #this works
print $AVO,"\n";

$AVO = 3;  #this will throw an exception!
print $AVO,"\n";

[download]

As you can see that we cannot assign a value to "$AVO" as "$AVO = 3". This is expected. However, after I "Tied" $AVO to 6, I can "Tie" it again with 3 which didn't generate any error.

This made me wonder if Tying a variable is not considered "assignment".

So, how does the tied variable associate with its underlying returned object by "TIESCALAR"? It seems a hash like association. Is this right?

Does anyone have any insight on this? Thank you

In reply to question regarding "Tie" in Perl by lightoverhead

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