Magical Variables

• Perl's tie feature creates a magical variable

        tie %magical => 'Package', args...;

• This makes a call to Package::TIEHASH

        Package->TIEHASH(args...);

• Package::TIEHASH must construct an object, say $o

• $o and %magical are now associated

  • Attempts to read or modify %magical turn into method calls on $o

        ... = $magical{$key}       $magical{$key} = ...;  
        $o->FETCH($key)            $o->STORE($key, ...)

• This is how the various DBM modules work

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Copyright © 2003 M. J. Dominus