The user? The user doesn't use Perl, the developer uses Perl.

Why do you want a scalar and not a sub?

Anyway, others have already suggested assigning a reference to a literal (a literal is a readonly scalar variable, really!) to a typeglob, but there is a way to turn the readonly flag on during runtime, using xmath's Spy module, which unfortunately he never finished. 

use Spy;

my $foo = 123;
spy(\$foo)->readonly = 1;
$foo++;  # Modification of a read-only value attempted at - line 5.

[download]
Note that with Spy you can do evil things. Some variables are supposed to always be read-only. Like undef (${\undef}), true (${\!0}) and false (${\!1}). It's fun to make them writable, though, so feel free to experiment.

Juerd # { site => 'juerd.nl', plp_site => 'plp.juerd.nl', do_not_use => 'spamtrap' }

In reply to Re: There is a way to LOCK a SCALAR? by Juerd
in thread There is a way to LOCK a SCALAR? by gmpassos

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