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Author image Marty O'Brien


Forks::Super::Tie::Enum - tie'd scalar that can only hold values on a small list


    use Forks::Super::Tie::Enum;
    tie $next_action, 'Forks::Super::Tie::Enum', 'abort', 'retry', 'fail';
    $next_action = "abort";       # ok
    $next_action = "retry";       # ok
    $next_action = "go fishing";  # warning "Invalid assignment ..."


This package is part of the Forks::Super distribution. But it does not depend on any other part of Forks::Super and there is no reason it couldn't be extricated and used in a different context.

Scalar value where assignment will fail unless the new value is on a list of value provided when the tie is started. If you expect the value of $switch to be either "on" or "off" and if your script would fail catastrophically if a user tried to assign

    $switch = "cheesecake";

then this module might be for you!


    tie $var, "Forks::Super::Tie::Enum", @list;

Assigns the first element of the given @list to the scalar <$var>, and ignores any future attempts to assign a value to $var that was not in @list at the time of tie'ing.

Assigning an invalid value will cause this package to produce the warning message

    Invalid assignment to enumerated tied scalar.


Marty O'Brien, <mob@cpan.org>


Copyright (c) 2009-2018, Marty O'Brien.

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself, either Perl version 5.8.8 or, at your option, any later version of Perl 5 you may have available.

See http://dev.perl.org/licenses/ for more information.