NAME

       Const::Fast - Facility for creating read-only scalars, arrays, and hashes

VERSION

       version 0.014

SYNOPSIS

        use Const::Fast;

        const my $foo => 'a scalar value';
        const my @bar => qw/a list value/;
        const my %buz => (a => 'hash', of => 'something');

SUBROUTINES/METHODS

   const $var, $value
   const @var, @value...
   const %var, %value...
       This the only function of this module and it is exported by default. It takes a scalar,
       array or hash lvalue as first argument, and a list of one or more values depending on the
       type of the first argument as the value for the variable. It will set the variable to that
       value and subsequently make it readonly. Arrays and hashes will be made deeply readonly.

       Exporting is done using Sub::Exporter::Progressive. You may need to depend on
       Sub::Exporter explicitly if you need the latter's flexibility.

RATIONALE

       This module was written because I stumbled on some serious issues of Readonly that aren't
       easily fixable without breaking backwards compatibility in subtle ways. In particular
       Readonly's use of ties is a source of subtle bugs and bad performance. Instead, this
       module uses the builtin readonly feature of perl, making access to the variables just as
       fast as any normal variable without the weird side-effects of ties. Readonly can do the
       same for scalars when Readonly::XS is installed, but chooses not to do so in the most
       common case. This may change in the future if someone takes up maintenance of Readonly,
       and the two modules may be convergence if that happens.

CAVEATS

       Perl doesn't distinguish between restricted hashes and readonly hashes. This means that:

        use Const::Fast;
        const my %a => (foo => 1, bar => 2);
        say 1 unless $a{baz}

       Will give the error "Attempt to access disallowed key 'baz' in a restricted hash". You
       have to use "exists $a{baz}" instead. This is a limitation of perl that can hopefully be
       solved in the future.

ACKNOWLEDGEMENTS

       The interface for this module was inspired by Eric Roode's Readonly. The implementation is
       inspired by doing everything the opposite way Readonly does it.

AUTHOR

       Leon Timmermans <fawaka@gmail.com>

COPYRIGHT AND LICENSE

       This software is copyright (c) 2010 by Leon Timmermans.

       This is free software; you can redistribute it and/or modify it under the same terms as
       the Perl 5 programming language system itself.