Alt::Assert(3pm)

Usage

Assuming there is a CPAN module Foo::Bar and mst wants to write an ALTernate called Alt::Foo::Bar::MSTROUT.

In mst's Foo::Bar, there is the following line:

    use constant ALT => 'MSTROUT';

In the alt module:

    package Alt::Foo::Bar::MSTROUT;
    use Alt::Assert; # imports assert()
    1;

Users use mst's Foo::Bar as normal, just like they would use the original Foo::Bar:

    use Foo::Bar -various => [qw(weird import)], {API=>'things'};

or:

    require Foo::Bar;

If they want to assert they have the mst version, they can:

    use Foo::Bar -various => [qw(weird import)], {API=>'things'};
    use Alt::Foo::Bar::MSTROUT;

or:

    require Foo::Bar;
    require Alt::Foo::Bar::MSTROUT;
    Alt::Foo::Bar::MSTROUT->assert;

Overview

Alt::Assert can be used to assert that the loaded module is the wanted alternate implementation. Using the Synopsis' example, there can be different Foo::Bar installed, either from the original distribution, or from one of the alternate ones. Each alternate might be slightly incompatible with the original. The existence of Alt::Foo::Bar::MSTROUT in the installation does not necessarily ensure that the installed Foo::Bar is from the same alternate distribution, since an installer can replace Foo::Bar from another distribution. That is why one might need to do this assertion.

Releases

6 releases since Debian 8 (Jessie); the text changed 3 times.