Alt::Assert(3pm) | User Contributed Perl Documentation | Alt::Assert(3pm) |
Alt::Assert - Assert alternate module implementation
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;
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.
Ingy doet Net <ingy@cpan.org>
Copyright 2012-2014. Ingy doet Net.
See <http://www.perl.com/perl/misc/Artistic.html>
2014-12-29 | perl v5.20.2 |