NAME

       UNIVERSAL::can - work around buggy code calling UNIVERSAL::can() as a function

SYNOPSIS

       To use this module, simply:

         use UNIVERSAL::can;

DESCRIPTION

       The UNIVERSAL class provides a few default methods so that all objects can use them.  Object orientation
       allows programmers to override these methods in subclasses to provide more specific and appropriate
       behavior.

       Some authors call methods in the UNIVERSAL class on potential invocants as functions, bypassing any
       possible overriding.  This is wrong and you should not do it.  Unfortunately, not everyone heeds this
       warning and their bad code can break your good code.

       This module replaces "UNIVERSAL::can()" with a method that checks to see if the first argument is a valid
       invocant has its own "can()" method.  If so, it gives a warning and calls the overridden method, working
       around buggy code.  Otherwise, everything works as you might expect.

       Some people argue that you must call "UNIVERSAL::can()" as a function because you don't know if your
       proposed invocant is a valid invocant.  That's silly.  Use "blessed()" from Scalar::Util if you want to
       check that the potential invocant is an object or call the method anyway in an "eval" block and check for
       failure (though check the exception returned, as a poorly-written "can()" method could break Liskov and
       throw an exception other than "You can't call a method on this type of invocant").

       Just don't break working code.

AUTHOR

       chromatic, "<chromatic@wgz.org>"

BUGS

       Please report any bugs or feature requests to "bug-universal-can@rt.cpan.org", or through the web
       interface at <http://rt.cpan.org/NoAuth/ReportBug.html?Queue=UNIVERSAL-can>.  This will contact me, hold
       onto patches so I don't drop them, and will notify you of progress on your request as I make changes.

ACKNOWLEDGEMENTS

       Inspired by UNIVERSAL::isa by Yuval Kogman, Autrijus Tang, and myself.

       Adam Kennedy has tirelessly made me tired by reporting potential bugs and suggesting ideas that found
       actual bugs.

       Mark Clements helped to track down an invalid invocant bug.

       Curtis "Ovid" Poe finally provided the inspiration I needed to clean up the interface.

       Peter du Marchie van Voorthuysen identified and fixed a problem with calling "SUPER::can".

       Daniel LeWarne found and fixed a deep recursion error.

       Norbert Buchmüller fixed an overloading bug in blessed invocants.

       The Perl QA list had a huge... discussion... which inspired my realization that this module needed to do
       what it does now.

COPYRIGHT & LICENSE

       Copyright (c) 2005 - 2014, chromatic. This module is made available under the same terms as Perl 5.12.

perl v5.36.0                                       2022-10-13                                UNIVERSAL::can(3pm)