NAME

Check::ISA - DWIM, correct checking of an object's class

SYNOPSIS

        use Check::ISA;

        if ( obj($foo, "SomeClass") ) {
                $foo->some_method;
        }


        # instead of one of these methods:
        UNIVERSAL::isa($foo, "SomeClass") # WRONG
        ref $obj eq "SomeClass"; # VERY WRONG
        $foo->isa("SomeClass") # May die
        local $@; eval { $foo->isa("SomeClass") } # too long

DESCRIPTION

This module provides several functions to assist in testing whether a value is an object, and if so asking about its class.

FUNCTIONS

obj $thing, [ $class_or_role ]

This function tests if $thing is an object.

If $class_or_role is provided, it also tests tests whether $thing->DOES($class_or_role).

"DOES" in UNIVERSAL is just like isa, except it's use is encouraged to query about an interface, as opposed to the object structure. If DOES is not overridden by th ebject, calling it is semantically identical to calling isa.

$thing is considered an object if it's blessed, or if it's a GLOB with a valid IO slot (this is a FileHandle object).

inv $thing, [ $class_or_role ]

Just like obj, but also returns true for classes.

obj_can $thing, $method

inv_can $thing, $method

Checks if $thing is an object or class, and calls can on $thing if appropriate.

VERSION CONTROL

This module is maintained using Darcs. You can get the latest version from http://nothingmuch.woobling.org/code, and use darcs send to commit changes.

AUTHOR

Yuval Kogman <nothingmuch@woobling.org>

COPYRIGHT

        Copyright (c) 2008 Yuval Kogman. All rights reserved
        This program is free software; you can redistribute
        it and/or modify it under the same terms as Perl itself.