Check::ISA - DWIM, correct checking of an object's class
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
This module provides several functions to assist in testing whether a value is an object, and if so asking about its class.
This function tests if $thing is an object.
$thing
If $class is provided, it also tests tests whether $thing->isa($class).
$class
$thing->isa($class)
$thing is considered an object if it's blessed, or if it's a GLOB with a valid IO slot (the IO slot contains a FileHandle object which is the actual invocant). This corresponds directly to gv_fetchmethod.
GLOB
IO
gv_fetchmethod
Just like obj but uses "DOES" in UNIVERSAL instead of "isa" in UNIVERSAL.
obj
"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.
isa
DOES
This is probably reccomended over obj for interoperability, but can be slower on Perls before 5.10.
Note that "DOES" in UNIVERSAL
Just like obj_does, but also returns true for classes.
obj_does
Note that this method is slower, but is supposed to return true for any value you can call methods on (class, object, filehandle, etc).
Look into autobox if you would like to be able to call methods on all values.
Checks if $thing is an object or class, and calls can on $thing if appropriate.
can
UNIVERSAL, Params::Util, autobox, Moose, asa
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.
darcs send
Yuval Kogman <nothingmuch@woobling.org>
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.
To install Check::ISA, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Check::ISA
CPAN shell
perl -MCPAN -e shell install Check::ISA
For more information on module installation, please visit the detailed CPAN module installation guide.