package UNIVERSAL;
+our $VERSION = '1.00';
+
# UNIVERSAL should not contain any extra subs/methods beyond those
# that it exists to define. The use of Exporter below is a historical
# accident that should be fixed sometime.
then a reference to the sub is returned. If it does not then I<undef>
is returned.
+C<can> cannot know whether an object will be able to provide a method
+through AUTOLOAD, so a return value of I<undef> does not necessarily mean
+the object will not be able to handle the method call. To get around
+this some module authors use a forward declaration (see L<perlsub>)
+for methods they will handle via AUTOLOAD. For such 'dummy' subs, C<can>
+will still return a code reference, which, when called, will fall through
+to the AUTOLOAD. If no suitable AUTOLOAD is provided, calling the coderef
+will cause an error.
+
C<can> can be called as either a static or object method call.
=item VERSION ( [ REQUIRE ] )
=item UNIVERSAL::isa ( VAL, TYPE )
-C<isa> returns I<true> if the first argument is a reference and either
-of the following statements is true.
+C<isa> returns I<true> if one of the following statements is true.
=over 8
-=item
+=item *
+
+C<VAL> is a reference blessed into either package C<TYPE> or a package
+which inherits from package C<TYPE>.
+
+=item *
-C<VAL> is a blessed reference and is blessed into package C<TYPE>
-or inherits from package C<TYPE>
+C<VAL> is a reference to a C<TYPE> of Perl variable (e.g. 'HASH').
-=item
+=item *
-C<VAL> is a reference to a C<TYPE> of perl variable (er 'HASH')
+C<VAL> is the name of a package that inherits from (or is itself)
+package C<TYPE>.
=back