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Diffstat (limited to 'pod/perlobj.pod')
| -rw-r--r-- | pod/perlobj.pod | 17 |
1 files changed, 14 insertions, 3 deletions
diff --git a/pod/perlobj.pod b/pod/perlobj.pod index f31ce2c993..7d7eee55a8 100644 --- a/pod/perlobj.pod +++ b/pod/perlobj.pod @@ -361,21 +361,32 @@ are inherited by all other classes: C<isa> returns I<true> if its object is blessed into a subclass of C<CLASS> -You can also call C<UNIVERSAL::isa> as a sub with two arguments. The -first does not need to be an object or even a reference. This -allows the ability to check what a reference points to, or whether +You can also call C<UNIVERSAL::isa> as a subroutine with two arguments. +The first does not need to be an object or even a reference. This +allows you to check what a reference points to, or whether something is a reference of a given type. Example if(UNIVERSAL::isa($ref, 'ARRAY')) { #... } +To determine if a reference is a blessed object, you can write + + print "It's an object\n" if UNIVERSAL::isa($val, 'UNIVERSAL'); + =item can(METHOD) C<can> checks to see if its object has a method called C<METHOD>, if it does then a reference to the sub is returned, if it does not then I<undef> is returned. +C<UNIVERSAL::can> can also be called as a subroutine with two arguments. +It'll always return I<undef> if its first argument isn't an object or a +class name. So here's another way to check if a reference is a +blessed object + + print "It's still an object\n" if UNIVERSAL::can($val, 'can'); + =item VERSION( [NEED] ) C<VERSION> returns the version number of the class (package). If the |