Using Scalar::Util

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While attending YAPC::NA last week, a talk brought the Scalar::Util 
module to my attention. Specifically, the blessed() function. This is a 
neat way to tell if a particular scalar is a blessed object.

How does this relate to Class::DBI? There are LOTS of checks in method 
calls to make sure it is called either as an instance or class method. 
They all use something like

sub foo {
   my $self = shift;
   # only called as instance method
   return unless ref $self;
}

I propose that C::DBI should use blessed() instead since it's a better 
check. If Tony agrees, I'd be willing to submit a patch. The relevant 
docs are below. The changes should be pretty easy to make.

Drew

> http://search.cpan.org/~gbarr/Scalar-List-Utils-1.14/lib/Scalar/Util.pm
> blessed EXPR
> 
>     If EXPR evaluates to a blessed reference the name of the package that it
> is blessed into is returned. Otherwise undef is returned.
> 
>    $scalar = "foo";
>    $class  = blessed $scalar;           # undef
> 
>    $ref    = [];
>    $class  = blessed $ref;              # undef
> 
>    $obj    = bless [], "Foo";
>    $class  = blessed $obj;              # "Foo"

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