The magic you seek is UNIVERSAL::isa.

     if (UNIVERSAL::isa($self, __PACKAGE__)) {
         print "1st arg was object OR package name: ";
         $text = shift;
     } else {
         print "1st arg is just an arg: ";
         $text = $self;
     };
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I concur with dragonchild though: pick some subset of the 3 possible WTDI (function, class method, object method) and stick to it, and make it clear in the docs which is preferred. If people using the module get used to "Foo::bar(arg)" then what if some subs really must have the object passed in? Will it be easy to remember which form goes with which subroutine?

Personally, I think the sensible way is: public subroutines should be all methods or all functions (in which case it isn't an object package), or else mostly methods with a simple exported procedural function wrapping the most central method (see Data::Dumper). Private subs can vary freely, depending on if they manipulate object/class data or not. (And note this all assumes that speed isn't much of a factor - procedural function calls are always faster than methods.)

-- Frag.
"Never could stand that dog."