Thanks for the constructive comments - that's the kind of reply I was hoping for.

All points accepted. I tried to change it with your arguments in mind and noticed an obvious, major caveat along the way I hadn't picked up on before because I still don't fully grok typeglobs: it exports the entire typeglob - lock, stock and barrel. If an importing package already has a $foo_bar, this routine will overwrite the typeglob in the process of exporting &foo_bar, even if it never exports a $foo_bar of its own.

Oops.

That was not what I had in mind. So I pulled out my Camel and read up on typeglobs, the section that talks about the *sym{THING} syntax and tried grepping the list of slots of each glob. That works fine - except the SCALAR slot always contains a reference, whether such a package wide scalar has been named or not. In other words, if *x{SCALAR} is \undef, there is no way to know whether it wasn't mentioned at all (and should therefore not be exported) or it was mentioned in such as undef $x; or use vars qw($x); which define but do not assign a value to the variable.

Which means this approach is not viable..

Makeshifts last the longest.