$ perl -e '$x=\&fff;print $x->(2)'
Undefined subroutine &main::fff called at -e line 1.
[download]

However, since the Name <Something> is declared without any content, it will complain when called.

If you happen to provide the content of the name <Something>, it works:

$ perl -e '$x=\&fff; sub fff{44};print $x->(2)'
44
[download]

I believe that it is close to the notion of "auto-vivification." An object is created within the interpreter to reflect the fact that you have referred-to this thing, and you see the (dummy) object that it made, but it has no actual definition and therefore no content. CORE::GLOBAL like all of CORE is a pseudo-namespace that exists because a namespace is needed not because it is actually real in the sense of other namespaces which appear in source code.

Yes auto-vivification is close, the analogy becomes clearer since there is a hash like syntax to access the CODE slot of a typeglob. (like *CORE::sleep{CODE} )

anyway the important question is to know if a real coderef exists.

That's why you can check this with exists &Func; (sic)

Cheers Rolf
_{(addicted to the Perl Programming Language :)
Wikisyntax for the Monastery}

G'day morgon,

I believe you're making incorrect assumptions about CORE::GLOBAL. Here's a repeat of your examples along with equivalents not involving CORE::GLOBAL.

$ perl -wle 'print \&CORE::GLOBAL::sleep'
CODE(0x224fcb8)
$ perl -wle 'print \&CORE::GLOBAL::hubbabubba'
CODE(0x1d4acb8)
$ perl -wle 'print \&hubbabubba'
CODE(0x255bcb8)
$ perl -wle '&CORE::GLOBAL::sleep(1)'
Undefined subroutine &CORE::GLOBAL::sleep called at -e line 1.
$ perl -wle '&CORE::GLOBAL::hubbabubba(1)'
Undefined subroutine &CORE::GLOBAL::hubbabubba called at -e line 1.
$ perl -wle '&hubbabubba(1)'
Undefined subroutine &main::hubbabubba called at -e line 1.
[download]

As you can see, the outcomes are the same with or without CORE::GLOBAL.

I can't really comment on internals: I'm not sufficiently versed in that area. There are, however, plenty of monks who can help with that.