I don't think it makes semantic sense for exists to be applied to functions.

Nonetheless there are semantics for it.

sub E; # exists, but not defined
sub D { 1 }; # exists _and_ defined
# sub N does _not_ exist

$\="\n";

print exists(&N) ? "N exists" : "N doesn't exist";
print exists(&E) ? "E exists" : "E doesn't exist";
print exists(&D) ? "D exists" : "D doesn't exist";

print defined(&N) ? "N is defined" : "N is not defined";
print defined(&E) ? "E is defined" : "E is not defined";
print defined(&D) ? "D is defined" : "D is not defined";
__END__
N doesn't exist
E exists
D exists
N is not defined
E is not defined
D is defined
[download]

Assuming of course, that &foo is equivalent to "simple var" in your sense. If you see globs as aggregates then defined &foo makes sense. And it's easy to see globs as aggregates, as you can do *foo{THING}. So defined (and exists) applied to global things would just translate to check the "slot in the glob" determined by sigil. Now, I don't know what really goes on down there in perl land, but from the outside this picture works for me.

lodin