upvrar in namespace

[caesar]

Why can't use upvar on a variable that is defined outside the proc that is in a namespace?

I tried something like:

Code: Select all

namespace eval blah {
	set foo 1
	proc moo {x} {
		upvar #0 $x var
		puts $var
	}
}

and other ways but all fail. From what I read a upvar #0 should be the equivalent of a global call but that fails as well, meaning the var variable isn't created.

If I take the code outside the namespace then it's working as expected. What am I doing wrong?