Sure you can use global variables in Subroutines,
And you can get values returned to you from the subroutine,

But what you can't do with PBP, is embed a call to a subroutine (function) and have the result returned into the current formula.

I'm sure what everyone wants is to do something like this.
Code:
Function  Val(str as String) : as WORD
    ,,,,
End Function

' And then be able to 

MyVar = 100 * Val(MyString) + 10 / 2
Never going to happen with PBP.

There's lots of ways to do the same thing. But the easy way? Nope!
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