>>>>It is not a clean solution.
>>>>After subprocedure header, and before private variable is declared, public variable is not hidden and it is accessible.
>>>
>>>Then put it in the header: name your parameter the same as the public variable. Of course, you will completely confuse yourself and anyone looking at the code, but you won't be able to touch or see PubVar :).
>>
>>You are very close. But you use the name of the variable in subroutine header. So, how to do it without even mentioning PubVar in the subroutine?
>
>Now I'm very far... even using "local all like *" leaves you open between the header and that line.
>
>Fabiooooo! What's he talking about?

Aha, finally I make you cry!
To make a story short.
I was appointed to take care of a "legacy" application that was distributed and sold to many clients since at least 1994. As usual, no documentation, no database map, and the only programmer who knew the application, he diseased.
Application is written in the very interesting way. To name a few amazing things: there is no general on error routine, there is no onerror routine that store detailed information, nearly each subroutine has its own on error procedure, basically to prompt client to call the company representative, but mainly to ignore the error and let user to continue. And there are 400+ prg, and 400+ scx,....

Regarding what I call "interview question".
Sure enough, it is not the first time I laugh and ask myself, what is going on, why on earth it was implemented this way, etc.
In the main program public variable are declared. And then there are a huge number of the subsequent chain procedure calls.
Somewhere public variable disappears (sure, the error is ignored). It appeared that this subroutine is the 16th in the chain.
And how it disappeared, if it was not mentioned anywhere in the chain since # 9 in this chain?
Because #10 was called with parameters like:

Do subrotuine_10 with PubVar

Start your Monday laughing.