Loop Until Ignores Variables

Panorama X
1

Loops set to loop until the value of a variable don’t loop.

FileGlobal fgCount
fgCount = 3

Loop
Message “X”
until fgCount

Loop
Message “Y”
until 3

2

The Help file for until states it can only be used with a single integer constant when used to specify the number of loops. If you want to use a variable you would have to go with the for statement instead of the loop.

for fgCount,1,fgCount
    Message “X”
endloop
3

I don’t get the same meaning out of the Help on that one, and I’m inclined to believe it’s a minor bug. Especially since it’s valid in Panorama 6. But there are a number of ways to make it work in PanX including the way you’ve noted.

4

Valid point. It should preferably be corrected to comply with the action in Panorama 6 or, at the least, the change should be noted in the Help file.

5

Gary is reading the help topic the way I intended. The help file says that it must be a constant number with no calculations. A variable is not a constant number. I suppose the text could be modified to specifically mention that variables are not allowed. Ok, I just went to make that change and someone beat me to it! Probably Gary, so thanks!

I am actually quite surprised that this would work in Panorama 6, that wasn’t my recollection. I went back and tested it, and it does in fact work, my recollection was wrong. I think that was actually a bug, which is why I wouldn’t have known. It was not documented to work that way, in fact the Programming Reference wizard shows different code needed to use a variable, like this:

fileglobal fgCount
fgCount = 3
loop
    fgCount=fgCount-1
    ...
until fgCount=0

Let me explain why I think Panorama 6 has a bug and that the way Panorama X works is correct. The way the loop/until was intended to work it would be perfectly valid to write code like this:

let loopOver=false
loop
    ...
    if something
        loopOver=true()
    endif
    ...
until loopOver

But in Panorama 6 apparently this won’t work, because the value of false() is zero and true() is -1 (which is a really huge number when treated as an unsigned number, which it would be here). So in Panorama 6 the loop would either run once (the value is false, which is zero), or the loop would continue millions of times. But it wouldn’t stop when you planned it to.

6

No, it wasn’t me. :innocent:

7

Aha – it looks like Thomas Cooper actually submitted this change back in June!