Global variables and Functions

[Janet]

As a general rule, I don't use GLOBAL much. I prefer to store global variables in an array. This may be well known to those who use GLOBAL more often. I just stumbled across this.

Setting a variable to GLOBAL, if that variable is also the name of a Function, will cause the variable to be 0 at all times, both inside the function itself and upon return from the function.


   Global randomNumber ' Remove this line to see difference
   Cls
   randomNumber = randomNumber()
   Print "Return from function: randomNumber = ";randomNumber
End

Function randomNumber()
   randomNumber = Int(Rnd(1) * 25) + 1
   Print "Inside function: randomNumber = ";randomNumber
End Function


Again, I may have just stumbled across a practice that more experienced users would shun from the start. A similar event happens in Liberty BASIC. The only difference is that inside the sub, the value is as set, then upon return, the value resets to 0. I checked the Help File in Liberty BASIC and couldn't find anything there that said to avoid setting a Function variable as global either.

I'm not suggesting this is a bug. I'm just thinking a mention should be made in the LB, JB, and Run BASIC documentations.

[carlgundel]

janet said:

As a general rule, I don't use GLOBAL much. I prefer to store global variables in an array. This may be well known to those who use GLOBAL more often. I just stumbled across this.

Setting a variable to GLOBAL, if that variable is also the name of a Function, will cause the variable to be 0 at all times, both inside the function itself and upon return from the function.


   Global randomNumber ' Remove this line to see difference
   Cls
   randomNumber = randomNumber()
   Print "Return from function: randomNumber = ";randomNumber
End

Function randomNumber()
   randomNumber = Int(Rnd(1) * 25) + 1
   Print "Inside function: randomNumber = ";randomNumber
End Function


Again, I may have just stumbled across a practice that more experienced users would shun from the start. A similar event happens in Liberty BASIC. The only difference is that inside the sub, the value is as set, then upon return, the value resets to 0. I checked the Help File in Liberty BASIC and couldn't find anything there that said to avoid setting a Function variable as global either.

I'm not suggesting this is a bug. I'm just thinking a mention should be made in the LB, JB, and Run BASIC documentations.

Thanks Janet. I'm not sure what I think about this yet, but thanks for reporting it. I'm probably not going to call that a showstopper, but perhaps I should document it.

-Carl

[carlgundel]

Thanks Janet. I'm not sure what I think about this yet, but thanks for reporting it. I'm probably not going to call that a showstopper, but perhaps I should document it.

Actually I've decided to put a compile-time check in there to prevent declaration of globals that match function names.

Thanks again,

-Carl