BugReport using globals in sub for/next loop

[angusmann]

Hi all. I think this is a new bug.

If you declare a variable as global, then use it in a for/next loop within a subroutine it generates this error message :

Runtime Error in program 'untitled':
Message not understood: #lessFromInteger:

The code below will generate the error :

global x
call testsub
print "Finished."
end

sub testsub
print "Starting subroutine."
for x=1 to 10
print x
next x
end sub


[mackrackit]

Not sure if what you ran across is a bug...
Try this:

global x
x = 3
call testsub
print "Finished."
end

sub testsub
print "Starting subroutine."
for i=1 to 10
x=x+1
print x
next i
end sub

I put the x = 3 in so you can see it is a global.

[StefanPendl]

This is not a new issue, but it was only reported for Liberty BASIC currently.

You might have your reasons to use a global variable for a FOR..NEXT index, but I would never use one, since they are temporary.

[carlgundel]

It's a bug in the sense that hard errors like that are always bugs.

-Carl

Jun 2, 2008 10:02:00 GMT -5 mackrackit said:

Not sure if what you ran across is a bug...
Try this:

global x
x = 3
call testsub
print "Finished."
end

sub testsub
print "Starting subroutine."
for i=1 to 10
x=x+1
print x
next i
end sub

I put the x = 3 in so you can see it is a global.

[angusmann]

Jun 2, 2008 10:11:05 GMT -5 StefanPendl said:

This is not a new issue, but it was only reported for Liberty BASIC currently.
You might have your reasons to use a global variable for a FOR..NEXT index, but I would never use one, since they are temporary.

Good advice; I recognize that.
Personally I never use globals in this way but I declared one as global as part of a debugging process. I just wanted the calling routine to be able to see if the subroutine got to the end of the for-next loop. The easy way was to (temporarily) declare it global.

But instead of making bug-checking easier it added an extra bug!

[StefanPendl]

Jun 2, 2008 21:23:32 GMT -5 angusmann said:

I just wanted the calling routine to be able to see if the subroutine got to the end of the for-next loop. The easy way was to (temporarily) declare it global.

You can assign the last value of index to a global variable.
The index will be one more than the upper limit of the loop.

  global gx
  call testsub
  print gx
  print "Finished."
end

sub testsub
  print "Starting subroutine."
  for x=1 to 10
    print x
  next x
  gx = x
end sub