Public Variable Declaration

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Doctor Watson
Posts: 8
Joined: Wednesday 22nd August 2018 7:55am

Public Variable Declaration

Post by Doctor Watson » Friday 05th April 2019 9:43am

Hi.
As I use a lot of For / Next loops in my program, I thought of using the same variables in each Sub, so I wanted to declare them as Public like I was used to in RealBasic. However, that seems not possible in Gambas. If I put f.e. :

' Gambas class file
Public x As Integer
-----------------------------------
Public Sub Form_Open()
For x = 1 To 10
‘Some code
Next
End
----------------------------------
I get : “Loop variable cannot be global .....”
Does this mean I have to keep declaring such variables in each Sub ?

Greetings

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Cedron
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Re: Public Variable Declaration

Post by Cedron » Friday 05th April 2019 2:50pm

Yes, but you can also use the following form (In more recent versions of Gambas):
For x As Integer = 1 To 10
  Print x
Next
Though my preference is to Dim them separately.

I did not realize you can't use a class level variable for an iterator, so I just learned something new.

Side note: The meaning of "Global Variable" is somewhat nebulous. In Gambas, since there are no "True Global Variables", the term seems to be used for what is more commonly called "Class Level", "Module Level", or even "File Level" variables.

You should be aware of is that the limits of For/Next loops are set before the first iteration and don't change after that. In other words, if you have an expression for the "To" or the "Step" value, it only gets evaluated once. To me, this is a good thing as it saves you from having to create a local variable for efficiency purposes.

Ced

stevedee
Posts: 110
Joined: Monday 20th March 2017 6:06pm

Re: Public Variable Declaration

Post by stevedee » Saturday 06th April 2019 10:54am

Doctor Watson wrote:
Friday 05th April 2019 9:43am
...I get : “Loop variable cannot be global .....”
I didn't know that either, but there are potential dangers in trying to do this. If your code contains "Wait" instructions you could end up with a new loop starting before the first had finished, which would reset x.

You can of course use code snippets if you have enabled these via Tools > Preferences > Code Snippets.

For example, create a new code snippet with the trigger string: dx
...and the code: Dim intX as Integer

Then in your code, you just type: dx <TAB>

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cogier
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Re: Public Variable Declaration

Post by cogier » Saturday 06th April 2019 11:39am

Following on from Stevedee's comments you can use this now. Just type: -

di [Tab]

You will get this ready for you to type a variable name
Dim iVar As Integer

Doctor Watson
Posts: 8
Joined: Wednesday 22nd August 2018 7:55am

Re: Public Variable Declaration

Post by Doctor Watson » Tuesday 09th April 2019 11:06am

Sorry for late reply. I was out of the country for afew days.
Thanks all, I'll see what I can do with it.

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