[Gambas-user] Global variables

[Stephen]

On 12/29/2015 12:14 PM, Tobias Boege wrote:
> On Tue, 29 Dec 2015, Stephen wrote:
>> Reading this, in addition to seeing the need for a "Wait", I thought the
>> following;
>>
>>     Does putting the desired global variable in a class mean the class
>> needs to be instantiated within the scope of the code example given? i.e.
>>
> Strictly speaking, yes.
>
>> PUBLIC GlobalVar as globalVars ' Change the name of the class to keep
>> the var name within the example unchanged.
>>
>> within the code of the form which contains the GObtn and exitBtn objects?
>>
>> The above would make GlobalVars.iexit visible to all classes outside of
>> the scope of where it was instantiated, so all forms in the project
>> could then see it.
>>
> Not really. If Form1 is the form where the Public declaration above is made,
> then another class would have to use Form1.GlobalVar.iexit to access the
> iexit variable. It cannot directly *see* the GlobalVar object.
    Yes, of course.
>> However this can be avoided if the variable "iexit" is declared in a
>> "module" as opposed to a "class". Doing this it instantly becomes global
>> within the scope of the project, requiring only the addition of the
>> "Wait" to process the exitBtn_Click() event and exit the loop.
>>
> I take it that your question is "why?".
   No, not at all. It was just a statement of fact, another way of doing it.

> You can think of a module as a class
> which has an implicit
>
>    Create Static
>
> statement in its header and where every symbol is implicitly Static. [ Note
> that you *can* instantiate a module using New, i.e. it is not implicitly
> Create Private, but you cannot do anything with an instance of a module
> because every symbol is static (accessing any symbol from the instance
> throws a "<class>.<symbol>  is static" error). ]
>
   Yes, exactly.

> Read about the Create Static statement here[0]. To explain my first comment
> above: You need to have an object of your global variables class available
> to use those variables. But employing Create Static you can basically make a
> class name (and class names are project-global) refer to an object (the
> automatic instance of that class). The result is that you have a globally
> accessible object.
   Yes. Is that not equivalent to using a module, albeit perhaps with 
more control.

> Regards,
> Tobi
>
> [0] http://gambaswiki.org/wiki/lang/createstatic
>


-- 
Kindest Regards
Stephen A. Bungay, Prop.
Smarts On Site Information Systems