[Gambas-user] About class and components

[Olivier Coquet]

Thank's Tobias, I've read all :)

A misunderstood for me, why statics var are not accessible after 
instancing the class ?

regards

Olivier

Le 02/02/2021 à 12:50, Tobias Boege a écrit :
> On Tue, 02 Feb 2021, Olivier Coquet wrote:
>> Auto-Reply.
>>
>> First:
>>
>> Public cmp_comp As Component = Component.Load("component name")
>>
>> Second:
>>
>> CLASS *Classe_in_component*
>>
>> third:
>>
>> Public MyClass as *Classe_in_component*
>>
>> "Et voila".
>>
> There is another way using introspection. Once you loaded the component,
> its classes will be registered in the global symbol table (of classes).
> You can also obtain Class objects (not the Class syntax keyword that you
> used before) from the Classes class:
>
>    ' Will find the class once its component is loaded
>    Dim hClass As Class = Classes["Classe_in_component"]
>
> You cannot use this to declare variables using Public or Dim but those
> need a compile-time class name, but you can use this Class object to
> create new objects of that class nevertheless, at runtime:
>
>    Dim hObj As Object = hClass.New([ any arguments go here ])
>
> Just type your new object as an Object. Gambas will still resolve method
> calls and property accesses dynamically, even if hObj does not have the
> static type Classe_in_component.
>
> See the wiki [1] for what else you can do with a Class object.
>
> For plugins, what is better depends at least on whether:
>
>    - there is a specific singular functionality that you put into a
>      plugin because it is optional and would introduce a dependency
>      that you don't want to put on everybody (e.g. your coffee machine
>      gets an email notification plugin which requires the expensive
>      filters with SMTP support), or
>
>    - you have multiple plugins for the same functionality (e.g.
>      audio codecs) that expose the same interface but where many
>      can be loaded concurrently.
>
> In the first case, all the class names should be fixed and I think it
> would be more convenient to work with your first solution of forward-
> declaring the class at compile time.
>
> In the latter case, I would use introspection and keep interface Class
> objects around in a Collection of (audio) plugins over which you can
> iterate and ask each plugin if it knows what to do with a given file.
>
> Best,
> Tobias
>
> [1] http://gambaswiki.org/wiki/comp/gb/class
>