Re: [Perl-widget-developer] Structure of Widget Base classes

[Gunther B. <gu...@ex...>]

At 12:26 AM 6/7/2001 +0200, Issac Goldstand wrote:
> >
> > I have a concern with the current structure of the base
> > classes.  Currently the way I see it, the structure is as follows
> >
> > Widget::Base - base class for all widgets
> > Widget::HTML::Base - base class for all HTML widgets (inherits
>Widget::Base)
> > Widget::HTML::Select - a widget class (inherits from Widget::HTML::Base)
> >
> > Now if we add WML we would get the following extra classes
> >
> > Widget::WML::Base - base class for all HTML widgets (inherits
>Widget::Base)
> > Widget::WML::Select - a widget class (inherits from Widget::HTML::Base)
> >
> >
> > My concern here is that there is no sharing of code between
> > Widget::HTML::Select and Widget::WML::Select besides the Widget::Base and
> > Widget::HTML::Base.  I think there should be a base class for Select
> > widgets that the HTML and WML Select widgets can inherit from.  Otherwise
> > we will be duplicating a tonne of code between the different interfaces.
> >
> >
> > Essentially, I think we have our Base class structure backwards.  What we
> > need to think about is what similarities and differences there will be
> > between the different interfaces.  The only method that should be
> > different in a Widget is the method that renders the actual widget.
> > Everything else will most likely be the same.
> >
> > To fit a Widget::Select baseclass into the current structure would require
> > multiple inheritance, and I don't know if that is such a good idea.
> >
> >
> > What if we used the following structure:
> >
> > Widget::Base - base class for all widgets
> > Widget::Select - a generic dropdown box widget (inherits from
>Widget::Base)
> >
> > Widget::HTML::Base - a base class for HTML widgets (doesn't inherit)
> > Widget::HTML::Select - a display class for Select box
> > (inherits from Widget::HTML::Base)
> >
> > The Widget::Select object can instantiate the correct display object from
> > one of the interfaces once it knows (from the config file) which interface
> > we are displaying to. It can choose to use Widget::HTML::Select or
> > Widget::WML::Select depending on the requirements.
> >
> >
> > Does anyone have any other ideas or comments on the implications of this?
> > I haven't thought this out completely yet, but I wanted to throw it out
> > before we got too deep into the coding.
>
>This is pretty much what I've been ranting about for the past week or so - I
>belive that we should have something like:
>
>Widget::Object (base class)
>Widget::Object::Select (pseudo-code for select - contains 'template'
>instructions for rendering code and any other internals needed)
>
>Widget::Renderer (base class for renderer [is this needed?  I'm not quite
>sure yet])
>Widget::Renderer::HTML (class to render pseudo-code to HTML/JavaScript)
>Widget::Renderer::WML (class to render pseud-code to WML/WMLScript [or
>whatever OpenWave's calling their scripting language])
>
>The programer should select a Renderer object by tying it into the
>controller when constructing
>(eg. my $wc=new Widget(-options.... -renderer=>"Widget::Renderer::HTML");  )
>
>   Issac

I quite like this distinction between widget helper classes (in object) and 
the ones that are meant to be directly renderable.