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

[Cees H. <ce...@si...>]

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.


-- 
Cees Hek