Re: [Perl-widget-developer] Widget and templates - QED - stringify overloading

[<ja...@la...>]

On the subject of overloading - not overlording....

I made a sample where I have:

 Widget_Test ISA Widget_SuperTest ISA Widget_Base

The overload syntax that I showed below would go into Widget_Base

Try 1 - Widget_Base.pm has:
  use overload '""' => &display;

  This has the unfortunate consequence of binding to the Widget_Base::display method right off the bat. No good for subclasses.

Try 2 - Widget_Base.pm has:
  use overload '""' => "display";

  This allows for the object instance class to provide the method  and will follow ISA if not defined in calling class.

MAJOR BONUS FOR ALL
The performance difference between:
  print $widget->display [direct]
and 
  print $widget [overload]
is a whopping 30-35 times on my machine.

direct: 42 wallclock secs (42.48 usr +  0.00 sys = 42.48 CPU) @ 11770.24/s (n=500000)
overload:  1 wallclock secs ( 1.35 usr +  0.00 sys =  1.35 CPU) @ 370370.37/s (n=500000)

Wow, eh!

Jay

On Fri, 08 June 2001, Stephen Adkins wrote:

> 
> At 10:10 AM 6/8/2001 -0700, ja...@la... wrote:
> >There were a couple of good points about my proposed how to use widgets in
> Templating systems. I know the thought of changing a system like Template
> Toolkit is unattractive. In the long run I feel a few strategic changes
> could make all lives easier.
> >
> >HOWEVER - GET THIS:
> >
> >I thought to myself if we do something like:
> >  $widget=[ a widget instance ];
> >  print $widget;
> >
> >We get a lovely output like:
> >  Widget::HTML::Thinggy=HASH(0x80903040)
> >
> >Using the overload (perldoc overload) package we can simply overload the
> stringify operator to whatever we wish:
> >
> >Pacakge Widget::HTML::Thinggy;
> >
> >sub render_html {
> >}
> >
> >use overload '""' => \&render_html; # or *whatever*
> 
> Good idea.
> 
> >Now print $widget will actually call render_html to create what to print.
> Delicious.
> >
> >I can rip out the funky code I whacked into Template Toolkit and still
> just place my widget where I want, calling it by name and seeing its
> default rendering (HTML) in all its glory.
> >
> >We should look at putting this into the Widget::HTML::Base.pm package.
> >
> 
> Good idea.
> 
> >use overload '""' => \&render; # Does this inherit properly? Maybe not.
> Might need a bit of fancy footwork for subclasses to Widget::HTML::Base
> 
> Give this a try and let us know what works.
> 
> Stephen