****SPAM(7.4)**** Re: ****SPAM(11.2)**** [Tutor] Larger program organization

[Kent Johnson]

Bob Gailer wrote:
> At 03:21 PM 2/12/2005, Brian van den Broek wrote:
> [snip]
>  > I am curious about Bob's "Whenever you find yourself writing
>  > an if statement ask whether this would be better handled by subclasses."
> 
> class A:
> ...
> class A1(A);
>   def foo(self, ...):
>     statements to process object of type 1
> class A2(A);
>   def foo(self, ...):
>     statements to process object of type 2
> 
> That takes less code. Eliminates the type property. I get greater 
> visibility about the existence and distinction of the two (or more) 
> sub-types. I now can much more easily extend each subtype.

Also you can more easily *add* a new subtype. Using if statements, if you add a new type you have to 
find all the relevant conditionals and add another condition. With subclassing, you create a new 
subclass and define the necessary methods. The changes are localized to the subclass and much easier 
to figure out.

Kent