Re: Implementing Frequency Lists.

[Paul E. Johnson]

"William S. Shu" wrote:
> 
> Please for assistance.  My problem can be abstractly described as follows:
> 
> I want to create a frequency list. 
> 

Benedikt S told me how to do this last year. 

First, create a new class, say called "Frequency_Indicator".  Iniside
there, create an instance variable
        int total;
And methods such as 
-addOne
{
total++;
return self;
}

-(int)getTotal
{
return total;
}

(Note I'm not using the word Count because it is used in the swarm
library and a method you might have, like, "getCount" could cause a
clash with the built in method in Lists, I recall).

Next, suppose you have N categories. Make a swarm array of N catetories:

    anArray=[Array create:  [self getZone] setCount:N];

(This is off the top of my head, so double check syntax in manual).
Then create N instances of the Frequency_Indicator Class, and put each
one into position in the Array.  Then when you want to augment the
Frequency_Indicator in position k, you get the k'th element of anArray
and tell that object to addOne, as in

    [[anArray atOffset: k] addOne];
And to retrieve that, you replace addOne with "getTotal". 

> My second question then is: How do I inherit (or acquire)
> existing/implemented methods of the List protocol?  In other words, how can
> I use existing/implemented protocols of swarm.
You can't subclass from the List protocols, you can only use them. If
you need enhancements, you have options, such as write a new class, of
type "SwarmObject", say, that has a list in it and then enhance that new
class to do what you want. 

> 
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> 
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-- 
Paul E. Johnson                         email: address@hidden
Dept. of Political Science              http://lark.cc.ukans.edu/~pauljohn
University of Kansas                    Office: (785) 864-9086
Lawrence, Kansas 66045                  FAX: (785) 864-5700

                  ==================================
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   to day usage of Swarm.  For list administration needs (esp.
   [un]subscribing), please send a message to <address@hidden>
   with "help" in the body of the message.