RE: Protocol questions

[Murali Nandula]

Following is a work around..

Recruiter:
-(int) doThis
{
 printf("Error: superclass/interface method! \n")
 exit(0);
 return 0; // to satisfy the compiler
}

Type A:
- (int) doThis
{
 // sub class
 // do calculations 
 return <somenumber>;
}

Since TypeA overrides the Recruiter the appropriate method
is called from sub-class always. Ofcourse if you tried to
send the call to TypeB which doesnot override it will
throw error and exit!

-Murali

> -----Original Message-----
> From: Paul Johnson [mailto:address@hidden
> Sent: Friday, April 07, 2000 11:48 AM
> To: Swarm-support
> Subject: Protocol questions
> 
> 
> In a model, the inheritance structure is like this:
> 
>                  Recruiter
>                       |
>                       |
>                ___________
>               |           |
>                typeA       typeB
> 
> To improve compile-time error checking, I declared a protocol
> "Recruiter" and both typeA and typeB adopt it, as in.
> 
> @interface typeA: Recruiter <Recruiter>
> 
> Here are my problems.
> 
> 1. Suppose typeA and typeB do really different things for a method
> "doThis".  I want the Recruiter object to be able to use that 
> method to
> get something, say:
> 
>       value=[self doThis];
> 
> So it gets whatever is appropriate for whatever type it is.
> 
> In the Recruiter class, what do I put as the return of a method like
> this:
> -(int) doThis
> {
>        [self subclassResponsibility: @selector(doThis)];
>       return ???????;
> }
>  
> 2. In the Recruiter class, many methods are implemented.  Some methods
> are added in typeA that are not in typeB. When I have a typeA 
> object, I
> want to use those methods, but programs won't compile.  The compiler
> says the method is not in the protocol.  I have to add these 
> methods to
> the protocol to get the compiler to work.  
> 
> 
> -- 
> 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
> 
>                   ==================================
>    Swarm-Support is for discussion of the technical details of the day
>    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.
> 

                  ==================================
   Swarm-Support is for discussion of the technical details of the day
   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.