[Swarm-Support] why there is no answer?

[HU Xiaojun]

Hi,

I have a question.I posted it several days before, but got no answer.
I am wondering why.
I hope some one could give me a help.
I want to remove an object from a list and insert another object at the same
postion.

the code is:

- function
{
....
id  relationIndex;
id element;
id newelement=nil;
relationIndex = [relationList begin: [self getZone]];
for(element = [relationIndex next]; [relationIndex getLoc] == Member; element =
[relationIndex next])
{
     if(....)
         { 
[relationIndex remove];
newelement=....
         [relationIndex addAfter: newelement];
         }   
}
[relationIndex drop];
return self;
}

When I compile it, it complains that method "addAfter" not implemented by
protocol.
so I made some change,I decalre the relationIndex as:

id  relationIndex;
and keep the other things.

when i compile it, it complains that in the line of 
"relationIndex = [relationList begin: [self getZone]];" objects does not comform
to the "listindex" protocol.

Could somebody give me some advice?
The version is swarm-2.1.1.

Thanks!

xiaojun