[Swarm-Support] Re: Re: working with (indexed) lists: beginner's Q

[Jurgen van der Pol]

Paul,

Thanks. Partial success, but not quite. it works somewhat, but not as I 
would like.

In bug.m:

- (void) setMyCargoList: aList	// this gets its input from modelswarm.m 
-buildObject via [aBug setMyCargoList: cargoList];
{
        myCargoList = aList;    // the list in a bug variable
	myCargoIndex = [myCargoList begin: [self getZone]]; // the index in a 
bug variable
}

- setMyCargo
{
        Cargo *myCargo;                         // ok, pointer to a cargo object
	myCargo = [myCargoIndex next];	// or get, anyways bug variable gets 
input from(via?) the index
	xDest = [myCargo getXDest];		// x destination coordinates from cargo 
object
        yDest = [myCargo getYDest];             // ditto y destination
        credits = [myCargo getCargoValue];      // the value from the cargo 
object
}


This works a bit. In that the bugs at least get their three variables 
set with the data from the cargo object. However, due to

modelswarm.m
-buildObject
{
        ...
        [aBug setMyCargoList: cargoList];
        ...
}

during bug construction, each bug has the same local instance of the 
cargo list made in modelswarm. However, - setMyCargo in bug.m causes 
all bugs (assume 10 bugs, 10 cargo's) to get the same destination for 
each 'cycle' (bug #1 thru #10 get cargo #1's specifics like x,y 
destination), so they all head off to the same spot, then get the next 
one from the list (bug #1 thru #10 get cargo #2), all head to there 
etc. What I need is to have bug #1 to get cargo #1, bug #2 cargo #2 
etcetera. I'm not sure how to fix this (yet).

Ultimo, I want to have one global list with independent cargo movements 
on it (cargo appears, gets allocated to a truck, dies if not picked up, 
etc). The other independent bit are the bugs whom all should have have 
updatable (refresh) access to this constantly shifting cargo list 
entity, can bid on what's present, get some, do the chores and get back 
for more. So there is a model schedule issue here, but that's another 
question ;-)

> cargoIndex = [cargoList begin: [self getZone]]; //note, in Model swarm,
>                                             //use begin: self, in Bug,
>                                         //use this

Ok, thanks for pointing out the difference.


> Cargo * anObject;  //specific declaration for clarity
> for (anObject = [cargoIndex next]; [cargoIndex getLoc]==Member;
> anObject= [cargoIndex next])
> {
>     //do something to cargo objects
>
> }
> [cargoIndex drop];

It' still not clear to me from the documentation & examples what the 
specifics are for a list and for an index thereof. E.g. where does 
Member gome from?

> All the other stuff about making the changes show on the grid is really
> a separate problem.

Understood, that's not where the problem is anyways.

Thanks for the examples, they clarified some, but not all.

Ok, back to trail & error on a sunny North Sea coast tomorrow...

Cheers,
Jurgen.