chainTo: and chainUnlinkLast

[Keith Hodges]

Lukas Renggli wrote:
> Hi Keith,
>
>   
>> your rewrite of MAChainAccessor provoked some panic here!
>>     
>
> sorry, I didn't expect that anybody was using those.
>
> I think with the refactoring they became more useful, especially since  
> you don't need to know anymore about the details. You can now just write
>
> 	aDescription accessor: #foo
>
> and it will automatically create the appropriate accessor object for  
> you. The same for
>
> 	aDescription accessor: #(foo bar)
>
> will chain #foo to #bar.
>
>   
>> Just to let you know that I had written a couple of chaining and
>> unchaining operaterations, which I use for mapping a flat db query  
>> into a magritte model. It allows me to treat a chain accessor as a  
>> kind of stack as the model is traversed.
>>     
>
> I don't know if that is useful in general? If you think so, please  
> feel free to add it to Magritte-Core. I saw that you use it to build a  
> stack. Wouldn't it be much simpler if you just kept the selectors in  
> an OrderedCollection and sent #asAccessor if required?
>   
I have to say that this is a very bumpy migration! I have over 900 
existing instances and the new implementation is reversing the instVars. 
At present I am attempting to reverse them by hand but it is tricky.

Keith