On Thursday 06 September 2001 03:38 pm, david at aminal.com wrote:

> So, I guess my question is , how do I make my Node instance known to
> the rest of the Smalltalk environment by its unique identifier? Is it
> possible to create global variables on-the-fly?
>
> In a workspace it seems so simple,
>
> uniqueID1 := Node new.
> uniqueID2 := Node new.
>
> etc.
>
> But I don't see how to do this in a 'new' method, where the variable name
> is generated and then pointed at the resulting instance.

The usual way to do this would be to have a class variable that is a 
Dictionary of the mappings between names and instances. If you make this a 
WeakValueDictionary, you don't have to worry about deleting members (Nodes is 
a class variable):

Node class>>initialize
      Nodes ifNil: [ Nodes := WeakValueDictionary new ].

So in Node new, you'd register the new instance with the Node class:

Node class>>new
       | newNode |
       newNode := super new initialize.
       Nodes at: newNode id put: newNode.

Node class can then have a lookup method :

Node class>>named: anID
    Nodes at: anID ifAbsent: [].

-- 
Ned Konz
currently: Stanwood, WA
email:     ned at bike-nomad.com
homepage:  http://bike-nomad.com