[antlr-interest] On trees and JavaBeans, part 2: tree creation

[Terence Parr]

Hi Guys,

I like the flexibility of swing's tree interface, but I don't like the 
need to pass in the parent to get the child.

Tree t = tree.getChild(parent, i);

just seems less pleasant than

Tree t = parent.getChild(i);

Also, you still need a tree node of some kind to actually implement a 
tree.  Perhaps Tree and TreeNode?

I'm open to suggestions still because the payload model requires an 
extra node just to wrap the pointer (as an "adaptor") to another kind 
of tree node.  For example, if you have a DOM tree or something that 
doesn't directly satisfy the Tree interface, you must essentially make 
a duplicate, parallel tree that points node-for-node from the ANTLR 
tree into the DOM tree.

The main issue for me is: when do you really want to walk a "foreign" 
(non-ANTLR constructor) tree?  It happens sometimes, but usually 
because you're building your own trees with actions, which you could 
make implement the Tree interface easily.  It would be fairly rare 
don't you think to want to walk a totally unrelated data structure?

The payload thing works GREAT in most cases as it just points at the 
associated token :)

Ter