[antlr-interest] Parsing optional component in Tree Walker

[John D. Mitchell]

>>>>> "Peter" == Peter Kronenberg <PKronenberg at technicacorp.com> writes:
[...]

> I have a tree walker that needs to deal with an optional component C.

Another alternative is to not make it optional.  I.e, when you build the
tree, if the real C isn't there, create an imaginary token/node for it.

Basically, this is the NullObject pattern.

Take care,
	John