[antlr-interest] Tree grammar for expression subrules?

[g4 at novadsp.com]

On 04/03/2011 19:13, Bart Kiers wrote:

>> I'd expect that to become the tree-grammar rule:
>>
>>     expression
>>        :  term
>>        |  ^(OR expression term)
>>        |  ^(OR expression EPSILON)
>>        ;

Hello Bart

Once again, extremely useful input. Thanks. My question though still 
stands. Cannot discern any pattern in writing the tree rules as, for 
example, this seems to violate cardinality ... or does it?