[antlr-interest] Disregarding subrule ordering

[Royne Borrud]

Hi.
My goal is to parse a statement similar to this:

object name {
    optionalParam1
    param1
    param3
    param2
    optionalParam3
}

My problem is that while I do not want to enforce a specific ordering
of the parameters, I do want to make sure that all three parameters
occur once and only once, and that the optional parameters occur once
or not at all. Is this possible without adding specific code to handle
this? I'm beginning to think not... :/
If there isn't, has anyone got any hints for how to go about this?