[antlr-interest] Re: ANTLR 3.0 question about common actions

[Monty Zukowski]

On Jul 28, 2004, at 6:22 PM, thrutchy wrote:

> Anyways, you might think about setting things up such that a
> syntax/rule/sub-rule is an object that is used to read/write/lookahead
> streams/trees.  If nothing else, it would make the generated code even
> more understandable.  But, I think it will open up other doors not
> thought of - like defining a rule that has a rule as an argument
> (because a rule is now an object that can be passed around). i.e.
>
> list[Syntax item, sep] ::= item ( sep item )*
>

Although ANTLR generates methods for each rule, those methods are 
highly interdependent because of lookahead.  That's why adding an 
alternative to one rule can lead to dozens of ambiguities in other 
rules that directly or indirectly call that rule.

 From what I gather, you are talking about having an interpreted parser 
built by building objects and connecting them.  To do that you will 
need to come up with a scheme so all the rules can be analyzed and have 
lookahead conditions stored in them.  Parser rules are not modular the 
way that object methods are.

Monty

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