[antlr-interest] Handling delimeter separated lists

[Jason]

Hello,

I have a grammar which has multiple instances of
comma-separated lists of different types.  The upshot
of this is that I've got several sets of rules which
look like this:

foo_list: foo (COMMA foo)*;

I find these lists much harder to process than their
LR counterparts.  I'm generally doing something like
this:

foo_list
  returns [List fooInstList]
  :
{ String fooInst = null; fooInstList = null; } 
:
  fooInst = foo[true, null] 
  {
    fooInstList = new ArrayList( );
    fooInstList.add(fooInst);
  }
  (EAL_COMMA property[false, fooInstList])*
  {
    // Nothing left to do
  }
}
;

foo [boolean isFirst, List foobarList] returns [String
fooInst]
  {fooInst = null;} 
  :
  foo:FOOBAR
  {
    String fooInst = foo.getText( );
    if (!isFirst)
    {
      foobarList.add(fooInst);
    }
  }
;

This seems to work but it seems less than elegant
especially in those cases where foo is called from
productions other than foo_list.  This issue must
arise pretty frequently in LL grammars.  Does anyone
have any idioms they'd like to share?  Is there
something I'm missing?  Thanks in advance.

-jason  

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