[antlr-interest] Building Treenodes from Kleene Closure

[Dejas Ninethousand]

I think that's moving in the right direction, except I want the seperators
and not the expression.  I tried:

expression (e+=EXPRESSION_LIST_SEPARATOR expression)* -> $e+ EXPRESSION_LIST

which works fine unless there are 0 occurences of EXPRESSION_LIST_SEPARATOR
expression in which case the parser throws an early exit exception.  Is
there a way to exclude the $e+ if the number of occurrences is zero?

I tried:

expression_list
    :
    expression -> EXPRESSION_LIST
    |
    expression (e+=EXPRESSION_LIST_SEPARATOR expression)+ -> $e+
EXPRESSION_LIST

but ANTLER complains about introduction of left recursion (which I don't
see).



On Feb 19, 2008 11:37 AM, shmuel siegel <antlr at shmuelhome.mine.nu> wrote:

> Dejas Ninethousand wrote:
> > If I have the grammar:
> >
> >
> > expression_list
> >     :
> > expression (EXPRESSION_LIST_SEPARATOR expression)* -> EXPRESSION_LIST
> > ;
> >
> > Is there anyway to build the AST such that /n
> > /EXPRESSION_LIST_SEPARATOR nodes actually appear the number of times
> > the separator appears in the input?  If so, how would I express that
> > on the right hand side of the arrow?
> >
> >
> Am I not undertstanding your question? Will this do?
>
> expression_list
>    :
> e+=expression (EXPRESSION_LIST_SEPARATOR e+=expression)* ->
> ^(EXPRESSION_LIST $e+)
> ;
>
>
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