[antlr-interest] Nested Closures -> Nested AST Generation
Randall R Schulz
rschulz at sonic.net
Sat Jul 7 11:08:27 PDT 2007
On Saturday 07 July 2007 10:55, Johannes Luber wrote:
> Randall R Schulz wrote:
> > Hi,
> > Here is a fragment of a AST-generating grammar I have:
> > atom
> > : ( '('
> > predicate = term
> > '('
> > RoleSet ( '(' role = name arg = term ')' ) *
> > ')'
> > ')'
> > )
> > -> ^( RoleSet $predicate ^( RoleArg $role $arg ) * )
> > ;
> > I've discovered (through the miracle of DOTTreeGenerator!) that no
> > matter how many repetitions of the ( role=name arg=term ) tuples
> > appear following the RoleSet token, only one RoleArg subtree is
> > present in the synthesized AST. That single RoleArg subtree's
> > values always correspond to the last repetition of the RoleSet
> > tuples that was present in the input.
> > Am I doing this wrong, or is this a bug?
> Try "RoleSet ( '(' role+=name arg+=term ')' ) *".
Great, thanks, that works. I had a work-around, but it was not quite as
clean as this (it took an auxiliary production).
> Best regards,
> Johannes Luber
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