[antlr-interest] nesting rules, getting rule text

[Robin Debreuil]

Hi again, two hopefully easy questions (that is - hard for me, easy for you
: ).

1) I can't seem to figure out how to nest rules... I'm using a hetrogeneous
tree, and would like rules like (DOT identifier)* to nest. So something
like:

ruleA
 : ruleB (DOT! ruleB)*
 ;

becomes the tree:

AST_B
     |
     AST_B
              |
              AST_B

Maybe it would be easier to explain right by posting the type of thing I've
been trying, something like:

ruleA!
 :   r1:ruleB
  ( r2:ruleB {#r1 = #(#r1, #r2);} )*
 {#ruleA = #r1;}
 ;

which nests, but turns a.b.c into #(a, c). I'm doing this in the parser, not
the tree walker.


2) When getting the text of a rule, I've been calling the generated
variables directly (xx_AST), as in:

ruleA!
 : id:identifier STAR!
  { #ruleA =    #( [Ident, id_AST.getText()] ); } // eg. "id_AST"
 ;

Is there a better way to do that? Ident in this case is a user defined AST
token if that makes a difference, as in:
tokens
{
    Ident      <AST=DDW.CSharp.Ident>;
}


Thanks for the help again : ). The C# parser is all running and put into
trees, but the trees need a lot of work in the expression area - like array
declarations etc. I'm kind of not getting some of the required syntax there
I'm afraid...

Cheers, and thanks as always : )
Robin







 
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