[antlr-interest] Re: Heterogeneous AST - simple calculator pa rser

[koud0002]

The problem is with the heterogeneous AST construction.
If I use the default AST the grammar works as expected.
However, when I add the parser option:
  ASTLabelType = "CalcAST";

the tokens definition:
tokens {
  UNARY_MINUS<AST=UnaryMinusNode>;

  PLUS<AST=PlusNode>;
  MINUS<AST=MinusNode>;
  STAR<AST=MultNode>;
  DIV<AST=DivNode>;
  INT<AST=IntNode>;
}

and call the following methods on a parser object:
      parser.setASTNodeType("CalcAST");
      parser.setASTNodeClass("CalcAST");
it breaks.

I get: "unexpected end of subtree" error when tree-walking the 
expression: (- 8) + 7 * 2

Expression: -1 does not yield this error but still gives incorrect 
result of 1.

What do I need to do to get my hetorogeneous AST working properly.
Robert






 

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