Inheritance of bisonC ++ with polymorphic

Question

I am trying to build an AST from bison grammar. Bison correctly generates a parser, but when I try to parse a sample code with some mathematical operations, its following error:

[Fatal] calling `.get<Tag__::EXPR>()', but Tag INT is encountered.

After debugging, I notice that the problem is with the non-terminal exprwith the following work:

expr:
      ...
    | operator
      {
         $$ = $1;
      }

And operatorhas the following production:

operator:
   ...
| INTEGER
  {
    $$ = new ast::expression::IntASTNode(std::stoi(d_scanner.matched()));
  }

I use polymorphic semantic types, exprand operatormarked ones exprthat respond to ExprASTNodetype witch is the base class for IntASTNodewith a tag INT. I guess the bison gets the type from the tag and checks the tags before making any cast. Is there any way to resolve this?

Answer 1

:

operator:
     ...
        | INTEGER
          {
            $$(ast::expression::IntASTNode(std::stoi(d_scanner.matched())));
          }

bisonc++ static_cast $$ $$(expr). bison++.