Re: Type-checking in bison, C++

Tim Converse (converse@cs.uchicago.edu) wrote:
: However, I doubt that a simple %union declaration,
: with some of the alternative types being my C++ classes,
: will let me compose classes using the bison type machinery.


  You just have to use pointers. For example ...


%{
  // Include your *.h here
%}


%union {
    AstExp *exp; /* For expressions */
    AstIntConst *ivalue; /* For integer constants */
    int iconst; /* For the integer constants of the lexer */
}




%type <exp> AddExp
%type <ivalue> Integer
%type <iconst> IntConst
%%




/* Some part of your grammar ....*/




AddExp : IntConst '+' IntConst { $$ = new AstAddExp (new AstIntConst ($1),
                                                                                                          new AstIntConst ($3));
                                                              }
              | IntConst { $$ = new AstIntConst ($1); }
              ;


/* Some other part of your grammar ....*/
%%


// C/C++ code




    In the example AstAddExp and AstIntConst are subclasses of AstExp. That
  way you can make simple assignments and the compiler won't complain about
  it.
    I hope that this can help you.




--
| Paulo Pinto, pjmlp@students.si.fct.unl.pt |
--

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