defineVar_:
    identifier
    {
        // define an identifier in the symbol table 
        // initializing it to 0, return a SemVal holding its type and index

        $$ = d_symtab.defineVar(d_type, $1);            // define the var.
    }
;

defineVar:
    defineVar_
|
    defineVar_ '=' syntaxExpression expression
    {
        $$ = defineVar($1, $4);                     // define and keep the
                                                    // global var. init. code
    }
;



