anchor.diff:  
   attr_variable_name
       :   NAME_NAME ATTR_EQ ATTR_VALUE_START t=NAME ATTR_VALUE_END
  -        -> VARIABLENAME[$t, ($t.text)->chars]
  +        -> VARIABLENAME[$t, newVarString($t.text).c_str()]
       ;
   
   attr_type_name
  
positive.code: }
  
  @parser::members {
      // converts varname into a string formatted as a variable name
      // (lower_case_with_underscores)
      std::string newVarString(pANTLR3_STRING varname) {
  
negative.code:                 i++;
              }
          }
          // strip trailing underscores (from trailing blanks)
          boost::trim_right_if(buf, boost::is_any_of("_"));
          return buf;
      }
  }
  