Scanner MathParser.cc

AST::NodeT MathParser::parse_binary_operation(bool B_allow_args, int precedence_level) {
    struct AST::Symbol* associativity;
    bool B_visible_operator, B_unary_operator = false;
    //printf("level is %d, input is: %s\n", precedence_level, input_value->str().c_str());
    if(operator_precedence_list->empty_P(precedence_level))
        return(B_allow_args ? parse_application() : parse_value());
    /* special case for unary - */
    AST::NodeT result = (precedence_level == operator_precedence_list->minus_level && input_value == Symbols::Sdash) ? (B_unary_operator = true, Symbols::Szero) : parse_binary_operation(B_allow_args, operator_precedence_list->next_precedence_level(precedence_level));
    if(AST::NodeT actual_token = operator_precedence_list->match_operator(precedence_level, input_value, /*out*/associativity, /*out*/B_visible_operator)) {
        while(actual_token && actual_token != Symbols::SlessEOFgreater) {
            AST::NodeT operator_ = B_visible_operator ? consume() : Symbols::Sspace;
            if(input_value == Symbols::Srightparen || input_value == Symbols::Sautorightparen) { // premature end.
                if(!B_visible_operator)
                    raise_error("<operand>", ")");
                return(B_unary_operator ? operator_ : makeApplication(operator_, result)); /* default to the binary operator */
            }
            AST::NodeT b = parse_binary_operation(B_allow_args, associativity != Symbols::Sright ? operator_precedence_list->next_precedence_level(precedence_level) : precedence_level);
            if(B_unary_operator && !b) // -nil
                return(operator_);
            result = operation(operator_, result, b);
            /* for right associative operations, the recursion will have consumed all the operators on that level and by virtue of that, the while loop will always stop after one iteration. */
            if(associativity == Symbols::Snone)
                break;
            actual_token = operator_precedence_list->match_operator(precedence_level, input_value, /*out*/associativity, /*out*/B_visible_operator);
        }
        return(result);
    } else
        return(result);
}