// Jump -> "goto" number Jump_
void parser_t::Jump()
{
parsetree.push(NT_Jump);
eat_token(T_goto);
char* label_name = scanner.scan_num();
eat_token(T_num);
Jump_(label_name);
parsetree.pop();
}
void parser_t::Label()
{
parsetree.push(NT_Label);
eat_token(T_label);
char* label_name = scanner.scan_num();
eat_token(T_num);
eat_token(T_colon);
fprintf(stderr, "\tlabel%s:", label_name);
parsetree.pop();
}
std::string parser_t::Expression()
{
std::string firstExpression("");
std::string result("");
std::ostringstream stream;
parsetree.push(NT_Expression);
switch (scanner.next_token()) {
case T_openparen:
eat_token(T_openparen);
firstExpression = Expression();
if (scanner.next_token() != T_closeparen) syntax_error(NT_Expression);
eat_token(T_closeparen);
stream << "(" << firstExpression << ")";
result = stream.str();
break;
case T_m:
eat_token(T_m);
if (scanner.next_token() != T_opensquare) syntax_error(NT_Expression);
eat_token(T_opensquare);
firstExpression = Expression();
if (scanner.next_token() != T_closesquare) syntax_error(NT_Expression);
eat_token(T_closesquare);
stream << "m[" << firstExpression << "]";
result = stream.str();
break;
case T_num:
result = scanner.scan_num();
eat_token(T_num);
break;
default:
syntax_error(NT_Expression);
break;
}
result = Expression_(result);
parsetree.pop();
return result;
}