C++ parsetree_t类代码示例

void parser_t::statement()
{
	parsetree.push(NT_Statement);
	switch(scanner.next_token())
	{
	case T_label:
		label();
		break;
	case T_goto:
		jump();
		outSave += ";\n";
		break;
	case T_m:
		assignments();
		outSave += ";\n";
		break;
	case T_print:
		print();
		outSave += ";\n";
		break;
	default:
			syntax_error(NT_Statement);
			break;
	}
	
	parsetree.pop();
}

void parser_t::Assignment(){

	parsetree.push(NT_Assignment);

	switch( scanner.next_token() ) 
	{
		case T_opensquare:
			cerr<<"m";
			eat_token(T_opensquare);
			cerr<<"[ ";
			Expression();
			scanner.next_token();
			eat_token(T_closesquare);
			cerr<<" ] ";
			scanner.next_token();
			eat_token(T_equals);
			cerr<<" = ";
			Expression();
			cerr<<"; \n";
			scanner.next_token();
			break;

		// case T_eof:
		// 	parsetree.drawepsilon();
		// 	break;
		default:
			syntax_error(NT_Assignment);
			break;
	}

	//now that we are done with List, we can pop it from the data
	//stucture that is tracking it for drawing the parse tree
	parsetree.pop();

}

void parser_t::TermP(){

	parsetree.push(NT_TermP);

	switch( scanner.next_token() ) 
	{
		case T_times:
			eat_token(T_times);
			cerr<<" * ";
			Factor();
			TermP();
			break;

		case T_divide:
			eat_token(T_divide);
			cerr<<" / ";
			Factor();
			TermP();
			break;

		case T_eof:
			parsetree.drawepsilon();
			break;

		default:
			parsetree.drawepsilon();
			// syntax_error(NT_ExpressionP);
			break;
	}

	//now that we are done with List, we can pop it from the data
	//stucture that is tracking it for drawing the parse tree
	parsetree.pop();

}

// Jump_ -> "if" Expression | epsilon
void parser_t::Jump_(std::string label_name)
{
	std::string exp;
	parsetree.push(NT_Jump_);
	switch(scanner.next_token()) {
		case T_if:
			// conditional jump
			eat_token(T_if);
			exp = Expression();
			fprintf(stderr, "\tif (%s) goto label%s;", exp.c_str(), label_name.c_str());
			break;
		case T_m:
		case T_label:
		case T_goto:
		case T_equals:
		case T_print:
		case T_eof:
			fprintf(stderr, "\tgoto label%s;", label_name.c_str());
			parsetree.drawepsilon();
			// From follow set
			break;
		default:
			syntax_error(NT_Jump_);
	}

	parsetree.pop();
}

void parser_t::MoreStatement(){
	parsetree.push(NT_MoreStatement);

	switch(scanner.next_token()){

		case T_label:
		case T_m:
		case T_goto:
		case T_print: 
			Statement();
			MoreStatement();
			break;


		case T_eof:
			parsetree.drawepsilon();
			break;

		default:
			syntax_error(NT_MoreStatement);
			break;

	}

	parsetree.pop();

}

//Here is an example
void parser_t::Start()
{
  //push this non-terminal onto the parse tree.
  //the parsetree class is just for drawing the finished
  //parse tree, and should in should have no effect the actual
  //parsing of the data
  parsetree.push(NT_Start);

  switch( scanner.next_token() ) 
    {
    case T_plus:
      eat_token(T_plus);
      Start();
      break;
    case T_eof:
      parsetree.drawepsilon();
      break;
    default:
      syntax_error(NT_Start);
      break;
    }

  //now that we are done with List, we can pop it from the data
  //stucture that is tracking it for drawing the parse tree
  parsetree.pop();
}

void parser_t::Statements()
{
	//push this non-terminal onto the parse tree.
	//the parsetree class is just for drawing the finished
	//parse tree, and should in should have no effect the actual
	//parsing of the data
	parsetree.push(NT_Statements);

	bool thereIsMore = true;
		switch( scanner.next_token() )
		{
			case T_label:
			case T_goto:
			case T_m:
			case T_print:
				Statement();
				Statements();
				break;
			case T_eof:
				thereIsMore = false;
				break;
			default:
				syntax_error(NT_Statements);
				break;
		}

	//now that we are done with List, we can pop it from the data
	//stucture that is tracking it for drawing the parse tree
	parsetree.pop();
}

void parser_t::Factor()
{
	//push this non-terminal onto the parse tree.
	//the parsetree class is just for drawing the finished
	//parse tree, and should in should have no effect the actual
	//parsing of the data
	parsetree.push(NT_Factor);

	switch( scanner.next_token() ) 
	{
		case T_num:
			eat_token(T_num);
			if(scanner.next_token()==T_power)
			{
				powBuffer=scanner.numberList[numberListSpot];
			}
			else
				cerr << scanner.numberList[numberListSpot];
			numberListSpot++;
			break;
		case T_m:
			eat_token(T_m);
			cerr << "m";
			if (scanner.next_token() == T_opensquare)
			{
				eat_token(T_opensquare);
				cerr << "[";
				Expression();
				if(scanner.next_token() == T_closesquare)
				{
					eat_token(T_closesquare);
					cerr << "]";
				}
				else
					syntax_error(NT_Factor);
			}
			else
				syntax_error(NT_Factor);
			break;
		case T_openparen:
			eat_token(T_openparen);
			cerr << "(";
			Expression();
			if (scanner.next_token() == T_closeparen)
			{
				eat_token(T_closeparen);
				cerr << ")";
			}
			else
				syntax_error(NT_Factor);
			break;
		default:
			syntax_error(NT_Factor);
			break;
	}

	//now that we are done with List, we can pop it from the data
	//stucture that is tracking it for drawing the parse tree
	parsetree.pop();
}

void parser_t::Jump()
{
	//push this non-terminal onto the parse tree.
	//the parsetree class is just for drawing the finished
	//parse tree, and should in should have no effect the actual
	//parsing of the data
	parsetree.push(NT_Jump);

	if(scanner.next_token() == T_goto)
	{
		eat_token(T_goto);
		if(scanner.next_token() == T_num)
		{
			eat_token(T_num);
			int labelNum = scanner.numberList[numberListSpot];
			numberListSpot++;
			JumpP(labelNum);
		}
		else
			syntax_error(NT_Jump);

	}
	else
		syntax_error(NT_Jump);

	//now that we are done with List, we can pop it from the data
	//stucture that is tracking it for drawing the parse tree
	parsetree.pop();
}

void parser_t::numend(string& expString)
{
	parsetree.push(NT_NumEnd);
	switch(scanner.next_token())
	{
	case T_openparen:
		//cout <<"here";
		eat_token(T_openparen);
		expString += "(";
		//cout<< "ga";
		expString += expression();
		//cout <<"wtfffff";
		eat_token(T_closeparen);
		expString += ")";
		break;
	case T_m:
		eat_token(T_m);
		eat_token(T_opensquare);
		expString += "m[";
		expString += expression();
		eat_token(T_closesquare);
		expString += "]";
		break;
	case T_num:
		//cout <<"num found";
		eat_token(T_num);
		expString += scanner.numString();
		break;
	default:
			syntax_error(NT_NumEnd);
			break;
	}
	parsetree.pop();
}

void parser_t::Power()
{
	//push this non-terminal onto the parse tree.
	//the parsetree class is just for drawing the finished
	//parse tree, and should in should have no effect the actual
	//parsing of the data
	parsetree.push(NT_Power);

	switch( scanner.next_token() ) 
	{
		case T_num:
			Factor();
			PowerP();
			break;
		case T_m:
			Factor();
			PowerP();
			break;
		case T_openparen:
			Factor();
			PowerP();
			break;
		default:
			syntax_error(NT_Power);
			break;
	}

	//now that we are done with List, we can pop it from the data
	//stucture that is tracking it for drawing the parse tree
	parsetree.pop();
}

bool parser_t::expImouto(string& expString)
{
	parsetree.push(NT_Exp);
	bool rr = false;
	switch(scanner.next_token())
	{
	case T_power:
		eat_token(T_power);
		expString += ",";
		numend(expString);
		expString += ")";
		rr = true;
		break;
	case T_eof:
			parsetree.drawepsilon();
			break;
	case T_times:
	case T_divide:
	case T_plus:
	case T_minus:
	case T_closeparen:
	case T_closesquare:
	case T_label:
	case T_goto:
	case T_m:
	case T_print:
		parsetree.drawepsilon();
		break;
	default:
		syntax_error(NT_Exp);
		break;
	}
	parsetree.pop();
	return rr;
}

void parser_t::expressionImouto(string& expString)
{
	parsetree.push(NT_ExpressionImouto);
	switch(scanner.next_token())
	{
	case T_plus:
		eat_token(T_plus);
		expString += "+";
		furu(expString);
		expressionImouto(expString);
		break;
	case T_minus:
		eat_token(T_minus);
		expString += "-";
		furu(expString);
		expressionImouto(expString);
		break;
	case T_eof:
			parsetree.drawepsilon();
			break;
	case T_closeparen:
	case T_closesquare:
	case T_label:
	case T_goto:
	case T_m:
	case T_print:
		parsetree.drawepsilon();
		break;
	default:
		syntax_error(NT_ExpressionImouto);
	}
	parsetree.pop();
}

void parser_t::jumpImouto()
{
	parsetree.push(NT_JumpImouto);
	switch(scanner.next_token())
	{
	case T_if:
		eat_token(T_if);
		outSave += "if(";
		outSave += expression();
		outSave += ")";
		break;
	case T_eof:
		parsetree.drawepsilon();
		break;
	case T_label:
	case T_goto:
	case T_m:
	case T_print:
		break;
	default:
		syntax_error(NT_JumpImouto);
		break;
	}
	parsetree.pop();
}

int parser_t::Rel(int v)
{
	parsetree.push(NT_Rel);
	switch( scanner.next_token() )
	{
		case T_num:
			v = RelP(Expr(v));
			break;
		case T_lt:
			eat_token(T_lt);
			if (v < Expr(v)) v = 1;
			else v = 0;
			break;
		case T_gt:
			eat_token(T_gt);
			if (v > Expr(v)) v = 1;
			else v = 0;
			break;
		case T_eq:
			eat_token(T_eq);
			if (v == Expr(v)) v = 1;
			else v = 0;
			break;
		case T_openparen:
			v = RelP(Expr(v));
			break;
		default:
			syntax_error(NT_Rel);
			break;
	}
	parsetree.pop();
	return v;
}