C++ parsetree_t::drawepsilon方法代码示例

void parser_t::Statement(){
  parsetree.push(NT_Statement);
switch(scanner.next_token())
  {
  case T_eof:
    parsetree.drawepsilon();
    break;
  case T_m:
    cerr<<"m";
    Assignment();
    break;
  case T_label:
    cerr<<"L";
    Label();
    break;
  case T_goto:
    cerr<<"goto";
    Jump();
    break;
  case T_print:
    cerr<<"printf()";
    Print();
    break;
  default:
    syntax_error(NT_Statement);
    break;
  }
 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();
}

//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();
}

//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);

	fprintf(stderr, "int main()\n");
	fprintf(stderr, "{\n");
	fprintf(stderr, "\tint m[101];\n");
	fprintf(stderr, "\n");


	switch( scanner.next_token() )
	{
		case T_label:
		case T_goto:
		case T_m:
		case T_print:
			Statements();
			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();
	fprintf(stderr, "}\n");
}

void parser_t::LabelStatements()
{
	parsetree.push(NT_LabelStatements);

	switch(scanner.next_token())
	{
		case T_m:
		case T_print:
			LabelStatement();
			LabelStatements();
			break;
		case T_goto:
		case T_label:
		case T_eof:
			parsetree.drawepsilon();
			break;
		default:
			syntax_error(NT_LabelStatement);
			break;
	}


	parsetree.pop();

}

void parser_t::Statements()
{
  parsetree.push(NT_Statements);
  if(scanner.next_token() != T_eof){
    Statement();
    Statements();
  }
  else
    parsetree.drawepsilon();
  parsetree.pop();
}

void parser_t::Expression1(){
  parsetree.push(NT_Expression1);

//WRITEME: you will need to put the rest of the procedures here

  switch(scanner.next_token()){
  case T_eof:
    parsetree.drawepsilon();
    //eat_token(T_eof);
    break;
  case T_plus:
    //cerr<<"+";
    eat_token(T_plus);
    T();
    Expression1();
    break;
  case T_minus:
    //cerr<<"-";
     eat_token(T_minus);
     T();
     Expression1();
     break;
  case T_label:
    parsetree.drawepsilon();
    break;
  case T_goto:
    parsetree.drawepsilon();
    break;
  case T_if:
    parsetree.drawepsilon();
    break;
  case T_m:
    parsetree.drawepsilon();
    break;
  case T_print:
    parsetree.drawepsilon();
    break;
  case T_closesquare:
    parsetree.drawepsilon();
    break;
  case T_closeparen:
    parsetree.drawepsilon();
    break;
  default:
    syntax_error(NT_Expression1);
    break;

  }
  parsetree.pop();
}

void parser_t::furuImouto(string& expString)
{
	parsetree.push(NT_MultDivImouto);
	switch(scanner.next_token())
	{
	case T_times:
		eat_token(T_times);
		expString += "*";
		exp(expString);
		furuImouto(expString);
		break;
	case T_divide:
		eat_token(T_divide);
		expString += "/";
		exp(expString);
		furuImouto(expString);
		break;
	case T_eof:
			parsetree.drawepsilon();
			break;
	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_MultDivImouto);
		break;
	}

	parsetree.pop();
}

//WRITEME: you will need to put the rest of the procedures here
void parser_t::Statements()
{
    token_type watch = scanner.next_token();
    parsetree.push(NT_Statements);
    if((watch == T_label) || (watch == T_goto) || (watch == T_m)||(watch == T_print)){
        Statement();
        Statements();
    }else if(watch == T_eof){
        parsetree.drawepsilon();
    }else{
        syntax_error(NT_Statements);
    }
    parsetree.pop();
}

void parser_t::StatementsPrime()
{
  parsetree.push(NT_StatementsPrime);
  switch(scanner.next_token())
    {
    case T_eof:
      parsetree.drawepsilon();
      break;
    default:
      Statement();
      StatementsPrime();
    }
  parsetree.pop();
}

void parser_t::ExpressionP()
{
	//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_ExpressionPrime);

	switch( scanner.next_token() ) 
	{
		case T_label:
			parsetree.drawepsilon();
			break;
		case T_goto:
			parsetree.drawepsilon();
			break;
		case T_print:
			parsetree.drawepsilon();
			break;
		case T_m:
			parsetree.drawepsilon();
			break;
		case T_closeparen:
			parsetree.drawepsilon();
			break;
		case T_closesquare:
			parsetree.drawepsilon();
			break;
		case T_plus:
			eat_token(T_plus);
			cerr << "+";
			Term();
			ExpressionP();
			break;
		case T_minus:
			eat_token(T_minus);
			cerr << "-";
			Term();
			ExpressionP();
			break;
		case T_eof:
			parsetree.drawepsilon();
			break;
		default:
			syntax_error(NT_ExpressionPrime);
			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::JumpIf(){
  parsetree.push(NT_JumpIf);
  if(scanner.next_token() == T_if){
    code_printf("if(");
    eat_token(T_if);
    Expression();
    code_printf(")\n\t\t");
  }
  else
    parsetree.drawepsilon();
  

  parsetree.pop();

}

void parser_t::Power(){
  parsetree.push(NT_Power);
  switch(scanner.next_token()){
  case T_power:
    code_printf(", ");
    eat_token(T_power);
    Factor();
    code_printf(")");

    break;
  default:
    code_printf(", 1)");
    parsetree.drawepsilon();
  }
  parsetree.pop();

}

void parser_t::Statement()
{
	//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_Statement);
	switch( scanner.next_token() ) 
	{
		case T_m:
			eat_token(T_m);
			Assignment();
			break;

		case T_label:
			Label();
			//eat_token(T_label);

			scanner.next_token();
			break;

		case T_goto:
			//eat_token(T_goto);
			Jump();
			scanner.next_token();
			break;

//COME BACK TO FIX WHAT PRINT prints out ~!~!~!~!~!~!~!~!~!~!~!~!~!~~!!~~!!~!
		case T_print:
			//eat_token(T_print);
			Print();
			scanner.next_token();
			break;
		case T_eof:
			parsetree.drawepsilon();
			break;
		default:
			syntax_error(NT_Statement);
			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
	//scanner.next_token();
	parsetree.pop();
}

void parser_t::RTerm(){
  parsetree.push(NT_RTerm);
  switch(scanner.next_token()){
  case T_times:
    code_printf(" * ");
    eat_token(T_times);
    Term();
    break;
  case T_divide:
    code_printf(" / ");
    eat_token(T_divide);
    Term();
    break;
  default:
    parsetree.drawepsilon();  
  }
  parsetree.pop();
}