/// <summary>
/// 2. declaration-list → declaration-list declaration | declaration
/// </summary>
/// <returns></returns>
TreeNode DeclarationList()
{
TreeNode program = null;
TreeNode last = null;
TreeNode temp = null;
currentToken = GetNextToken();
while (!CheckCurrentToken(TokenType.EOF))
{
if (!CheckCurrentToken(TokenType.INT) &&
!CheckCurrentToken(TokenType.VOID) && !CheckCurrentToken(';'))
{
ErrorRecord(ParseErrorType.InvalidType);
ConsumeUntil(";", "}");
//错误处理
//scan->add_err();
//sprintf(msg_temp, "Syntax error: invalid type \'%s\'",
// cToken.str.c_str());
//outputMsg(scan->lineno(), msg_temp);
//consumeUntil(SEMI, RBRACE); // ';', '}'
}
else if ((temp = Declaration()) != null)
{
if (program == null)
{
program = temp;
last = temp.LastSibling();
}
else
{
last.Sibling = temp;
last = temp.LastSibling();
}
}
currentToken = GetNextToken();
}
return(program);
}
/// <summary>
/// 10. compound-stmt → { local-declarations statement-list }
/// </summary>
/// <returns></returns>
TreeNode CompoundStmt()
{
TreeNode first = null;
TreeNode last = null;
TreeNode temp = null;
bool noBraces = false;
if (!Match(Convert.ToInt32('{')))
{// match "{"
noBraces = true;
--currentTokenIndex;
}
// local-declarations
while (true)
{
typeToken = currentToken = GetNextToken();
if (CheckCurrentToken(TokenType.INT) ||
CheckCurrentToken(TokenType.VOID))
{
temp = LocalDeclarations();
}
else
{
--currentTokenIndex;
break;
}
if (noBraces)
{
return(temp);
}
if (temp != null)
{
if (first == null)
{
first = temp;
last = temp.LastSibling();
}
else
{
last.Sibling = temp;
last = temp.LastSibling();
}
}
}
//currentToken = GetNextToken();
currentToken = GetNextToken();
while (true)
{
temp = null;
if (CheckCurrentToken('}'))
{
if (noBraces)
{
//错误处理
ErrorRecord(ParseErrorType.UnpairedRBrace);
}
break;
}
if (CheckCurrentToken(TokenType.EOF))
{
//错误处理
ErrorRecord(ParseErrorType.MissingRBraceBeforeEOF);
--currentTokenIndex;
break;
}
switch (currentToken.TokenTypes)
{
case (Int32)TokenType.READ:
temp = ReadStmt();
break;
case (Int32)TokenType.WRITE:
temp = WriteStmt();
break;
case (Int32)(';'):
case (Int32)TokenType.NUMBER:
case (Int32)('('):
temp = ExpressionStmt();
break;
case (Int32)TokenType.ID:
temp = SubcompoundStmt();
break;
case (Int32)TokenType.IF:
temp = IfStmt();
// currentToken = GetNextToken();
break;
case (Int32)TokenType.WHILE:
temp = WhileStmt();
break;
case (Int32)TokenType.RETURN:
temp = ReturnStmt();
break;
case (Int32)TokenType.ELSE:
//错误处理
ErrorRecord(ParseErrorType.UnpairedElseStatement);
ConsumeUntil(";", "}");
//scan->add_err();
//outputMsg(scan->lineno(), " unpaired \'else\' statement");
//consumeUntil(SEMI, RBRACE);
break;
default:
//错误处理
ErrorRecord(ParseErrorType.UndefinedSymbol);
ConsumeUntil(";", "}");
//scan->add_err();
//sprintf(msg_temp, "Syntax error: undefined symbol \"%s\"", cToken.str.c_str());
//outputMsg(scan->lineno(), msg_temp);
//consumeUntil(SEMI, RBRACE);
break;
}
if (noBraces)
{
return(temp);//// no braces
}
if (temp != null)
{
if (first == null)
{
first = temp;
last = temp.LastSibling();
}
else
{
last.Sibling = temp;
last = temp.LastSibling();
}
}
currentToken = GetNextToken();
}
return(first);
}