//проверка типа лексемы
private void CheckLexType(Lex lex, LexTypes type)
{
if (lex.Type != type)
{
throw new Exception(SyntaxisErrorMessage(lex, type));
}
}
public static string LexTypesToString(LexTypes lexTypes)
{
if (lexTypes < (LexTypes)256 && lexTypes > 0)
{
return(string.Format("{0}", (char)lexTypes));
}
return(lexTypes.ToString());
}
// Получем следующую лексему.
private void GetToken()
{
tokType = LexTypes.NONE;
token = "";
// Конец выражения. Опускаем пробел
if (expIdx == exp.Length)
{
return;
}
while (expIdx < exp.Length && char.IsWhiteSpace(exp[expIdx]))
{
++expIdx;
}
// Хвостовой пробел завершает выражение.
if (expIdx == exp.Length)
{
return;
}
if (IsDelim(exp[expIdx]))
{
token += exp[expIdx];
expIdx++;
tokType = LexTypes.DELIMITER;
}
else if (char.IsDigit(exp[expIdx]))
{
// Это число?
while (!IsDelim(exp[expIdx]))
{
token += exp[expIdx];
expIdx++;
if (expIdx >= exp.Length)
{
break;
}
}
tokType = LexTypes.NUMBER;
}
}
public void Match(LexTypes type)
{
if (TokenType != type)
{
var expectedName = Enum.GetName(typeof(LexTypes), type);
if (string.IsNullOrEmpty(expectedName))
{
expectedName = string.Format("{0}", ((char)type));
}
var foundName = Enum.GetName(typeof(LexTypes), TokenType);
if (string.IsNullOrEmpty(foundName))
{
foundName = string.Format("{0}", (char)TokenType);
}
throw new ScriptException(string.Format("Unexpected token type. Expected {0}, found {1}. Line: {2}, Col: {3}", expectedName, foundName, LineNumber, ColumnNumber));
}
GetNextToken();
}
public void Match(LexTypes type)
{
if (TokenType != type)
{
String expectedName = Enum.GetName(typeof(LexTypes), type);
if (String.IsNullOrEmpty(expectedName))
{
expectedName = String.Format("{0}", ((char)type));
}
String foundName = Enum.GetName(typeof(LexTypes), TokenType);
if (String.IsNullOrEmpty(foundName))
{
foundName = String.Format("{0}", ((char)TokenType));
}
throw new ScriptException(String.Format("Unexpected token type. Expected {0}, found {1}", expectedName, foundName));
}
GetNextToken();
}
//построение сообщения о ошибке
private string SyntaxisErrorMessage(Lex lex, LexTypes expect)
{
return($"Syntaxis error in line {lex.LineNo}.\n"
+ "Expected " + expect.ToString() + ", but get "
+ lex.Type.ToString() + ".");
}