/// If one of the current characters (or next non-whitespace character) is not the expected value, then an error is thrown
public IStringScanner ExpectChar(IEnumerable <char> characters)
{
AssertNotFinished();
CachePos();
AutoSkipWhitespace();
if (ExpectCharImpl(characters))
{
Match = NextChar.ToString();
Next(1);
NewPos();
}
else
{
ThrowUnexpectedCharacterException();
}
return(this);
}
/// <summary>
/// If current character (or next non-whitespace character) is not the expected value, then an error is thrown
/// </summary>
/// <param name="character"></param>
/// <returns></returns>
///
public IStringScanner ExpectChar(char character)
{
AssertNotFinished();
CachePos();
AutoSkipWhitespace();
if (NextChar == character)
{
Match = NextChar.ToString();
Next(1);
NewPos();
}
else
{
ThrowUnexpectedCharacterException();
}
return(this);
}
public string Advance()
{
var old = Token;
SkipSpaces();
if (!HasNext)
{
Token = null;
}
else
{
switch (NextChar)
{
case '"':
Position++;
var sb = new StringBuilder("\"");
bool escaped = false, done = false;
while (HasNext)
{
if (NextChar == '\\')
{
if (escaped)
{
sb.Append('\\');
}
else
{
escaped = true;
}
}
else if (escaped)
{
escaped = false;
switch (NextChar)
{
case 'n':
sb.Append("\n");
break;
case 'r':
sb.Append("\r");
break;
case 't':
sb.Append("\t");
break;
case '"':
sb.Append("\"");
break;
default:
throw new InvalidCharStringLiteralException();
}
}
else if (NextChar == '"')
{
Position++;
done = true;
break;
}
else
{
sb.Append(NextChar);
}
Position++;
}
Token = sb.ToString();
if (!done)
{
throw new InvalidCharStringLiteralException();
}
break;
case '\'':
Position++;
if (!HasNext)
{
throw new InvalidCharStringLiteralException();
}
Token = "'" + NextChar;
Position++;
if (!HasNext || NextChar != '\'')
{
throw new InvalidCharStringLiteralException();
}
Position++;
break;
default:
if (StandaloneChars.Contains(NextChar))
{
Token = NextChar.ToString();
Position++;
}
else if (char.IsLetter(NextChar) || NextChar == '_')
{
Token = TakeWhile(x => char.IsLetterOrDigit(x) || x == '_');
}
else if (char.IsNumber(NextChar))
{
Token = TakeWhile(char.IsNumber);
}
else if (IsSymbol(NextChar))
{
Token = TakeWhile(IsSymbol);
}
else
{
throw new IllegalCharacterException(NextChar);
}
break;
}
}
return(old);
}