internal virtual bool TryReadCharacterLiteral(ILookaroundEnumerator <char> enumerator, [NotNullWhen(true)] out Token?token)
{
token = default;
var escaped = false;
if (enumerator.Current != '\'')
{
return(false);
}
enumerator.MoveNext(); //Eat the quote.
if (enumerator.TryGetNext(out var nextChar) == false)
{
throw new LexingException(ExpressionParserStrings.ResourceManager.GetString("LexerError_NewlineInConstant", CultureInfo.InvariantCulture));
}
if (enumerator.Current == '\'')
{
throw new LexingException(ExpressionParserStrings.ResourceManager.GetString("LexerError_EmptyCharacterLiteral", CultureInfo.InvariantCulture));
}
if (enumerator.Current == '\\')
{
if (nextChar.IsValidEscapedChar() == false)
{
throw new LexingException(ExpressionParserStrings.ResourceManager.GetString("LexerError_UnrecognizedEscape", CultureInfo.InvariantCulture));
}
enumerator.MoveNext(); // Pass the backslash
escaped = true;
}
if (enumerator.TryGetNext(out nextChar) == false)
{
throw new LexingException(ExpressionParserStrings.ResourceManager.GetString("LexerError_NewlineInConstant", CultureInfo.InvariantCulture));
}
if (nextChar != '\'')
{
throw new LexingException(ExpressionParserStrings.ResourceManager.GetString("LexerError_TooManyCharsInCharLiteral", CultureInfo.InvariantCulture));
}
token = new Token(TokenType.CharacterLiteral, null, escaped ? enumerator.Current.Escape() : enumerator.Current);
enumerator.MoveNext(); //Move to quote
return(true);
}
