/// <summary>
/// Call the error handler.
/// </summary>
/// <param name="token">The token causing the error.</param>
private void Error(Token token)
{
EventHandler<ErrorEventArgs> handler = ErrorEventHandler;
if (handler != null)
{
handler(this, new ErrorEventArgs
{
Token = token,
Line = token.Line,
Column = token.Column
});
}
}
/// <summary>
/// Get the next token from the input string.
/// </summary>
private Token GetToken()
{
Token token;
scanner.ConsumeWhiteSpace();
if (Char.IsLetter(scanner.Ch))
{
string id = scanner.ReadIdentifier();
// TODO: Handle keywords a little better.
if (id == "if")
{
token = new Token(TokenType.If, scanner.Line, scanner.Column);
}
else if (id == "else")
{
token = new Token(TokenType.Else, scanner.Line, scanner.Column);
}
else
{
token = new Token(TokenType.Id, scanner.Line, scanner.Column, id);
}
}
else if (Char.IsDigit(scanner.Ch))
{
token = new Token(TokenType.Num, scanner.Line, scanner.Column, scanner.ReadNumber());
}
else
{
switch (scanner.Ch)
{
case '\0':
token = new Token(TokenType.Eof, scanner.Line, scanner.Column);
break;
case '{':
token = new Token(TokenType.LBrace, scanner.Line, scanner.Column);
break;
case '}':
token = new Token(TokenType.RBrace, scanner.Line, scanner.Column);
break;
case '(':
token = new Token(TokenType.LParen, scanner.Line, scanner.Column);
break;
case ')':
token = new Token(TokenType.RParen, scanner.Line, scanner.Column);
break;
case ',':
token = new Token(TokenType.Comma, scanner.Line, scanner.Column);
break;
case ';':
token = new Token(TokenType.Semicolon, scanner.Line, scanner.Column);
break;
default:
token = new Token(TokenType.Unknown, scanner.Line, scanner.Column);
Error(token);
break;
}
scanner.Next();
}
return token;
}
