private void match(TokenType token)
{
if (lookahead.Type == token)
{
lookahead = enumerator.MoveNext() ? enumerator.Current : new Token(TokenType.Empty);
}
else throw new InvalidOperationException(String.Format("Failed to match on {0}", token));
}
public string Parse(IEnumerable<Token> tokens)
{
enumerator = tokens.GetEnumerator();
result = new StringBuilder();
if (enumerator.MoveNext())
{
lookahead = enumerator.Current;
expr();
}
return result.ToString();
}
private void output(Token token)
{
result.Append(token.Value.ToString());
}
private static bool isDigit(Token lookahead)
{
return lookahead.Type == TokenType.Digit;
}