private void expect(TokenType type)
{
if (lookahead.TokenType != type)
throw new SyntaxException (String.Format ("Expected {0}, got {1} ", type, lookahead.TokenType));
lookahead = lexer.GetNextToken ();
}
public Token GetNextToken()
{
Token nextToken;
RemoveBlanks ();
if (sourceString.Length == 0) {
nextToken = new Token (TokenType.EOF);
} else {
sourceString = Matcher.Match (sourceString, out nextToken);
}
return nextToken;
}
public static string Match(string str, out Token nextToken)
{
nextToken = null;
for (var i = 0; i < matches.Length; i++) {
if (matches [i].Match (str)) {
nextToken = new Token (matches [i].Type);
return str.Substring (matches [i].Length);
}
}
// Controllo se si tratta di un id char (char|digit) ...
if (Char.IsLetter (str [0])) {
var i = 1;
while (i < str.Length && Char.IsLetterOrDigit (str [i])) {
i++;
}
var word = str.Substring (0, i);
for (i = 0; i < reservedWords.Length; i++) {
if (reservedWords [i].Equals (word))
nextToken = new Token (reservedWords [i].Type);
}
if (nextToken == null)
nextToken = new Token (word, TokenType.ID);
return str.Substring (word.Length);
} else if (str [0] == '"') {
var i = 1;
while (str [i] != '"') {
i++;
}
nextToken = new Token (str.Substring (1, i - 1), TokenType.ID);
return str.Substring (i + 1);
} else
throw new InvalidInputString ();
}
public Parser(String str)
{
lexer = new Scanner (str);
lookahead = lexer.GetNextToken ();
}