Beispiel #1
0
 public Token scan()
 {
     for (; ; peek = (char)Console.Read())
     {
         if (peek == ' ' || peek == '\t')
         {
             continue;
         }
         else if (peek == '\n')
         {
             ++line;
         }
         else
         {
             break;
         }
     }
     if (Char.IsDigit(peek))
     {
         int v = 0;
         do
         {
             v = 10 * v + int.Parse(peek.ToString()); //this is dumb is there a better way?
             peek = (char)Console.Read();
         } while (Char.IsDigit(peek));
         return new IntegerToken(v);
     }
     if (Char.IsLetter(peek))
     {
         string wordValue = "";
         do
         {
             wordValue += peek;
             peek = (char)Console.Read();
         } while (Char.IsLetterOrDigit(peek));
         if (words.ContainsKey(wordValue))
         {
             return words[wordValue];
         }
         else
         {
             Word w = new Word(Tag.IDENTIFIER, wordValue);
             words[wordValue] = w;
             return w;
         }
     }
     Token t = new Token(peek);
     peek = ' ';
     return t;
 }
Beispiel #2
0
 protected virtual Token BuildToken()
 {
     if (EndOfSource())
     {
         return null;
     }
     if (Char.IsDigit(peek))
     {
         return Integer();
     }
     if (Char.IsLetter(peek))
     {
         return Word();
     }
     Token t = new Token(peek);
     peek = ' ';
     return t;
 }