// Token.java
// used to compute next token
// ; used as a line delimiter

public class Token {
  int pos ;
  
  public Token() {
    pos = 0;
  }

  public String getNextToken (String input) {
    int i = pos;
    
    if (input.length() == 0)
      return "(null)";
    
    while (i < input.length() &&
           input.charAt (i) != ' ' &&
           input.charAt (i) != ';')
      i++;
    
    if (i+1 <= input.length()) {
      String token = new String (input.substring (pos, i));
      pos = i + 1;
      return token;
    }
    else {
      pos = input.length();
      return "(null)";
    }
  }
}