// TokenClass enumeration definition
// TokenClass is an enumeration to represent lexical token classes in the 
// PL/0 programming language.

public enum TokenClass {
  EOF, 
  // keywords
  BEGIN, CALL, CONST, DO, END, IF, ODD, PROC, THEN, VAR, WHILE,
  // punctuation
  COMMA, PERIOD, SEMICOLON,
  // operators
  LPAREN, RPAREN, ASSIGN, PLUS, MINUS, TIMES, SLASH, EQ, LT, LE, GT, GE, NE,
  // ids and integers
  ID, INTEGER
}