/*scanner.h
  Definitions for scanner.cc for the WFF language.
  Copyright (c) 1998 by Matthew Belmonte.*/

enum TokenType {
    /* ATOMS */
  IdentifierToken,	/*a one-character identifier name, 'A'..'Z'*/
    /* UNARY OPERATOR */
  NotToken,		/* ~ */
    /* BINARY OPERATORS */
  AndToken,		/* & */
  OrToken,		/* | */
  ImpliesToken,		/* => */
  EquivToken,		/* = */
    /* LEXICAL GOODIES */
  LeftParenToken,	/* ( */
  RightParenToken,	/* ) */
  PeriodToken,		/* . */
  };

/*data abstractors for tokens*/
class Token
  {
  public:
    Token();                            /*default constructor*/
    Token(TokenType);                   /*non-identifier token*/
    Token(char);                        /*identifier token with specified val.*/
    TokenType type;
    char identifier;                    /*value of identifier*/
    void next();                        /*gets next token from input*/
    void print();                       /*prints contents of node*/
  private:
    void make_token(TokenType);
    void letter_start();
    void symbol_start();
  };

void init_scanner();