// sless.gr
// example of scannerless operation in Elkhound

context_class Scannerless : public UserActions {
public:
};

terminals {
   0: CHAR_EOF;
  10: CHAR_NEWLINE;
  32: CHAR_SPACE;
  40: CHAR_LPAREN      "(";
  41: CHAR_RPAREN      ")";
  97: CHAR_A           "a";
 102: CHAR_F           "f";
 105: CHAR_I           "i";
}

nonterm Start {
  -> WS Prog;
}

nonterm Prog {
  -> empty;
  -> Prog IDENT;
  -> Prog IF Prog FI;
  -> Prog LPAREN Prog RPAREN;
}

nonterm Ident {
  fun maximal() {}          // use maximal munch disambiguation
  -> "f";
  -> "i";
  -> "f" Ident;
  -> "i" Ident;
  subsets If, Fi;           // prefer keywords to identifiers
}

// keywords
nonterm If -> "i" "f";
nonterm Fi -> "f" "i";

// tokens, with whitespace following
nonterm IDENT -> Ident WS;
nonterm IF -> If WS;
nonterm FI -> Fi WS;
nonterm LPAREN -> "(" WS;
nonterm RPAREN -> ")" WS;

// whitespace
nonterm WS {
  -> empty;
  -> CHAR_SPACE WS;
  -> CHAR_NEWLINE WS;
}