open Camlp4.PreCast ;

module G = Camlp4.PreCast.Gram ;

value exp = G.Entry.mk "exp" ;

value prog = G.Entry.mk "prog" ;

EXTEND G

exp:

[ "apply"

  [ e1 = SELF; e2 = exp LEVEL "simple" ->

    let p = Loc.dump in

    let () =

    Format.eprintf "e1:    %a,@.e2:    %a,@.e1-e2: %a,@._loc:  %a@."

      p e1 p e2 p (Loc.merge e1 e2) p _loc

    in

    _loc

  ]

| "simple"

  [ _ = LIDENT -> _loc ]

];

prog: [[ e = exp; `EOI -> e ]];

END ;

(* and the following function: *)

value parse_string entry s =

try

  G.parse_string entry (Loc.mk "<string>") s

with [ Loc.Exc_located loc exn ->

begin

  print_endline (Loc.to_string loc);

  print_endline (Printexc.to_string exn);

  failwith "Syntax Error"

end ] ;

parse_string prog "f x";