examples/OCaml-Kaleidoscope/Chapter2/toplevel.ml

   1 (*===----------------------------------------------------------------------===
   2  * Top-Level parsing and JIT Driver
   3  *===----------------------------------------------------------------------===*)
   4
   5 (* top ::= definition | external | expression | ';' *)
   6 let rec main_loop stream =
   7   match Stream.peek stream with
   8   | None -> ()
   9
  10   (* ignore top-level semicolons. *)
  11   | Some (Token.Kwd ';') ->
  12       Stream.junk stream;
  13       main_loop stream
  14
  15   | Some token ->
  16       begin
  17         try match token with
  18         | Token.Def ->
  19             ignore(Parser.parse_definition stream);
  20             print_endline "parsed a function definition.";
  21         | Token.Extern ->
  22             ignore(Parser.parse_extern stream);
  23             print_endline "parsed an extern.";
  24         | _ ->
  25             (* Evaluate a top-level expression into an anonymous function. *)
  26             ignore(Parser.parse_toplevel stream);
  27             print_endline "parsed a top-level expr";
  28         with Stream.Error s ->
  29           (* Skip token for error recovery. *)
  30           Stream.junk stream;
  31           print_endline s;
  32       end;
  33       print_string "ready> "; flush stdout;
  34       main_loop stream