examples/OCaml-Kaleidoscope/Chapter3/toplevel.ml

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