From aad9ce3bda23efbab03595868bda7fc6dc3e03bf Mon Sep 17 00:00:00 2001
From: Alasdair Armstrong
Date: Fri, 2 Mar 2018 14:24:00 +0000
Subject: Fix off-by-one error in OCaml for loop compilation

Fix for loop in interactive interpreter

Fixes #8
---
 src/interpreter.ml   | 17 +++++++++++++++++
 src/ocaml_backend.ml |  4 ++--
 2 files changed, 19 insertions(+), 2 deletions(-)

(limited to 'src')

diff --git a/src/interpreter.ml b/src/interpreter.ml
index e39c90f0..55dcbed0 100644
--- a/src/interpreter.ml
+++ b/src/interpreter.ml
@@ -516,6 +516,23 @@ let rec step (E_aux (e_aux, annot) as orig_exp) =
        | Right exp' -> wrap (E_try (exp', pexps))
      end
 
+  | E_for (id, exp_from, exp_to, exp_step, ord, body) when is_value exp_from && is_value exp_to && is_value exp_step ->
+     let v_from = value_of_exp exp_from in
+     let v_to = value_of_exp exp_to in
+     let v_step = value_of_exp exp_step in
+     begin match value_gt [v_from; v_to] with
+     | V_bool true -> wrap (E_lit (L_aux (L_unit, Parse_ast.Unknown)))
+     | V_bool false ->
+        wrap (E_block [subst id v_from body; E_aux (E_for (id, exp_of_value (value_add_int [v_from; v_step]), exp_to, exp_step, ord, body), annot)])
+     | _ -> assert false
+     end
+  | E_for (id, exp_from, exp_to, exp_step, ord, body) when is_value exp_to && is_value exp_step ->
+     step exp_from >>= fun exp_from' -> wrap (E_for (id, exp_from', exp_to, exp_step, ord, body))
+  | E_for (id, exp_from, exp_to, exp_step, ord, body) when is_value exp_step ->
+     step exp_to >>= fun exp_to' -> wrap (E_for (id, exp_from, exp_to', exp_step, ord, body))
+  | E_for (id, exp_from, exp_to, exp_step, ord, body) ->
+     step exp_step >>= fun exp_step' -> wrap (E_for (id, exp_from, exp_to, exp_step', ord, body))
+
   | E_sizeof _ | E_constraint _ -> assert false (* Must be re-written before interpreting *)
 
   | _ -> failwith ("Unimplemented " ^ string_of_exp orig_exp)
diff --git a/src/ocaml_backend.ml b/src/ocaml_backend.ml
index 22bb7de6..795b6300 100644
--- a/src/ocaml_backend.ml
+++ b/src/ocaml_backend.ml
@@ -273,8 +273,8 @@ let rec ocaml_exp ctx (E_aux (exp_aux, _) as exp) =
      in
      let loop_compare =
        match ord with
-       | Ord_aux (Ord_inc, _) -> string "Big_int.less"
-       | Ord_aux (Ord_dec, _) -> string "Big_int.greater"
+       | Ord_aux (Ord_inc, _) -> string "Big_int.less_equal"
+       | Ord_aux (Ord_dec, _) -> string "Big_int.greater_equal"
        | Ord_aux (Ord_var _, _) -> failwith "Cannot have variable loop order!"
      in
      let loop_body =
-- 
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