From fc6505de45b4db4d9d9ae3e4d2259352c402f8cb Mon Sep 17 00:00:00 2001
From: Son Ho
Date: Wed, 24 Nov 2021 11:34:02 +0100
Subject: Implement access_place

---
 src/Interpreter.ml | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

(limited to 'src/Interpreter.ml')

diff --git a/src/Interpreter.ml b/src/Interpreter.ml
index 66a8fbd1..851726c3 100644
--- a/src/Interpreter.ml
+++ b/src/Interpreter.ml
@@ -973,6 +973,27 @@ let rec access_projection (access : projection_access) (env : env)
                     Ok (env1, { res with updated = nv })
               else Error (FailSharedLoan bids)))
 
+(** Generic function to access (read/write) the value at a given place.
+
+    We return the value we read at the place and the (eventually) updated
+    environment, if we managed to access the place, or the precise reason
+    why we failed.
+ *)
+let access_place (access : projection_access) (env : env)
+    (* Function to (eventually) update the value we find *)
+      (update : typed_value -> typed_value) (p : place) (env : env) :
+    (env * typed_value) path_access_result =
+  (* Lookup the variable's value *)
+  let value = env_lookup_var_value env p.var_id in
+  (* Apply the projection *)
+  match access_projection access env update p.projection value with
+  | Error err -> Error err
+  | Ok (env1, res) ->
+      (* Update the value *)
+      let env2 = env_update_var_value env p.var_id res.updated in
+      (* Return *)
+      Ok (env2, res.read)
+
 (*
 (*
 TODO: loans
-- 
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