diff --git a/lib/relational_semantic_interpreter.ml b/lib/relational_semantic_interpreter.ml
index c7a64f3..78081de 100644
--- a/lib/relational_semantic_interpreter.ml
+++ b/lib/relational_semantic_interpreter.ml
@@ -40,14 +40,148 @@ struct
   @type value_logic = value_ground logic with show, gmap
   type value_injected = value_ground ilogic
 
-  @type list_map_ground = (data_ground * data_ground) List.ground with show, gmap
-  @type list_map_logic = (data_logic * data_logic) List.logic with show, gmap
-  type list_map_injected = (data_injected * data_injected) List.injected ilogic
+  @type env_ground = (data_ground * data_ground) List.ground with show, gmap
+  @type env_logic = (data_logic * data_logic) List.logic with show, gmap
+  type env_injected = (data_injected * data_injected) List.injected ilogic
 
   @type ('env, 'mem, 'last_mem, 'assignments) state_abs =  'env * 'mem * 'last_mem * 'assignments with show, gmap
   @type state_ground = (list_map_ground, value_ground List.ground, data_ground, data_ground List.ground) state_abs with show, gmap
   @type state_logic = (list_map_logic, value_logic List.logic, data_logic, data_logic List.logic) state_abs logic with show, gmap
-  type state_injected = (list_map_injected, value_injected List.injected, data_injected, data_injected List.injected) state_abs ilogic
+  type state_injected = (env_injected, value_injected List.injected, data_injected, data_injected List.injected) state_abs ilogic
 
   (* ocanren type 'a lst = Nil | Cons of 'a * 'a lst *)
+
+  let rec list_replace xs id value ys =
+    conde
+    [ (xs === Nil) (ys === Nil) (* TODO: error *)
+    ; fresh (x xs') (xs === x :: xs') (id === 0) (ys === value :: xs)
+    ; fresh (x xs' id' ys') (xs === x :: xs') (id === suc id') (ys === x :: ys')
+                            (list_replace xs' id' value ys')
+    ]
+
+  let env_get state id state' =
+    fresh (env env' mem mem_len assignments)
+    (state === (env, mem, mem_len, assignments))
+    (state' === (env', mem,  mem_len, assignments))
+    (List.assoc id env env')
+
+  let env_add state id mem_id state' =
+    fresh (env env' mem mem_len assignments)
+    (state === (env, mem, mem_len, assignments))
+    (state' === (env', mem,  mem_len, assignments))
+    (env' == (id, mem_id) :: env)
+
+  let inv_id mem_len id id' = (id === mem_len - id - 1)
+
+  (* --- *)
+
+  let mem_get state id value' =
+    (fresh mem mem_len)
+    (state === (_, mem, mem_len, _))
+    (fresh mem_len_inv)
+    (inv_id mem_len mem_len_inv)
+    (fresh mem_id)
+    (env_get state id mem_id)
+    (List.nth mem mem_len_inv mem_id value')
+
+  let mem_set state id value state'=
+    (fresh env mem mem_len assignments)
+    (state === (env, mem, mem_len, assignments))
+    (fresh mem_id) (env_get state id mem_id)
+    (fresh inv_mem_id) (inv_id mem_len mem_id inv_mem_id)
+    (fresh mem') (list_replace mem mem_id value mem')
+    (state' === (env, mem', mem_len, id :: assignments))
+
+  let mem_add state value state' =
+    (fresh env mem mem_len assignments)
+    (state === (env, mem, mem_len, assignments))
+    (fresh mem') (mem' === value :: mem)
+    (state' === (env, mem, suc mem_len, assignments))
+
+  let mem_check state id state' =
+    conde
+    [ (mem_get state id BotV) (state' === state) (* TODO: error *)
+    ; (mem_get state id UnitV) (state' === state)
+    ]
+
+  (* --- *)
+
+  let arg_to_value state arg value' =
+    conde
+    [ (arg === RValue) (value' === UnitV)
+    ; (fresh id) (arg === LValue id) (mem_get state id value')
+    ]
+
+  let st_mem_len state mem_len' = (state === (_, _, mem_len, _))
+
+  let st_add_arg state state_before id arg_tag arg state'' =
+    conde
+    [ (arg_tag === Ref) (arg === RValue) (state'' === state) (* TODO: error *) (* TODO: allow later ?? *)
+    ; (fresh arg') (arg_tag === Ref) (arg === LValue arg')
+      (fresh value') (env_get state_before arg value')
+                     (env_add state id value' state'')
+    ; (arg_tag === Value)
+      (fresh value' state' mem_len_dec')
+      (arg_to_value state_before arg value')
+      (mem_add state value' state')
+      (suc mem_len_dec' === st_mem_len state) (* or ... = ... - 1*)
+      (env_add state' id mem_len_dec' state'')
+    ]
+
+  let st_spoil_assignments state state' =
+    (fresh env mem mem' mem_len assignments)
+    (state === (env, mem, mem_len, assignments))
+    (List.fold_left (fun mem id -> list_replace mem (inv_id mem_len @@ env_get state id) BotV) mem assignments mem')
+    (state') === (env, mem', mem_len, [])
+
+  (* --- *)
+
+  let rec eval_stmt state prog stmt state' =
+    conde
+    [ (fresh f_id args)
+      (stmt === Call (f_id, args))
+      (fresh f args')
+      (List.nth prog f_id f)
+      (List.map (fun arg -> LValue arg) args args')
+      (* TODO how, rewrite from scratch ??? *)
+      (eval_fun state prog f args')
+    ; (fresh id) (stmt === Read id) (mem_check state id state')
+    ; (fresh id) (stmt === Write id) (mem_set state it UnitV state')
+    ]
+
+  and eval_body state prog body state' =
+    (List.fold_left (fun state stmt -> eval_stmt state prog stmt) state body)
+    (* TODO how, rewrite from scratch ??? *)
+
+  and eval_fun state prog decl args state' =
+    (fresh arg_tags body)
+    (fresh env_before mem_before len_before assignments_before)
+    (fresh state_clean)
+    (state_clean === ([], mem_before, len_before, []))
+    (fresh state_with_vars)
+    (state_with_vars === List.fold_left2 (fun (state, id) arg_tag arg -> (st_add_arg state state id arg_tag arg, id + 1)) (state, 0) arg_tags args)
+    (* TODO how, rewrite from scratch ??? *)
+    (fresh state_evaled)
+    (eval_body state prog body state_evaled)
+    (fresh state_spoiled)
+    (st_spoil_assignments state_evaled state_spoiled)
+    (fresh mem_updated len_to_drop)
+    (len_to_drop === len - len_before)
+    (List.drop len_to_drop mem mem_updated)
+    (state' === (env_before, mem_updated, len_before, assignments_before))
+
+  and eval_fun_empty_args state prog decl state' =
+    (fresh arg_tags)
+    (decl === (arg_tags, _))
+    (List.map (fun _ -> RValue) arg_tags args) (* TODO how, rewrite from scratch ??? *)
+    (eval_fun state prog decl args state')
+
+  (* --- *)
+
+  let empty_state state = (state === ([], [], 0, []))
+
+  let eval_prog all_prog state' =
+    (fresh prog main_decl)
+    (all_prog == (prog, main_decl))
+    (eval_fun_empty_args empty_state prog main_decl state')
 end
diff --git a/lib/semantic_interpreter.ml b/lib/semantic_interpreter.ml
index 2952dd8..a7cc3d0 100644
--- a/lib/semantic_interpreter.ml
+++ b/lib/semantic_interpreter.ml
@@ -23,13 +23,12 @@ struct
 
   (* --- static interpreter (no rec) --- *)
 
-  type env = (int * data) list
-
   (* TODO: allow data (rvalue) in calls ?? *)
   type arg = RValue | LValue of data
   type value = UnitV | BotV (* NOTE: RefV of data - not needed for now *)
 
-  (* TODO: replace env map with pairs *)
+  type env = (int * data) list
+
   (* env * memory * last unused memory * assignments *) 
   type state = env * value list * int * data list
 
@@ -74,8 +73,7 @@ struct
       | (Ref, RValue) -> raise @@ Ref_rvalue_argument id (* TODO: allow later ?? *) 
       | (Ref, LValue arg) -> env_add state id (env_get state_before arg)
       | (Value, arg) -> let state = mem_add state (arg_to_value state_before arg) in
-                        let state = env_add state id (st_mem_len state - 1) in
-                        state
+                        env_add state id (st_mem_len state - 1)
 
   let st_spoil_assignments state =
     match state with (env, mem, mem_len, assignments) ->
@@ -88,7 +86,8 @@ struct
       | Read id -> mem_check state id
       | Write id -> mem_set state id UnitV
 
-  and eval_body state prog body = List.fold_left (fun state stmt -> eval_stmt state prog stmt) state body
+  and eval_body state prog body =
+    List.fold_left (fun state stmt -> eval_stmt state prog stmt) state body
 
   and eval_fun state prog decl args =
     match decl with (arg_tags, body) ->