diff --git a/simplest_model/analyzer.ml b/simplest_model/analyzer.ml
index e0a9c1e..2480d75 100644
--- a/simplest_model/analyzer.ml
+++ b/simplest_model/analyzer.ml
@@ -37,59 +37,61 @@ struct
    | ([], _) -> raise Not_found
 
 
-  let env_get state id = match state with
+  let env_get (state : state) (id : data) : data = match state with
     (env, _mem, _mem_len, _assignments) -> List.assoc id env
 
-  let env_add state id mem_id = match state with
+  let env_add (state : state) (id : data) (mem_id : data) : state = match state with
     (env, mem, mem_len, assignments) -> let env = (id, mem_id) :: env in
                                         (env, mem, mem_len, assignments)
 
-  let inv_id mem_len id = mem_len - id - 1
+  let inv_id (mem_len : int) (id : data) : data = mem_len - id - 1
 
-  let mem_get state id = match state with
+  let mem_get (state : state) (id : data) : value = match state with
     (_env, mem, mem_len, _assignments) -> List.nth mem @@ inv_id mem_len @@ env_get state id
 
-  let mem_set state id value= match state with
+  let mem_set (state : state) (id : data) (value : value) : state = match state with
     (env, mem, mem_len, assignments) -> let mem_id = inv_id mem_len @@ env_get state id in
                                         let mem = list_replace mem mem_id value in (env, mem, mem_len, id :: assignments)
 
-  let mem_add state value = match state with
+  let mem_add (state : state) (value : value) : state = match state with
     (env, mem, mem_len, assignments) -> let mem = value :: mem in (env, mem, mem_len + 1, assignments)
 
-  let mem_check state id = if mem_get state id == BotV then raise @@ Incorrect_memory_access id else state
+  let mem_check (state : state) (id : data) : state =
+    if mem_get state id == BotV then raise @@ Incorrect_memory_access id else state
 
 
-  let arg_to_value state arg = match arg with
+  let arg_to_value (state : state) (arg : arg) : value = match arg with
     | RValue -> UnitV
     | LValue id -> mem_get state id
 
-  let st_mem_len state =
+  let st_mem_len (state : state) : int =
     match state with (_, _, mem_len, _) -> mem_len
 
-  let st_add_arg state state_before id arg_tag arg =
+  let st_add_arg (state : state) (state_before : state)
+      (id : data) (arg_tag : tag) (arg : arg) : state =
     match (arg_tag, arg) with
       | (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
                         env_add state id (st_mem_len state - 1)
 
-  let st_spoil_assignments state =
+  let st_spoil_assignments (state : state) : state =
     match state with (env, mem, mem_len, assignments) ->
     (* TODO: use env var ids instead of mem_ids ?? *)
     (env, List.fold_left (fun mem id -> list_replace mem (inv_id mem_len @@ env_get state id) BotV) mem assignments, mem_len, [])
 
   let list_drop n xs = List.of_seq @@ Seq.drop n @@ List.to_seq xs
 
-  let rec eval_stmt state prog stmt =
+  let rec eval_stmt (state : state) (prog : fun_decl list) (stmt : stmt) : state =
     match stmt with
       | Call (f_id, args) -> eval_fun state prog (List.nth prog f_id) (List.map (fun arg -> LValue arg) args)
       | Read id -> mem_check state id
       | Write id -> mem_set state id UnitV
 
-  and eval_body state prog body =
+  and eval_body (state : state) (prog : fun_decl list) (body : body) : state =
     List.fold_left (fun state stmt -> eval_stmt state prog stmt) state body
 
-  and eval_fun state prog decl args =
+  and eval_fun (state : state) (prog : fun_decl list) (decl : fun_decl) (args : arg list) : state =
     match decl with (arg_tags, body) ->
     match state with (env_before, mem_before, len_before, assignments_before) as state_before ->
     let state = ([], mem_before, len_before, []) in
@@ -99,14 +101,14 @@ struct
     match state with (_env, mem, len, _assignments) ->
     (env_before, list_drop (len - len_before) mem, len_before, assignments_before) (* TODO: save some assignments ?? *)
 
-  and eval_fun_empty_args state prog decl =
+  and eval_fun_empty_args (state : state) (prog : fun_decl list) (decl : fun_decl) : state =
     match decl with (arg_tags, _) ->
     let args = List.map (fun _ -> RValue) arg_tags in
     eval_fun state prog decl args
 
-  let empty_state = ([], [], 0, [])
+  let empty_state : state = ([], [], 0, [])
 
-  let eval_prog (prog, main_decl) = ignore @@ eval_fun_empty_args empty_state prog main_decl
+  let eval_prog ((prog, main_decl) : prog) = ignore @@ eval_fun_empty_args empty_state prog main_decl
 
   (* tests *)
 
diff --git a/simplest_model_with_mods/analyzer.ml b/simplest_model_with_mods/analyzer.ml
index e0a9c1e..fd774f4 100644
--- a/simplest_model_with_mods/analyzer.ml
+++ b/simplest_model_with_mods/analyzer.ml
@@ -6,6 +6,7 @@ struct
   type data = int
 
   type tag = Ref | Value
+  type mode = Const | Mut (* TODO: add mode to func decl *)
   type stmt = Call of data * data list | Read of data | Write of data
 
   type body = stmt list
@@ -37,59 +38,61 @@ struct
    | ([], _) -> raise Not_found
 
 
-  let env_get state id = match state with
+  let env_get (state : state) (id : data) : data = match state with
     (env, _mem, _mem_len, _assignments) -> List.assoc id env
 
-  let env_add state id mem_id = match state with
+  let env_add (state : state) (id : data) (mem_id : data) : state = match state with
     (env, mem, mem_len, assignments) -> let env = (id, mem_id) :: env in
                                         (env, mem, mem_len, assignments)
 
-  let inv_id mem_len id = mem_len - id - 1
+  let inv_id (mem_len : int) (id : data) : data = mem_len - id - 1
 
-  let mem_get state id = match state with
+  let mem_get (state : state) (id : data) : value = match state with
     (_env, mem, mem_len, _assignments) -> List.nth mem @@ inv_id mem_len @@ env_get state id
 
-  let mem_set state id value= match state with
+  let mem_set (state : state) (id : data) (value : value) : state = match state with
     (env, mem, mem_len, assignments) -> let mem_id = inv_id mem_len @@ env_get state id in
                                         let mem = list_replace mem mem_id value in (env, mem, mem_len, id :: assignments)
 
-  let mem_add state value = match state with
+  let mem_add (state : state) (value : value) : state = match state with
     (env, mem, mem_len, assignments) -> let mem = value :: mem in (env, mem, mem_len + 1, assignments)
 
-  let mem_check state id = if mem_get state id == BotV then raise @@ Incorrect_memory_access id else state
+  let mem_check (state : state) (id : data) : state =
+    if mem_get state id == BotV then raise @@ Incorrect_memory_access id else state
 
 
-  let arg_to_value state arg = match arg with
+  let arg_to_value (state : state) (arg : arg) : value = match arg with
     | RValue -> UnitV
     | LValue id -> mem_get state id
 
-  let st_mem_len state =
+  let st_mem_len (state : state) : int =
     match state with (_, _, mem_len, _) -> mem_len
 
-  let st_add_arg state state_before id arg_tag arg =
+  let st_add_arg (state : state) (state_before : state)
+      (id : data) (arg_tag : tag) (arg : arg) : state =
     match (arg_tag, arg) with
       | (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
                         env_add state id (st_mem_len state - 1)
 
-  let st_spoil_assignments state =
+  let st_spoil_assignments (state : state) : state =
     match state with (env, mem, mem_len, assignments) ->
     (* TODO: use env var ids instead of mem_ids ?? *)
     (env, List.fold_left (fun mem id -> list_replace mem (inv_id mem_len @@ env_get state id) BotV) mem assignments, mem_len, [])
 
   let list_drop n xs = List.of_seq @@ Seq.drop n @@ List.to_seq xs
 
-  let rec eval_stmt state prog stmt =
+  let rec eval_stmt (state : state) (prog : fun_decl list) (stmt : stmt) : state =
     match stmt with
       | Call (f_id, args) -> eval_fun state prog (List.nth prog f_id) (List.map (fun arg -> LValue arg) args)
       | Read id -> mem_check state id
       | Write id -> mem_set state id UnitV
 
-  and eval_body state prog body =
+  and eval_body (state : state) (prog : fun_decl list) (body : body) : state =
     List.fold_left (fun state stmt -> eval_stmt state prog stmt) state body
 
-  and eval_fun state prog decl args =
+  and eval_fun (state : state) (prog : fun_decl list) (decl : fun_decl) (args : arg list) : state =
     match decl with (arg_tags, body) ->
     match state with (env_before, mem_before, len_before, assignments_before) as state_before ->
     let state = ([], mem_before, len_before, []) in
@@ -99,14 +102,14 @@ struct
     match state with (_env, mem, len, _assignments) ->
     (env_before, list_drop (len - len_before) mem, len_before, assignments_before) (* TODO: save some assignments ?? *)
 
-  and eval_fun_empty_args state prog decl =
+  and eval_fun_empty_args (state : state) (prog : fun_decl list) (decl : fun_decl) : state =
     match decl with (arg_tags, _) ->
     let args = List.map (fun _ -> RValue) arg_tags in
     eval_fun state prog decl args
 
-  let empty_state = ([], [], 0, [])
+  let empty_state : state = ([], [], 0, [])
 
-  let eval_prog (prog, main_decl) = ignore @@ eval_fun_empty_args empty_state prog main_decl
+  let eval_prog ((prog, main_decl) : prog) = ignore @@ eval_fun_empty_args empty_state prog main_decl
 
   (* tests *)