let (Int i1, s') = eval t1 g s
in let (Int i2, s'') = eval t2 g s'
in (Int (i1 + i2), s'')
- | Variable (var) -> (
+ | Variable (var) -> ((
(* we don't handle cases where g doesn't bind var to any value *)
match List.assoc var g with
| Nonrecursive value -> value
(* we update savedg to bind self_var to rec_closure here *)
let savedg' = (self_var, rec_closure) :: savedg
in Closure (arg_var, body, savedg')
- ), s
+ ), s)
| Let (var_to_bind, t2, t3) ->
(* evaluate t3 under a new assignment where var_to_bind has been bound to
the result of evaluating t2 under the current assignment *)
in let g' = (var_to_bind, Recursive_Closure (var_to_bind, arg_var, body, savedg)) :: g
in eval t3 g' s'
| Newref (t1) ->
- let (starting_val, s') = eval t1 g s
+ let (value1, s') = eval t1 g s
(* note that s' may be different from s, if t1 itself contained any mutation operations *)
(* now we want to retrieve the next free index in s' *)
in let new_index = List.length s'
- (* now we want to insert starting_val there; the following is an easy but inefficient way to do it *)
- in let s'' = List.append s' [starting_val]
+ (* now we want to insert value1 there; the following is an easy but inefficient way to do it *)
+ in let s'' = List.append s' [value1]
(* now we return a pair of a wrapped new_index, and the new store *)
in (Mutcell new_index, s'')
| Deref (t1) ->
(* we don't handle cases where t1 doesn't evaluate to a Mutcell *)
let (Mutcell index1, s') = eval t1 g s
(* note that s' may be different from s, if t1 itself contained any mutation operations *)
- in let (new_value, s'') = eval t2 g s'
- (* now we create a list which is just like s'' except it has new_value in index1 *)
+ in let (value2, s'') = eval t2 g s'
+ (* now we create a list which is just like s'' except it has value2 in index1 *)
in let rec replace_nth lst m =
match lst with
| [] -> failwith "list too short"
- | x::xs when m = 0 -> new_value :: xs
+ | x::xs when m = 0 -> value2 :: xs
| x::xs -> x :: replace_nth xs (m - 1)
in let s''' = replace_nth s'' index1
(* we'll arbitrarily return Int 42 as the expressed_value of a Setref operation *)