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|
open Core
open Ppxlib
let all_localities = [ `global; `local ]
let loc = Location.none
let print_expr expr = Pprintast.string_of_expression expr |> print_string
let expand extension kind ~modul expr =
List.iteri all_localities ~f:(fun i locality ->
if i > 0 then printf "----\n";
printf !"locality = %{sexp:[`local|`global]}:\n" locality;
Ppx_let_expander.expand extension kind ~modul ~locality expr |> print_expr;
printf "\n")
;;
let%expect_test "while%bind expansion" =
expand
Ppx_let_expander.bind
Ppx_let_expander.Extension_kind.default
~modul:None
[%expr
while MY_CONDITION do
MY_BODY
done];
[%expect
{|
locality = global:
let rec __let_syntax_loop__001_ () =
Let_syntax.bind MY_CONDITION
~f:(function
| true -> Let_syntax.bind MY_BODY ~f:__let_syntax_loop__001_
| false -> Let_syntax.return ())[@@ppxlib.do_not_enter_value ] in
__let_syntax_loop__001_ ()
----
locality = local:
let rec __let_syntax_loop__002_ () =
local_ let __nontail__005_ =
Let_syntax.bind MY_CONDITION
~f:(fun __let_syntax__003_ ->
local_ let __nontail__004_ =
match __let_syntax__003_ with
| true ->
Let_syntax.bind MY_BODY
~f:__let_syntax_loop__002_
| false -> Let_syntax.return () in
__nontail__004_) in
__nontail__005_[@@ppxlib.do_not_enter_value ] in
__let_syntax_loop__002_ ()
|}]
;;
let%expect_test "while%bind trivial test" =
let i = ref 0 in
while%bind.Monad.Ident
incr i;
!i <= 5
do
printf "%d\n" !i
done;
[%expect {|
1
2
3
4
5
|}]
;;
let%expect_test "monadic use" =
let open Or_error.Let_syntax in
let next i = if i < 5 then Ok (i + 1) else error_s [%message "too big"] in
let t n =
let i = ref 0 in
let result =
while%bind
let%map i' = next !i in
i := i';
!i <= n
do
printf "%d\n" !i;
Ok ()
done
in
print_s [%sexp (result : unit Or_error.t)]
in
t 3;
[%expect {|
1
2
3
(Ok ())
|}];
t 10;
[%expect {|
1
2
3
4
5
(Error "too big")
|}]
;;
|
