OCaml Zarr jsont codecs for v2/v3 and common conventions
refactor: remove dtype_jsont_fwd mutable ref
Use let rec with a lazy value and Jsont.rec' instead of a mutable
forward reference. The lazy block binds self = Jsont.rec' dtype_jsont_lazy
and uses it directly for recursive decode/encode of nested structured
dtypes.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
+17
-22
+17
-22
src/zarr_jsont.ml
+17
-22
src/zarr_jsont.ml
···
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| `Raw n -> Printf.sprintf "|V%d" n
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| `Structured _ -> invalid_arg "dtype: encode_typestr called on structured dtype"
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-
(* Forward reference to allow recursive dtype_jsont. *)
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let dtype_jsont_fwd : dtype Jsont.t ref = ref (Jsont.todo ~kind:"dtype" ())
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-
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-
let dtype_jsont : dtype Jsont.t = Jsont.rec' (lazy (
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+
let rec dtype_jsont_lazy : dtype Jsont.t Lazy.t = lazy (
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+
let self = Jsont.rec' dtype_jsont_lazy in
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let simple_codec =
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Jsont.map ~kind:"dtype_string"
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~dec:parse_typestr
···
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| j -> invalid_arg (Format.asprintf "dtype: expected int in shape, got %a" Jsont.pp_json j))
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items
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in
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-
(* Decode a single field descriptor from a JSON list:
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-
["name", "<f4"] or ["name", "<f4", [3, 2]] *)
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+
let decode_nested json =
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+
match Jsont.Json.decode self json with
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+
| Ok v -> v
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+
| Error e -> invalid_arg (Printf.sprintf "dtype: nested structured decode error: %s" e)
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+
in
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+
let encode_nested dt =
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+
match Jsont.Json.encode self dt with
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+
| Ok j -> j
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+
| Error e -> invalid_arg (Printf.sprintf "dtype: encode error: %s" e)
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+
in
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let decode_field (json_items : Jsont.json list) : string * dtype * int list option =
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match json_items with
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| [ Jsont.String (name, _); Jsont.String (typestr, _) ] ->
···
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| [ Jsont.String (name, _); Jsont.String (typestr, _); Jsont.Array (shape_items, _) ] ->
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(name, parse_typestr typestr, Some (decode_shape shape_items))
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| [ Jsont.String (name, _); (Jsont.Array _ as nested_json) ] ->
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-
let nested = match Jsont.Json.decode !dtype_jsont_fwd nested_json with
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-
| Ok v -> v
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-
| Error e -> invalid_arg (Printf.sprintf "dtype: nested structured decode error: %s" e)
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-
in
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-
(name, nested, None)
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+
(name, decode_nested nested_json, None)
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| [ Jsont.String (name, _); (Jsont.Array _ as nested_json); Jsont.Array (shape_items, _) ] ->
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-
let nested = match Jsont.Json.decode !dtype_jsont_fwd nested_json with
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-
| Ok v -> v
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-
| Error e -> invalid_arg (Printf.sprintf "dtype: nested structured decode error: %s" e)
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-
in
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(name, nested, Some (decode_shape shape_items))
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+
(name, decode_nested nested_json, Some (decode_shape shape_items))
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| _ -> invalid_arg "dtype: invalid field descriptor"
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in
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let structured_codec =
···
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| `Structured fields ->
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List.map (fun (name, dt, shape_opt) ->
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let name_json = Jsont.Json.string name in
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-
let dtype_json = match Jsont.Json.encode !dtype_jsont_fwd dt with
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-
| Ok j -> j
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-
| Error e -> invalid_arg (Printf.sprintf "dtype: encode error: %s" e)
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-
in
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+
let dtype_json = encode_nested dt in
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match shape_opt with
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| None -> Jsont.Json.list [ name_json; dtype_json ]
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| Some shape ->
···
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| `Structured _ -> structured_codec
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| _ -> simple_codec)
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()
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-
))
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+
)
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-
let () = dtype_jsont_fwd := dtype_jsont
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+
let dtype_jsont : dtype Jsont.t = Jsont.rec' dtype_jsont_lazy
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module Other_ext = struct
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type t = { name : string; configuration : Jsont.json option; must_understand : bool }