1 files changed, 388 insertions, 0 deletions

diff --git a/lib/kDL_lens_result.ml b/lib/kDL_lens_result.ml
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+(*─────────────────────────────────────────────────────────────────────────────┐
+│ SPDX-FileCopyrightText: eilveli                                              │
+│ SPDX-FileContributor: toastal <toastal@posteo.net                            │
+│ SPDX-License-Identifier: MPL-2.0                                             │
+│                                                                              │
+│ Upstream: https://github.com/eilvelia/ocaml-kdl                              │
+│ Purpose: address “note: we can possibly replace option with result for more  │
+│ detailed errors”                                                             │
+│                                                                              │
+│ Short-comings: no ‘trail’ for the errors & not extensible with user-defined  │
+│ errors with ('a, 'b, 'err) proving difficult to work with                    │
+└─────────────────────────────────────────────────────────────────────────────*)
+
+type lerr = [
+	| `Cannot_each
+	| `Cannot_replace
+	| `Missing_annot
+	| `Missing_index of int
+	| `Missing_prop of string
+	| `Missing_top
+	| `Not_found of string * string option
+	| `Mismatched_type
+	| `Wrong_type_bool
+	| `Wrong_type_float
+	| `Wrong_type_Int
+	| `Wrong_type_Int32
+	| `Wrong_type_Int64
+	| `Wrong_type_native_int
+	| `Wrong_type_null
+	| `Wrong_type_number
+	| `Wrong_type_string
+	| `Wrong_type_stringNumber
+]
+[@@deriving show]
+
+let pp_lerr fmt = function
+	| `Cannot_each -> Fmt.pf fmt "Cannot each"
+	| `Cannot_replace -> Fmt.pf fmt "Cannot replace"
+	| `Missing_annot -> Fmt.pf fmt "Missing annotation"
+	| `Missing_prop prop -> Fmt.pf fmt "Missing property “%s”" prop
+	| `Missing_index idx -> Fmt.pf fmt "Missing index “%d”" idx
+	| `Missing_top -> Fmt.pf fmt "Missing top-level node"
+	| `Not_found (name, annot) ->
+		begin
+			match annot with
+			| None -> Fmt.pf fmt "Not found “%s”" name
+			| Some a -> Fmt.pf fmt "Not found “%s” with annotation (%s)" name a
+		end
+	| `Mismatched_type -> Fmt.pf fmt "Mismatched type"
+	| `Wrong_type_bool -> Fmt.pf fmt "Wrong type, expected a boolean"
+	| `Wrong_type_float -> Fmt.pf fmt "Wrong type, expected a float"
+	| `Wrong_type_Int -> Fmt.pf fmt "Wrong type, expected an int"
+	| `Wrong_type_Int32 -> Fmt.pf fmt "Wrong type, expected an int32"
+	| `Wrong_type_Int64 -> Fmt.pf fmt "Wrong type, expected an int64"
+	| `Wrong_type_native_int -> Fmt.pf fmt "Wrong type, expected a native int"
+	| `Wrong_type_null -> Fmt.pf fmt "Wrong type, expected a null"
+	| `Wrong_type_number -> Fmt.pf fmt "Wrong type, expected a number"
+	| `Wrong_type_string -> Fmt.pf fmt "Wrong type, expected a string"
+	| `Wrong_type_stringNumber -> Fmt.pf fmt "Wrong type, expected a string number"
+
+open Kdl
+
+(* note: we can possibly replace option with result for more detailed errors *)
+
+type ('s, 'a) lens = {
+	get: 's -> ('a, lerr) result;
+	set: 'a -> 's -> ('s, lerr) result;
+}
+
+let get a lens = lens.get a
+
+let set a v lens = lens.set v a
+
+let get_exn a lens =
+	match lens.get a with
+	| Ok v -> v
+	(*| Error e -> failwith (String.concat "; " (List.map lerr_to_string e))*)
+	| Error e -> failwith (show_lerr e)
+
+let set_exn a v lens =
+	match lens.set v a with
+	| Ok v -> v
+	(*| Error e -> failwith (String.concat "; " (List.map lerr_to_string e))*)
+	| Error e -> failwith (show_lerr e)
+
+(* note: update can possibly be added to the definition of [lens] to increase
+   performance with more specialized implementations *)
+
+let update f a lens =
+	match lens.get a with
+	| Error e -> Error e
+	| Ok value ->
+		match f value with
+		| Ok value' -> lens.set value' a
+		| Error e -> Error e
+
+let compose l1 l2 = {
+	get = (fun x ->
+		match l2.get x with
+		| Ok x' -> l1.get x'
+		| Error e -> Error e
+	);
+	set = (fun v a -> update (l1.set v) a l2)
+}
+
+let ( // ) l1 l2 = compose l2 l1
+
+let (|--) = ( // )
+
+let (.@()) = get
+let (.@() <-) a l v = set a v l
+
+let (.@!()) = get_exn
+let (.@!() <-) a l v = set_exn a v l
+
+let node_name = {
+	get = (fun node -> Ok node.name);
+	set = (fun name node -> Ok {node with name});
+}
+
+let node_annot = {
+	get = (fun node -> Option.to_result ~none: `Missing_annot node.annot);
+	set = (fun annot node -> Ok {node with annot = Some annot});
+}
+
+(* Unset the annotation by passing None *)
+let node_annot_opt = {
+	get = (fun node -> Ok node.annot);
+	set = (fun annot node -> Ok {node with annot});
+}
+
+let args = {
+	get = (fun node -> Ok node.args);
+	set = (fun args node -> Ok {node with args});
+}
+
+let props = {
+	get = (fun node -> Ok node.props);
+	set = (fun props node -> Ok {node with props});
+}
+
+let children = {
+	get = (fun node -> Ok node.children);
+	set = (fun children node -> Ok {node with children});
+}
+
+let top = {
+	get = (function node :: _ -> Ok node | [] -> Error `Missing_top);
+	set = (fun node -> function _ :: xs -> Ok (node :: xs) | [] -> Error `Missing_top);
+}
+
+open struct
+	let nth_and_replace n x' list =
+		let found = ref false in
+		(* Note: Unlike List.mapi, this stops iterating when we've found the element *)
+		let [@tail_mod_cons] rec go i = function
+			| [] -> []
+			| _ :: xs when i = n -> found := true; x' :: xs
+			| x :: xs -> x :: go (i + 1) xs
+		in
+		let result = go 0 list in
+		if !found then Ok result else Error (`Missing_index n)
+
+	let filter_and_replace f replace_list list =
+		let found = ref false in
+		let f (replace, result) x =
+			if f x then
+				begin
+					found := true;
+					match replace with
+					| x' :: xs -> xs, x' :: result
+					| [] -> [], x :: result
+				end
+			else
+				replace, x :: result
+		in
+		let _, list = List.fold_left f (replace_list, []) list in
+		if !found then Ok (List.rev list) else Error `Cannot_replace
+
+	let [@inline]matches_node ?annot name node =
+		String.equal node.name name
+		&& (
+			match annot with
+			| Some a ->
+				(
+					match node.annot with
+					| Some a' -> String.equal a a'
+					| None -> false
+				)
+			| None -> true
+		)
+
+	let rec find_node n annot name = function
+		| [] -> Error (`Not_found (name, annot))
+		| x :: xs when matches_node ?annot name x ->
+			if n <= 0 then Ok x else find_node (n - 1) annot name xs
+		| _ :: xs -> find_node n annot name xs
+
+	let find_and_replace_node nth annot name x' list =
+		let found = ref false in
+		let [@tail_mod_cons] rec go n = function
+			| [] -> []
+			| x :: xs when matches_node ?annot name x ->
+				if n <= 0 then (found := true; x' :: xs) else x :: go (n - 1) xs
+			| x :: xs -> x :: go n xs
+		in
+		let result = go nth list in
+		if !found then Ok result else Error (`Not_found (name, annot))
+end
+
+let nth n = {
+	get = (fun list ->
+		List.nth_opt list n
+		|> Option.to_result ~none: (`Missing_index n)
+	);
+	set = (fun x' list -> nth_and_replace n x' list)
+}
+
+(* these operations are O(n), and update is quite inefficient *)
+let arg n = {
+	(* Inlined [nth] instead of [args // nth n] *)
+	get = (fun node ->
+		List.nth_opt node.args n
+		|> Option.to_result ~none: (`Missing_index n)
+	);
+	set = (fun arg' node ->
+		nth_and_replace n arg' node.args
+		|> Result.map (fun args -> {node with args})
+	)
+}
+
+let first_arg = arg 0
+
+let prop key = {
+	get = (fun node ->
+		List.assoc_opt key node.props
+		|> Option.to_result ~none: (`Missing_prop key)
+	);
+	set = (fun v' node ->
+		let found = ref false in
+		let f (k, v) = if k = key then (found := true; k, v') else k, v in
+		let props = List.map f node.props in
+		if !found then Ok {node with props} else Error (`Missing_prop key)
+	)
+}
+
+let node ?(nth = 0) ?annot (name : string) = {
+	get = (fun nodes -> find_node nth annot name nodes);
+	set = (fun node' nodes -> find_and_replace_node nth annot name node' nodes)
+}
+
+let node_many ?annot (name : string) =
+	let matches = matches_node ?annot name in
+	{
+		get = (fun nodes ->
+			match List.filter matches nodes with
+			| [] -> Error (`Not_found (name, annot))
+			| xs -> Ok xs
+		);
+		set = (fun nodes' nodes -> filter_and_replace matches nodes' nodes)
+	}
+
+let node_nth : int -> (node list, node) lens = nth
+
+(* TODO: get node by annot only? *)
+
+let child ?nth ?annot name = children // node ?nth ?annot name
+let child_many ?annot name = children // node_many ?annot name
+let child_nth n = children // node_nth n
+
+let value : (annot_value, value) lens = {
+	get = (fun (_, v) -> Ok v);
+	set = (fun v' (a, _) -> Ok (a, v'));
+}
+
+let annot : (annot_value, string) lens = {
+	get = (fun (a, _) -> Option.to_result ~none: `Missing_annot a);
+	set = (fun a' (_, v) -> Ok (Some a', v));
+}
+
+let annot_opt : (annot_value, string option) lens = {
+	get = (fun (a, _) -> Ok a);
+	set = (fun a' (_, v) -> Ok (a', v));
+}
+
+let string = {
+	get = (function `String str -> Ok str | _ -> Error `Wrong_type_string);
+	set = (fun value' _value -> Ok (`String value'));
+}
+
+(* Ast.Num.of_string not exposed *)
+let number : (value, number) lens = {
+	get = (fun n -> L.number.get n |> Option.to_result ~none: `Wrong_type_number);
+	set = (fun num n -> L.number.set num n |> Option.to_result ~none: `Wrong_type_number);
+}
+
+let string_number : (value, string) lens = {
+	get = (fun n -> L.string_number.get n |> Option.to_result ~none: `Wrong_type_stringNumber);
+	set = (fun x n -> L.string_number.set x n |> Option.to_result ~none: `Wrong_type_stringNumber);
+}
+
+let float_number : (value, float) lens = {
+	get = (fun n -> L.float_number.get n |> Option.to_result ~none: `Wrong_type_float);
+	set = (fun x n -> L.float_number.set x n |> Option.to_result ~none: `Wrong_type_float);
+}
+
+let int_number : (value, int) lens = {
+	get = (fun n -> L.int_number.get n |> Option.to_result ~none: `Wrong_type_Int);
+	set = (fun x n -> L.int_number.set x n |> Option.to_result ~none: `Wrong_type_Int);
+}
+
+let int32_number : (value, int32) lens = {
+	get = (fun n -> L.int32_number.get n |> Option.to_result ~none: `Wrong_type_Int32);
+	set = (fun x n -> L.int32_number.set x n |> Option.to_result ~none: `Wrong_type_Int32);
+}
+
+let int64_number : (value, int64) lens = {
+	get = (fun n -> L.int64_number.get n |> Option.to_result ~none: `Wrong_type_Int64);
+	set = (fun x n -> L.int64_number.set x n |> Option.to_result ~none: `Wrong_type_Int64);
+}
+
+let nativeint_number : (value, nativeint) lens = {
+	get = (fun n -> L.nativeint_number.get n |> Option.to_result ~none: `Wrong_type_native_int);
+	set = (fun x n -> L.nativeint_number.set x n |> Option.to_result ~none: `Wrong_type_native_int);
+}
+
+let bool = {
+	get = (function `Bool b -> Ok b | _ -> Error `Wrong_type_bool);
+	set = (fun value' _value -> Ok (`Bool value'))
+}
+
+let null = {
+	get = (function `Null -> Ok () | _ -> Error `Wrong_type_null);
+	set = (fun _ _ -> Ok `Null)
+}
+
+let string_value : (annot_value, string) lens = value // string
+let number_value : (annot_value, number) lens = value // number
+let string_number_value : (annot_value, string) lens = value // string_number
+let float_number_value : (annot_value, float) lens = value // float_number
+let int_number_value : (annot_value, int) lens = value // int_number
+let int32_number_value : (annot_value, int32) lens = value // int32_number
+let int64_number_value : (annot_value, int64) lens = value // int64_number
+let nativeint_number_value : (annot_value, nativeint) lens =
+	value // nativeint_number
+let bool_value : (annot_value, bool) lens = value // bool
+let null_value : (annot_value, unit) lens = value // null
+
+let filter f = {
+	get = (fun list -> Ok (List.filter f list));
+	set = (fun replace list -> filter_and_replace f replace list)
+}
+
+open struct
+	exception Short_circuit
+
+	let mapm_option f list =
+		let g a =
+			match f a with
+			| Ok x -> x
+			| Error _ -> raise_notrace Short_circuit
+		in
+		try
+			Ok (List.map g list)
+		with
+			| Short_circuit -> Error `Cannot_each
+end
+
+let each l = {
+	get = (fun list -> mapm_option l.get list);
+	set = (fun replace_list list ->
+		let f (replace, result) v =
+			match replace with
+			| v' :: replace_rest ->
+				(
+					match l.set v' v with
+					| Ok x -> replace_rest, x :: result
+					| Error _ -> raise_notrace Short_circuit
+				)
+			| [] -> [], v :: result
+		in
+		try
+			let _, list = List.fold_left f (replace_list, []) list in
+			Ok (List.rev list)
+		with
+			| Short_circuit -> Error `Cannot_each
+	)
+}