optic

%%%-------------------------------------------------------------------

%%% @doc

%%% Utility functions for constructing optics from lists of selectors.

%%% @end

%%%-------------------------------------------------------------------

-module(optic_path).

-type path() :: string() | binary() | non_neg_integer() | '*'.
%% A single path component.

-type paths() :: [path()].
%% A list of path components.


%% API

-export([new/1]).

-export_type([path/0,

              paths/0]).

%%%===================================================================

%%% API

%%%===================================================================


%% @doc

%% Construct a list of optics from a path. The type of the path

%% component determines the optic used:

%%

%% <ul>

%% <li>string: A key for a map-like structure.</li>

%% <li>binary: A key for a map-like structure.</li>

%% <li>integer: An index into a list-like structure.</li>

%% <li>'*': All elements of a list.</li>

%% </ul>

%%

%% This heavily depends on the `optic_generic' module, see the optics

%% there for the full list of containers supported.

%%

%% Example:

%%

%% ```

%% > optic:get(optic_path(["first"]), ${"first" => 1, "second" => 2}).

%% {ok,[1]}

%% '''

%% @end

%% @param Paths A list of path components to convert.

%% @returns A list of opaque optic records.

-spec new(Paths :: paths()) -> optic:optics().
new([]) ->
    [];
new([Path | Paths]) when is_list(Path); is_binary(Path) ->
    [optic_generic:key(Path) | new(Paths)];
new([Path | Paths]) when is_integer(Path), Path > 0 ->
    [optic_generic:index(Path) | new(Paths)];
new(['*' | Paths]) ->
    [optic_lists:all() | new(Paths)].