New decode module

1 files changed, 44 insertions, 0 deletions

diff --git a/src/gleam_stdlib_decode_ffi.erl b/src/gleam_stdlib_decode_ffi.erl
new file mode 100644
index 0000000..35af05e
--- /dev/null
+++ b/src/gleam_stdlib_decode_ffi.erl
@@ -0,0 +1,44 @@
+-module(gleam_stdlib_decode_ffi).
+
+-export([strict_index/2, list/5, dict/1]).
+
+strict_index([X | _], 0) ->
+    {ok, {some, X}};
+strict_index([_, X | _], 1) ->
+    {ok, {some, X}};
+strict_index(Tuple, Index) when is_tuple(Tuple) andalso is_integer(Index) ->
+    {ok, try
+        {some, element(Index + 1, Tuple)}
+    catch _:_ -> 
+        none
+    end};
+strict_index(Map, Key) when is_map(Map) ->
+    {ok, try
+        {some, maps:get(Key, Map)}
+    catch _:_ -> 
+        none
+    end};
+strict_index(_, Index) when is_integer(Index) ->
+    {error, <<"Indexable">>};
+strict_index(_, _) ->
+    {error, <<"Dict">>}.
+
+list(T, A, B, C, D) when is_tuple(T) ->
+    list(tuple_to_list(T), A, B, C, D);
+list([], _, _, _, Acc) ->
+    {lists:reverse(Acc), []};
+list([X | Xs], Decode, PushPath, Index, Acc) ->
+    {Out, Errors} = Decode(X),
+    case Errors of
+        [] -> list(Xs, Decode, PushPath, Index + 1, [Out | Acc]);
+        _ -> PushPath({[], Errors}, integer_to_binary(Index))
+    end;
+list(Unexpected, _, _, _, []) ->
+    Found = gleam@dynamic:classify(Unexpected),
+    Error = {decode_error, <<"List"/utf8>>, Found, []},
+    {[], [Error]};
+list(_, _, _, _, Acc) ->
+    {lists:reverse(Acc), []}.
+
+dict(#{} = Data) -> {ok, Data};
+dict(_) -> {error, nil}.