fed-sx-m1: Step 5b — gen_server-wrapped registry + named-process API + 12 tests

next/kernel/registry.erl

@@ -1,5 +1,8 @@
 -module(registry).
+-behaviour(gen_server).
 -export([new/0, kinds/0, register/4, lookup/3, list/2]).
+-export([start_link/0, register/3, lookup/2, list/1, stop/0]).
+-export([init/1, handle_call/3, handle_cast/2, handle_info/2]).
 
 %% Pure-functional registry for the seven bootstrap kinds.
 %%
@@ -67,3 +70,51 @@ put_pair(K, V, [P | Rest]) -> [P | put_pair(K, V, Rest)].
 find_pair(_, []) -> not_found;
 find_pair(K, [{K, V} | _]) -> {ok, V};
 find_pair(K, [_ | Rest]) -> find_pair(K, Rest).
+
+%% ── Step 5b: gen_server wrapper ─────────────────────────────────
+%%
+%% The named process owns the registry state; concurrent readers
+%% and writers serialize through gen_server:call. The pure /3 and
+%% /4 functions remain available for offline projection-replay and
+%% for tests that don't need a process at all.
+%%
+%% Port notes: gen_server:start_link returns the raw Pid (not
+%% `{ok, Pid}` as in OTP). `?MODULE` macro is unsupported here, so
+%% the registered name is the literal `registry` atom in every call.
+
+start_link() ->
+    Pid = gen_server:start_link(registry, []),
+    erlang:register(registry, Pid),
+    Pid.
+
+stop() ->
+    R = gen_server:call(registry, '$gen_stop'),
+    erlang:unregister(registry),
+    R.
+
+register(Kind, Name, Entry) ->
+    gen_server:call(registry, {register, Kind, Name, Entry}).
+
+lookup(Kind, Name) ->
+    gen_server:call(registry, {lookup, Kind, Name}).
+
+list(Kind) ->
+    gen_server:call(registry, {list, Kind}).
+
+%% gen_server callbacks
+
+init(_) -> {ok, new()}.
+
+handle_call({register, Kind, Name, Entry}, _From, State) ->
+    case register(Kind, Name, Entry, State) of
+        {ok, NewState} -> {reply, ok, NewState};
+        {error, R}     -> {reply, {error, R}, State}
+    end;
+handle_call({lookup, Kind, Name}, _From, State) ->
+    {reply, lookup(Kind, Name, State), State};
+handle_call({list, Kind}, _From, State) ->
+    {reply, list(Kind, State), State}.
+
+handle_cast(_, S) -> {noreply, S}.
+
+handle_info(_, S) -> {noreply, S}.