dream: chat (ws rooms) + todo (forms+CSRF) demos + 17 tests

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

lib/dream/demos/chat.sx

@@ -0,0 +1,46 @@
+;; lib/dream/demos/chat.sx — multi-room WebSocket chat (chat.ml).
+;; A room registry holds the live connections per room; each ws session joins its
+;; room, broadcasts every received message to the room, and leaves on close.
+
+(define dream-chat-rooms (fn () (let ((rooms {})) {:join (fn (room ws) (set! rooms (assoc rooms room (concat (or (get rooms room) (list)) (list ws))))) :broadcast (fn (room msg) (for-each (fn (w) (dream-send w msg)) (or (get rooms room) (list)))) :members (fn (room) (or (get rooms room) (list))) :leave (fn (room ws) (set! rooms (assoc rooms room (filter (fn (w) (not (= w ws))) (or (get rooms room) (list))))))})))
+
+(define
+  dream-chat-loop
+  (fn
+    (rooms room ws)
+    (let
+      ((m (dream-receive ws)))
+      (if
+        (nil? m)
+        (begin ((get rooms :leave) room ws) (dream-close ws))
+        (begin
+          ((get rooms :broadcast) room m)
+          (dream-chat-loop rooms room ws))))))
+
+(define
+  dream-chat-session
+  (fn
+    (rooms room)
+    (fn
+      (ws)
+      (begin ((get rooms :join) room ws) (dream-chat-loop rooms room ws)))))
+
+(define
+  dream-chat-route
+  (fn
+    (rooms)
+    (fn
+      (req)
+      ((dream-websocket (dream-chat-session rooms (dream-param req "room")))
+        req))))
+
+(define
+  dream-chat-app-with
+  (fn
+    (rooms)
+    (dream-router
+      (list
+        (dream-get "/" (fn (req) (dream-html "<h1>Rooms</h1>")))
+        (dream-get "/chat/:room" (dream-chat-route rooms))))))
+
+;; entry point: (dream-run (dream-chat-app-with (dream-chat-rooms)))