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72eaefac135502233e5c7c70265a8472dda37078
rose-ash/shared/sx/ref/signals.sx
giles 455e48df07 Replace invoke with cek-call in reactive island primitives 
All signal operations (computed, effect, batch, etc.) now dispatch
function calls through cek-call, which routes SX lambdas via cek-run
and native callables via apply. This replaces the invoke shim.

Key changes:
- cek.sx: add cek-call (defined before reactive-shift-deref), replace
  invoke in subscriber disposal and ReactiveResetFrame handler
- signals.sx: replace all 11 invoke calls with cek-call
- js.sx: fix octal escape in js-quote-string (char-from-code 0)
- platform_js.py: fix JS append to match Python (list concat semantics),
  add Continuation type guard in PLATFORM_CEK_JS, add scheduleIdle
  safety check, module ordering (cek before signals)
- platform_py.py: fix ident-char regex (remove [ ] from valid chars),
  module ordering (cek before signals)
- run_js_sx.py: emit PLATFORM_CEK_JS before transpiled spec files
- page-functions.sx: add cek and provide page functions for SX URLs

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
2026-03-14 10:11:48 +00:00

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;; ==========================================================================
;; signals.sx — Reactive signal runtime specification
;;
;; Defines the signal primitive: a container for a value that notifies
;; subscribers when it changes. Signals are the reactive state primitive
;; for SX islands.
;;
;; Signals are pure computation — no DOM, no IO. The reactive rendering
;; layer (adapter-dom.sx) subscribes DOM nodes to signals. The server
;; adapter (adapter-html.sx) reads signal values without subscribing.
;;
;; Signals are plain dicts with a "__signal" marker key. No platform
;; primitives needed — all signal operations are pure SX.
;;
;; Reactive tracking and island lifecycle use the general scoped effects
;; system (scope-push!/scope-pop!/context) instead of separate globals.
;; Two scope names:
;; "sx-reactive" — tracking context for computed/effect dep discovery
;; "sx-island-scope" — island disposable collector
;;
;; Scope-based tracking:
;; (scope-push! "sx-reactive" {:deps (list) :notify fn}) → void
;; (scope-pop! "sx-reactive") → void
;; (context "sx-reactive" nil) → dict or nil
;;
;; CEK callable dispatch:
;; (cek-call f args) → any — call f with args list via CEK.
;; Dispatches through cek-run for SX
;; lambdas, apply for native callables.
;; Defined in cek.sx.
;;
;; ==========================================================================
;; --------------------------------------------------------------------------
;; Signal container — plain dict with marker key
;; --------------------------------------------------------------------------
;;
;; A signal is a dict: {"__signal" true, "value" v, "subscribers" [], "deps" []}
;; type-of returns "dict". Use signal? to distinguish from regular dicts.
(define make-signal (fn (value)
(dict "__signal" true "value" value "subscribers" (list) "deps" (list))))
(define signal? (fn (x)
(and (dict? x) (has-key? x "__signal"))))
(define signal-value (fn (s) (get s "value")))
(define signal-set-value! (fn (s v) (dict-set! s "value" v)))
(define signal-subscribers (fn (s) (get s "subscribers")))
(define signal-add-sub! (fn (s f)
(when (not (contains? (get s "subscribers") f))
(append! (get s "subscribers") f))))
(define signal-remove-sub! (fn (s f)
(dict-set! s "subscribers"
(filter (fn (sub) (not (identical? sub f)))
(get s "subscribers")))))
(define signal-deps (fn (s) (get s "deps")))
(define signal-set-deps! (fn (s deps) (dict-set! s "deps" deps)))
;; --------------------------------------------------------------------------
;; 1. signal — create a reactive container
;; --------------------------------------------------------------------------
(define signal :effects []
(fn ((initial-value :as any))
(make-signal initial-value)))
;; --------------------------------------------------------------------------
;; 2. deref — read signal value, subscribe current reactive context
;; --------------------------------------------------------------------------
;;
;; In a reactive context (inside effect or computed), deref registers the
;; signal as a dependency. Outside reactive context, deref just returns
;; the current value — no subscription, no overhead.
(define deref :effects []
(fn ((s :as any))
(if (not (signal? s))
s ;; non-signal values pass through
(let ((ctx (context "sx-reactive" nil)))
(when ctx
;; Register this signal as a dependency of the current context
(let ((dep-list (get ctx "deps"))
(notify-fn (get ctx "notify")))
(when (not (contains? dep-list s))
(append! dep-list s)
(signal-add-sub! s notify-fn))))
(signal-value s)))))
;; --------------------------------------------------------------------------
;; 3. reset! — write a new value, notify subscribers
;; --------------------------------------------------------------------------
(define reset! :effects [mutation]
(fn ((s :as signal) value)
(when (signal? s)
(let ((old (signal-value s)))
(when (not (identical? old value))
(signal-set-value! s value)
(notify-subscribers s))))))
;; --------------------------------------------------------------------------
;; 4. swap! — update signal via function
;; --------------------------------------------------------------------------
(define swap! :effects [mutation]
(fn ((s :as signal) (f :as lambda) &rest args)
(when (signal? s)
(let ((old (signal-value s))
(new-val (apply f (cons old args))))
(when (not (identical? old new-val))
(signal-set-value! s new-val)
(notify-subscribers s))))))
;; --------------------------------------------------------------------------
;; 5. computed — derived signal with automatic dependency tracking
;; --------------------------------------------------------------------------
;;
;; A computed signal wraps a zero-arg function. It re-evaluates when any
;; of its dependencies change. The dependency set is discovered automatically
;; by tracking deref calls during evaluation.
(define computed :effects [mutation]
(fn ((compute-fn :as lambda))
(let ((s (make-signal nil))
(deps (list))
(compute-ctx nil))
;; The notify function — called when a dependency changes
(let ((recompute
(fn ()
;; Unsubscribe from old deps
(for-each
(fn ((dep :as signal)) (signal-remove-sub! dep recompute))
(signal-deps s))
(signal-set-deps! s (list))
;; Push scope-based tracking context for this computed
(let ((ctx (dict "deps" (list) "notify" recompute)))
(scope-push! "sx-reactive" ctx)
(let ((new-val (cek-call compute-fn nil)))
(scope-pop! "sx-reactive")
;; Save discovered deps
(signal-set-deps! s (get ctx "deps"))
;; Update value + notify downstream
(let ((old (signal-value s)))
(signal-set-value! s new-val)
(when (not (identical? old new-val))
(notify-subscribers s))))))))
;; Initial computation
(recompute)
;; Auto-register disposal with island scope
(register-in-scope (fn () (dispose-computed s)))
s))))
;; --------------------------------------------------------------------------
;; 6. effect — side effect that runs when dependencies change
;; --------------------------------------------------------------------------
;;
;; Like computed, but doesn't produce a signal value. Returns a dispose
;; function that tears down the effect.
(define effect :effects [mutation]
(fn ((effect-fn :as lambda))
(let ((deps (list))
(disposed false)
(cleanup-fn nil))
(let ((run-effect
(fn ()
(when (not disposed)
;; Run previous cleanup if any
(when cleanup-fn (cek-call cleanup-fn nil))
;; Unsubscribe from old deps
(for-each
(fn ((dep :as signal)) (signal-remove-sub! dep run-effect))
deps)
(set! deps (list))
;; Push scope-based tracking context
(let ((ctx (dict "deps" (list) "notify" run-effect)))
(scope-push! "sx-reactive" ctx)
(let ((result (cek-call effect-fn nil)))
(scope-pop! "sx-reactive")
(set! deps (get ctx "deps"))
;; If effect returns a function, it's the cleanup
(when (callable? result)
(set! cleanup-fn result))))))))
;; Initial run
(run-effect)
;; Return dispose function
(let ((dispose-fn
(fn ()
(set! disposed true)
(when cleanup-fn (cek-call cleanup-fn nil))
(for-each
(fn ((dep :as signal)) (signal-remove-sub! dep run-effect))
deps)
(set! deps (list)))))
;; Auto-register with island scope so disposal happens on swap
(register-in-scope dispose-fn)
dispose-fn)))))
;; --------------------------------------------------------------------------
;; 7. batch — group multiple signal writes into one notification pass
;; --------------------------------------------------------------------------
;;
;; During a batch, signal writes are deferred. Subscribers are notified
;; once at the end, after all values have been updated.
(define *batch-depth* 0)
(define *batch-queue* (list))
(define batch :effects [mutation]
(fn ((thunk :as lambda))
(set! *batch-depth* (+ *batch-depth* 1))
(cek-call thunk nil)
(set! *batch-depth* (- *batch-depth* 1))
(when (= *batch-depth* 0)
(let ((queue *batch-queue*))
(set! *batch-queue* (list))
;; Collect unique subscribers across all queued signals,
;; then notify each exactly once.
(let ((seen (list))
(pending (list)))
(for-each
(fn ((s :as signal))
(for-each
(fn ((sub :as lambda))
(when (not (contains? seen sub))
(append! seen sub)
(append! pending sub)))
(signal-subscribers s)))
queue)
(for-each (fn ((sub :as lambda)) (sub)) pending))))))
;; --------------------------------------------------------------------------
;; 8. notify-subscribers — internal notification dispatch
;; --------------------------------------------------------------------------
;;
;; If inside a batch, queues the signal. Otherwise, notifies immediately.
(define notify-subscribers :effects [mutation]
(fn ((s :as signal))
(if (> *batch-depth* 0)
(when (not (contains? *batch-queue* s))
(append! *batch-queue* s))
(flush-subscribers s))))
(define flush-subscribers :effects [mutation]
(fn ((s :as signal))
(for-each
(fn ((sub :as lambda)) (sub))
(signal-subscribers s))))
;; --------------------------------------------------------------------------
;; 9. Reactive tracking context
;; --------------------------------------------------------------------------
;;
;; Tracking is now scope-based. computed/effect push a dict
;; {:deps (list) :notify fn} onto the "sx-reactive" scope stack via
;; scope-push!/scope-pop!. deref reads it via (context "sx-reactive" nil).
;; No platform primitives needed — uses the existing scope infrastructure.
;; --------------------------------------------------------------------------
;; 10. dispose — tear down a computed signal
;; --------------------------------------------------------------------------
;;
;; For computed signals, unsubscribe from all dependencies.
;; For effects, the dispose function is returned by effect itself.
(define dispose-computed :effects [mutation]
(fn ((s :as signal))
(when (signal? s)
(for-each
(fn ((dep :as signal)) (signal-remove-sub! dep nil))
(signal-deps s))
(signal-set-deps! s (list)))))
;; --------------------------------------------------------------------------
;; 11. Island scope — automatic cleanup of signals within an island
;; --------------------------------------------------------------------------
;;
;; When an island is created, all signals, effects, and computeds created
;; within it are tracked. When the island is removed from the DOM, they
;; are all disposed.
;;
;; Uses "sx-island-scope" scope name. The scope value is a collector
;; function (fn (disposable) ...) that appends to the island's disposer list.
(define with-island-scope :effects [mutation]
(fn ((scope-fn :as lambda) (body-fn :as lambda))
(scope-push! "sx-island-scope" scope-fn)
(let ((result (body-fn)))
(scope-pop! "sx-island-scope")
result)))
;; Hook into signal/effect/computed creation for scope tracking.
(define register-in-scope :effects [mutation]
(fn ((disposable :as lambda))
(let ((collector (context "sx-island-scope" nil)))
(when collector
(cek-call collector (list disposable))))))
;; ==========================================================================
;; 12. Marsh scopes — child scopes within islands
;; ==========================================================================
;;
;; Marshes are zones inside islands where server content is re-evaluated
;; in the island's reactive context. When a marsh is re-morphed with new
;; content, its old effects and computeds must be disposed WITHOUT disturbing
;; the island's own reactive graph.
;;
;; Scope hierarchy: island → marsh → effects/computeds
;; Disposing a marsh disposes its subscope. Disposing an island disposes
;; all its marshes. The signal graph is a tree, not a flat list.
;;
;; Platform interface required:
;; (dom-set-data el key val) → void — store JS value on element
;; (dom-get-data el key) → any — retrieve stored value
(define with-marsh-scope :effects [mutation io]
(fn (marsh-el (body-fn :as lambda))
;; Execute body-fn collecting all disposables into a marsh-local list.
;; Nested under the current island scope — if the island is disposed,
;; the marsh is disposed too (because island scope collected the marsh's
;; own dispose function).
(let ((disposers (list)))
(with-island-scope
(fn (d) (append! disposers d))
body-fn)
;; Store disposers on the marsh element for later cleanup
(dom-set-data marsh-el "sx-marsh-disposers" disposers))))
(define dispose-marsh-scope :effects [mutation io]
(fn (marsh-el)
;; Dispose all effects/computeds registered in this marsh's scope.
;; Parent island scope and sibling marshes are unaffected.
(let ((disposers (dom-get-data marsh-el "sx-marsh-disposers")))
(when disposers
(for-each (fn ((d :as lambda)) (cek-call d nil)) disposers)
(dom-set-data marsh-el "sx-marsh-disposers" nil)))))
;; ==========================================================================
;; 13. Named stores — page-level signal containers (L3)
;; ==========================================================================
;;
;; Stores persist across island creation/destruction. They live at page
;; scope, not island scope. When an island is swapped out and re-created,
;; it reconnects to the same store instance.
;;
;; The store registry is global page-level state. It survives island
;; disposal but is cleared on full page navigation.
(define *store-registry* (dict))
(define def-store :effects [mutation]
(fn ((name :as string) (init-fn :as lambda))
(let ((registry *store-registry*))
;; Only create the store once — subsequent calls return existing
(when (not (has-key? registry name))
(set! *store-registry* (assoc registry name (cek-call init-fn nil))))
(get *store-registry* name))))
(define use-store :effects []
(fn ((name :as string))
(if (has-key? *store-registry* name)
(get *store-registry* name)
(error (str "Store not found: " name
". Call (def-store ...) before (use-store ...).")))))
(define clear-stores :effects [mutation]
(fn ()
(set! *store-registry* (dict))))
;; ==========================================================================
;; 13. Event bridge — DOM event communication for lake→island
;; ==========================================================================
;;
;; Server-rendered content ("htmx lakes") inside reactive islands can
;; communicate with island signals via DOM custom events. The bridge
;; pattern:
;;
;; 1. Server renders a button/link with data-sx-emit="event-name"
;; 2. When clicked, the client dispatches a CustomEvent on the element
;; 3. The event bubbles up to the island container
;; 4. An island effect listens for the event and updates signals
;;
;; This keeps server content pure HTML — no signal references needed.
;; The island effect is the only reactive code.
;;
;; Platform interface required:
;; (dom-listen el event-name handler) → remove-fn
;; (dom-dispatch el event-name detail) → void
;; (event-detail e) → any
;;
;; These are platform primitives because they require browser DOM APIs.
(define emit-event :effects [io]
(fn (el (event-name :as string) detail)
(dom-dispatch el event-name detail)))
(define on-event :effects [io]
(fn (el (event-name :as string) (handler :as lambda))
(dom-listen el event-name handler)))
;; Convenience: create an effect that listens for a DOM event on an
;; element and writes the event detail (or a transformed value) into
;; a target signal. Returns the effect's dispose function.
;; When the effect is disposed (island teardown), the listener is
;; removed automatically via the cleanup return.
(define bridge-event :effects [mutation io]
(fn (el (event-name :as string) (target-signal :as signal) transform-fn)
(effect (fn ()
(let ((remove (dom-listen el event-name
(fn (e)
(let ((detail (event-detail e))
(new-val (if transform-fn
(cek-call transform-fn (list detail))
detail)))
(reset! target-signal new-val))))))
;; Return cleanup — removes listener on dispose/re-run
remove)))))
;; ==========================================================================
;; 14. Resource — async signal with loading/resolved/error states
;; ==========================================================================
;;
;; A resource wraps an async operation (fetch, computation) and exposes
;; its state as a signal. The signal transitions through:
;; {:loading true :data nil :error nil} — initial/loading
;; {:loading false :data result :error nil} — success
;; {:loading false :data nil :error err} — failure
;;
;; Usage:
;; (let ((user (resource (fn () (fetch-json "/api/user")))))
;; (cond
;; (get (deref user) "loading") (div "Loading...")
;; (get (deref user) "error") (div "Error: " (get (deref user) "error"))
;; :else (div (get (deref user) "data"))))
;;
;; Platform interface required:
;; (promise-then promise on-resolve on-reject) → void
(define resource :effects [mutation io]
(fn ((fetch-fn :as lambda))
(let ((state (signal (dict "loading" true "data" nil "error" nil))))
;; Kick off the async operation
(promise-then (cek-call fetch-fn nil)
(fn (data) (reset! state (dict "loading" false "data" data "error" nil)))
(fn (err) (reset! state (dict "loading" false "data" nil "error" err))))
state)))
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