giles
b104663481
Core reactive primitives (signal, deref, reset!, swap!, computed, effect, batch, notify-subscribers, dispose-computed, with-island-scope, register-in-scope) moved to spec/signals.sx — pure SX, zero platform dependencies. Usable by any host: web, CLI, embedded, server, harness. Web extensions (marsh scopes, stores, event bridge, resource) remain in web/signals.sx, which now depends on spec/signals.sx. Updated all load paths: - hosts/ocaml/bin/sx_server.ml — loads spec/signals.sx before web/signals.sx - hosts/ocaml/bin/run_tests.ml — loads both in order - hosts/ocaml/browser/bundle.sh + sx-platform.js — loads core-signals.sx first - shared/sx/ocaml_bridge.py — loads spec/signals.sx before web extensions 1116/1116 OCaml tests pass. Browser reactive island preview works. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
259 lines
9.2 KiB
Plaintext
259 lines
9.2 KiB
Plaintext
;; ==========================================================================
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;; spec/signals.sx — Core reactive signal specification
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;;
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;; Defines the signal primitive: a container for a value that notifies
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;; subscribers when it changes. Signals are the core reactive state
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;; primitive for SX — usable in any context (web, CLI, embedded, server).
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;;
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;; Signals are pure computation — no DOM, no IO. Platform-specific
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;; extensions (island scopes, DOM rendering, events) live in web/signals.sx.
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;;
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;; Signals are plain dicts with a "__signal" marker key. No platform
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;; primitives needed — all signal operations are pure SX.
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;;
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;; Reactive tracking uses the general scope system:
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;; "sx-reactive" — tracking context for computed/effect dep discovery
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;; "sx-island-scope" — disposable collector (named for history, works anywhere)
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;;
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;; Scope-based tracking:
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;; (scope-push! "sx-reactive" {:deps (list) :notify fn}) → void
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;; (scope-pop! "sx-reactive") → void
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;; (context "sx-reactive" nil) → dict or nil
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;;
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;; CEK callable dispatch:
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;; (cek-call f args) → any — call f with args list via CEK machine.
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;; ==========================================================================
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;; --------------------------------------------------------------------------
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;; Signal container — plain dict with marker key
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;; --------------------------------------------------------------------------
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(define make-signal (fn (value)
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(dict "__signal" true "value" value "subscribers" (list) "deps" (list))))
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(define signal? (fn (x)
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(and (dict? x) (has-key? x "__signal"))))
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(define signal-value (fn (s) (get s "value")))
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(define signal-set-value! (fn (s v) (dict-set! s "value" v)))
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(define signal-subscribers (fn (s) (get s "subscribers")))
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(define signal-add-sub! (fn (s f)
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(when (not (contains? (get s "subscribers") f))
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(append! (get s "subscribers") f))))
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(define signal-remove-sub! (fn (s f)
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(dict-set! s "subscribers"
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(filter (fn (sub) (not (identical? sub f)))
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(get s "subscribers")))))
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(define signal-deps (fn (s) (get s "deps")))
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(define signal-set-deps! (fn (s deps) (dict-set! s "deps" deps)))
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;; --------------------------------------------------------------------------
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;; signal — create a reactive container
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;; --------------------------------------------------------------------------
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(define signal :effects []
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(fn ((initial-value :as any))
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(make-signal initial-value)))
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;; --------------------------------------------------------------------------
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;; deref — read signal value, subscribe current reactive context
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;; --------------------------------------------------------------------------
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(define deref :effects []
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(fn ((s :as any))
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(if (not (signal? s))
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s
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(let ((ctx (context "sx-reactive" nil)))
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(when ctx
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(let ((dep-list (get ctx "deps"))
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(notify-fn (get ctx "notify")))
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(when (not (contains? dep-list s))
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(append! dep-list s)
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(signal-add-sub! s notify-fn))))
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(signal-value s)))))
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;; --------------------------------------------------------------------------
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;; reset! — write a new value, notify subscribers
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;; --------------------------------------------------------------------------
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(define reset! :effects [mutation]
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(fn ((s :as signal) value)
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(when (signal? s)
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(let ((old (signal-value s)))
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(when (not (identical? old value))
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(signal-set-value! s value)
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(notify-subscribers s))))))
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;; --------------------------------------------------------------------------
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;; swap! — update signal via function
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;; --------------------------------------------------------------------------
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(define swap! :effects [mutation]
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(fn ((s :as signal) (f :as lambda) &rest args)
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(when (signal? s)
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(let ((old (signal-value s))
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(new-val (apply f (cons old args))))
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(when (not (identical? old new-val))
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(signal-set-value! s new-val)
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(notify-subscribers s))))))
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;; --------------------------------------------------------------------------
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;; computed — derived signal with automatic dependency tracking
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;; --------------------------------------------------------------------------
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(define computed :effects [mutation]
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(fn ((compute-fn :as lambda))
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(let ((s (make-signal nil))
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(deps (list))
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(compute-ctx nil))
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(let ((recompute
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(fn ()
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(for-each
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(fn ((dep :as signal)) (signal-remove-sub! dep recompute))
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(signal-deps s))
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(signal-set-deps! s (list))
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(let ((ctx (dict "deps" (list) "notify" recompute)))
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(scope-push! "sx-reactive" ctx)
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(let ((new-val (cek-call compute-fn nil)))
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(scope-pop! "sx-reactive")
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(signal-set-deps! s (get ctx "deps"))
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(let ((old (signal-value s)))
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(signal-set-value! s new-val)
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(when (not (identical? old new-val))
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(notify-subscribers s))))))))
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(recompute)
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(register-in-scope (fn () (dispose-computed s)))
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s))))
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;; --------------------------------------------------------------------------
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;; effect — side effect that runs when dependencies change
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;; --------------------------------------------------------------------------
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(define effect :effects [mutation]
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(fn ((effect-fn :as lambda))
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(let ((deps (list))
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(disposed false)
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(cleanup-fn nil))
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(let ((run-effect
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(fn ()
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(when (not disposed)
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(when cleanup-fn (cek-call cleanup-fn nil))
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(for-each
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(fn ((dep :as signal)) (signal-remove-sub! dep run-effect))
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deps)
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(set! deps (list))
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(let ((ctx (dict "deps" (list) "notify" run-effect)))
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(scope-push! "sx-reactive" ctx)
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(let ((result (cek-call effect-fn nil)))
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(scope-pop! "sx-reactive")
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(set! deps (get ctx "deps"))
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(when (callable? result)
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(set! cleanup-fn result))))))))
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(run-effect)
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(let ((dispose-fn
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(fn ()
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(set! disposed true)
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(when cleanup-fn (cek-call cleanup-fn nil))
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(for-each
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(fn ((dep :as signal)) (signal-remove-sub! dep run-effect))
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deps)
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(set! deps (list)))))
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(register-in-scope dispose-fn)
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dispose-fn)))))
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;; --------------------------------------------------------------------------
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;; batch — group multiple signal writes into one notification pass
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;; --------------------------------------------------------------------------
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(define *batch-depth* 0)
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(define *batch-queue* (list))
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(define batch :effects [mutation]
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(fn ((thunk :as lambda))
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(set! *batch-depth* (+ *batch-depth* 1))
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(cek-call thunk nil)
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(set! *batch-depth* (- *batch-depth* 1))
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(when (= *batch-depth* 0)
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(let ((queue *batch-queue*))
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(set! *batch-queue* (list))
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(let ((seen (list))
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(pending (list)))
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(for-each
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(fn ((s :as signal))
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(for-each
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(fn ((sub :as lambda))
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(when (not (contains? seen sub))
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(append! seen sub)
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(append! pending sub)))
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(signal-subscribers s)))
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queue)
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(for-each (fn ((sub :as lambda)) (sub)) pending))))))
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;; --------------------------------------------------------------------------
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;; notify-subscribers — internal notification dispatch
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;; --------------------------------------------------------------------------
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(define notify-subscribers :effects [mutation]
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(fn ((s :as signal))
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(if (> *batch-depth* 0)
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(when (not (contains? *batch-queue* s))
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(append! *batch-queue* s))
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(flush-subscribers s))))
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(define flush-subscribers :effects [mutation]
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(fn ((s :as signal))
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(for-each
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(fn ((sub :as lambda)) (sub))
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(signal-subscribers s))))
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;; --------------------------------------------------------------------------
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;; dispose-computed — tear down a computed signal
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;; --------------------------------------------------------------------------
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(define dispose-computed :effects [mutation]
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(fn ((s :as signal))
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(when (signal? s)
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(for-each
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(fn ((dep :as signal)) (signal-remove-sub! dep nil))
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(signal-deps s))
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(signal-set-deps! s (list)))))
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;; --------------------------------------------------------------------------
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;; Reactive scope — automatic cleanup of signals within a scope
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;; --------------------------------------------------------------------------
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(define with-island-scope :effects [mutation]
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(fn ((scope-fn :as lambda) (body-fn :as lambda))
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(scope-push! "sx-island-scope" scope-fn)
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(let ((result (body-fn)))
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(scope-pop! "sx-island-scope")
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result)))
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(define register-in-scope :effects [mutation]
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(fn ((disposable :as lambda))
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(let ((collector (scope-peek "sx-island-scope")))
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(when collector
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(cek-call collector (list disposable))))))
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