Add suspense, resource, and transitions — Phase 2 complete

- suspense render-dom form: shows fallback while resource loads, swaps
  to body content when resource signal resolves
- resource async signal: wraps promise into signal with loading/data/error
  dict, auto-transitions on resolve/reject via promise-then
- transition: defers signal writes to requestIdleCallback, sets pending
  signal for UI feedback during expensive operations
- Added schedule-idle, promise-then platform functions
- All Phase 2 features now marked Done in status tables

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
This commit is contained in:
2026-03-08 16:40:13 +00:00
parent a496ee6ae6
commit 7efd1b401b
6 changed files with 211 additions and 23 deletions

View File

@@ -14,7 +14,7 @@
// =========================================================================
var NIL = Object.freeze({ _nil: true, toString: function() { return "nil"; } });
var SX_VERSION = "2026-03-08T16:35:00Z";
var SX_VERSION = "2026-03-08T16:36:52Z";
function isNil(x) { return x === NIL || x === null || x === undefined; }
function isSxTruthy(x) { return x !== false && !isNil(x); }
@@ -1546,7 +1546,7 @@ return result; }, args);
var renderDomUnknownComponent = function(name) { return error((String("Unknown component: ") + String(name))); };
// RENDER_DOM_FORMS
var RENDER_DOM_FORMS = ["if", "when", "cond", "case", "let", "let*", "begin", "do", "define", "defcomp", "defisland", "defmacro", "defstyle", "defhandler", "map", "map-indexed", "filter", "for-each", "portal", "error-boundary"];
var RENDER_DOM_FORMS = ["if", "when", "cond", "case", "let", "let*", "begin", "do", "define", "defcomp", "defisland", "defmacro", "defstyle", "defhandler", "map", "map-indexed", "filter", "for-each", "portal", "error-boundary", "suspense"];
// render-dom-form?
var isRenderDomForm = function(name) { return contains(RENDER_DOM_FORMS, name); };
@@ -1604,7 +1604,7 @@ return result; }, args);
return domAppend(frag, val);
})(); }, coll);
return frag;
})() : (isSxTruthy((name == "filter")) ? renderToDom(trampoline(evalExpr(expr, env)), env, ns) : (isSxTruthy((name == "portal")) ? renderDomPortal(args, env, ns) : (isSxTruthy((name == "error-boundary")) ? renderDomErrorBoundary(args, env, ns) : (isSxTruthy((name == "for-each")) ? (function() {
})() : (isSxTruthy((name == "filter")) ? renderToDom(trampoline(evalExpr(expr, env)), env, ns) : (isSxTruthy((name == "portal")) ? renderDomPortal(args, env, ns) : (isSxTruthy((name == "error-boundary")) ? renderDomErrorBoundary(args, env, ns) : (isSxTruthy((name == "suspense")) ? renderDomSuspense(args, env, ns) : (isSxTruthy((name == "for-each")) ? (function() {
var f = trampoline(evalExpr(nth(expr, 1), env));
var coll = trampoline(evalExpr(nth(expr, 2), env));
var frag = createFragment();
@@ -1613,7 +1613,7 @@ return result; }, args);
return domAppend(frag, val);
})(); } }
return frag;
})() : renderToDom(trampoline(evalExpr(expr, env)), env, ns)))))))))))))); };
})() : renderToDom(trampoline(evalExpr(expr, env)), env, ns))))))))))))))); };
// render-lambda-dom
var renderLambdaDom = function(f, args, env, ns) { return (function() {
@@ -1805,6 +1805,30 @@ return (boundaryDisposers = []); });
})();
})(); };
// render-dom-suspense
var renderDomSuspense = function(args, env, ns) { return (function() {
var fallbackExpr = first(args);
var bodyExprs = rest(args);
var container = domCreateElement("div", NIL);
domSetAttr(container, "data-sx-suspense", "true");
domAppend(container, renderToDom(fallbackExpr, env, ns));
(function() {
var bodyDisposers = [];
effect(function() { { var _c = bodyDisposers; for (var _i = 0; _i < _c.length; _i++) { var d = _c[_i]; d(); } }
bodyDisposers = [];
return tryCatch(function() { return (function() {
var frag = createFragment();
withIslandScope(function(disposable) { bodyDisposers.push(disposable);
return registerInScope(disposable); }, function() { return forEach(function(child) { return domAppend(frag, renderToDom(child, env, ns)); }, bodyExprs); });
domSetProp(container, "innerHTML", "");
return domAppend(container, frag);
})(); }, function(err) { return NIL; }); });
return registerInScope(function() { { var _c = bodyDisposers; for (var _i = 0; _i < _c.length; _i++) { var d = _c[_i]; d(); } }
return (bodyDisposers = []); });
})();
return container;
})(); };
// === Transpiled from engine ===
@@ -3114,6 +3138,11 @@ return (isSxTruthy((_batchDepth == 0)) ? (function() {
return state;
})(); };
// transition
var transition = function(pendingSig, thunk) { reset_b(pendingSig, true);
return scheduleIdle(function() { batch(thunk);
return reset_b(pendingSig, false); }); };
// =========================================================================
// Platform interface — DOM adapter (browser-only)
@@ -3406,6 +3435,11 @@ return (isSxTruthy((_batchDepth == 0)) ? (function() {
function promiseResolve(val) { return Promise.resolve(val); }
function promiseThen(p, onResolve, onReject) {
if (!p || !p.then) return p;
return onReject ? p.then(onResolve, onReject) : p.then(onResolve);
}
function promiseCatch(p, fn) { return p && p.catch ? p.catch(fn) : p; }
// --- Abort controllers ---
@@ -3849,6 +3883,10 @@ return (isSxTruthy((_batchDepth == 0)) ? (function() {
function errorMessage(e) {
return e && e.message ? e.message : String(e);
}
function scheduleIdle(fn) {
if (typeof requestIdleCallback !== "undefined") requestIdleCallback(fn);
else setTimeout(fn, 0);
}
function elementValue(el) { return el && el.value !== undefined ? el.value : NIL; }
function domAddListener(el, event, fn, opts) {

View File

@@ -14,7 +14,7 @@
// =========================================================================
var NIL = Object.freeze({ _nil: true, toString: function() { return "nil"; } });
var SX_VERSION = "2026-03-08T16:35:00Z";
var SX_VERSION = "2026-03-08T16:36:52Z";
function isNil(x) { return x === NIL || x === null || x === undefined; }
function isSxTruthy(x) { return x !== false && !isNil(x); }
@@ -1546,7 +1546,7 @@ return result; }, args);
var renderDomUnknownComponent = function(name) { return error((String("Unknown component: ") + String(name))); };
// RENDER_DOM_FORMS
var RENDER_DOM_FORMS = ["if", "when", "cond", "case", "let", "let*", "begin", "do", "define", "defcomp", "defisland", "defmacro", "defstyle", "defhandler", "map", "map-indexed", "filter", "for-each", "portal", "error-boundary"];
var RENDER_DOM_FORMS = ["if", "when", "cond", "case", "let", "let*", "begin", "do", "define", "defcomp", "defisland", "defmacro", "defstyle", "defhandler", "map", "map-indexed", "filter", "for-each", "portal", "error-boundary", "suspense"];
// render-dom-form?
var isRenderDomForm = function(name) { return contains(RENDER_DOM_FORMS, name); };
@@ -1604,7 +1604,7 @@ return result; }, args);
return domAppend(frag, val);
})(); }, coll);
return frag;
})() : (isSxTruthy((name == "filter")) ? renderToDom(trampoline(evalExpr(expr, env)), env, ns) : (isSxTruthy((name == "portal")) ? renderDomPortal(args, env, ns) : (isSxTruthy((name == "error-boundary")) ? renderDomErrorBoundary(args, env, ns) : (isSxTruthy((name == "for-each")) ? (function() {
})() : (isSxTruthy((name == "filter")) ? renderToDom(trampoline(evalExpr(expr, env)), env, ns) : (isSxTruthy((name == "portal")) ? renderDomPortal(args, env, ns) : (isSxTruthy((name == "error-boundary")) ? renderDomErrorBoundary(args, env, ns) : (isSxTruthy((name == "suspense")) ? renderDomSuspense(args, env, ns) : (isSxTruthy((name == "for-each")) ? (function() {
var f = trampoline(evalExpr(nth(expr, 1), env));
var coll = trampoline(evalExpr(nth(expr, 2), env));
var frag = createFragment();
@@ -1613,7 +1613,7 @@ return result; }, args);
return domAppend(frag, val);
})(); } }
return frag;
})() : renderToDom(trampoline(evalExpr(expr, env)), env, ns)))))))))))))); };
})() : renderToDom(trampoline(evalExpr(expr, env)), env, ns))))))))))))))); };
// render-lambda-dom
var renderLambdaDom = function(f, args, env, ns) { return (function() {
@@ -1805,6 +1805,30 @@ return (boundaryDisposers = []); });
})();
})(); };
// render-dom-suspense
var renderDomSuspense = function(args, env, ns) { return (function() {
var fallbackExpr = first(args);
var bodyExprs = rest(args);
var container = domCreateElement("div", NIL);
domSetAttr(container, "data-sx-suspense", "true");
domAppend(container, renderToDom(fallbackExpr, env, ns));
(function() {
var bodyDisposers = [];
effect(function() { { var _c = bodyDisposers; for (var _i = 0; _i < _c.length; _i++) { var d = _c[_i]; d(); } }
bodyDisposers = [];
return tryCatch(function() { return (function() {
var frag = createFragment();
withIslandScope(function(disposable) { bodyDisposers.push(disposable);
return registerInScope(disposable); }, function() { return forEach(function(child) { return domAppend(frag, renderToDom(child, env, ns)); }, bodyExprs); });
domSetProp(container, "innerHTML", "");
return domAppend(container, frag);
})(); }, function(err) { return NIL; }); });
return registerInScope(function() { { var _c = bodyDisposers; for (var _i = 0; _i < _c.length; _i++) { var d = _c[_i]; d(); } }
return (bodyDisposers = []); });
})();
return container;
})(); };
// === Transpiled from engine ===
@@ -3114,6 +3138,11 @@ return (isSxTruthy((_batchDepth == 0)) ? (function() {
return state;
})(); };
// transition
var transition = function(pendingSig, thunk) { reset_b(pendingSig, true);
return scheduleIdle(function() { batch(thunk);
return reset_b(pendingSig, false); }); };
// =========================================================================
// Platform interface — DOM adapter (browser-only)
@@ -3406,6 +3435,11 @@ return (isSxTruthy((_batchDepth == 0)) ? (function() {
function promiseResolve(val) { return Promise.resolve(val); }
function promiseThen(p, onResolve, onReject) {
if (!p || !p.then) return p;
return onReject ? p.then(onResolve, onReject) : p.then(onResolve);
}
function promiseCatch(p, fn) { return p && p.catch ? p.catch(fn) : p; }
// --- Abort controllers ---
@@ -3849,6 +3883,10 @@ return (isSxTruthy((_batchDepth == 0)) ? (function() {
function errorMessage(e) {
return e && e.message ? e.message : String(e);
}
function scheduleIdle(fn) {
if (typeof requestIdleCallback !== "undefined") requestIdleCallback(fn);
else setTimeout(fn, 0);
}
function elementValue(el) { return el && el.value !== undefined ? el.value : NIL; }
function domAddListener(el, event, fn, opts) {

View File

@@ -309,7 +309,8 @@
(define RENDER_DOM_FORMS
(list "if" "when" "cond" "case" "let" "let*" "begin" "do"
"define" "defcomp" "defisland" "defmacro" "defstyle" "defhandler"
"map" "map-indexed" "filter" "for-each" "portal" "error-boundary"))
"map" "map-indexed" "filter" "for-each" "portal"
"error-boundary" "suspense"))
(define render-dom-form?
(fn (name)
@@ -434,6 +435,10 @@
(= name "error-boundary")
(render-dom-error-boundary args env ns)
;; suspense — show fallback while resource is loading
(= name "suspense")
(render-dom-suspense args env ns)
;; for-each (render variant)
(= name "for-each")
(let ((f (trampoline (eval-expr (nth expr 1) env)))
@@ -823,6 +828,66 @@
container))))
;; --------------------------------------------------------------------------
;; render-dom-suspense — show fallback while resource is loading
;; --------------------------------------------------------------------------
;;
;; (suspense fallback-expr body...)
;;
;; Renders fallback-expr initially. When used with a resource signal,
;; an effect watches the resource state and swaps in the body content
;; once loading is complete. If the resource errors, renders the error.
;;
;; The simplest pattern: wrap a resource deref in suspense.
;;
;; (suspense
;; (div "Loading...")
;; (let ((data (get (deref user-resource) "data")))
;; (div (get data "name"))))
(define render-dom-suspense
(fn (args env ns)
(let ((fallback-expr (first args))
(body-exprs (rest args))
(container (dom-create-element "div" nil)))
(dom-set-attr container "data-sx-suspense" "true")
;; Render fallback immediately
(dom-append container (render-to-dom fallback-expr env ns))
;; Try to render body — if it works, replace fallback
;; The body typically derefs a resource signal, which triggers
;; an effect that re-renders when the resource resolves
(let ((body-disposers (list)))
(effect (fn ()
;; Dispose previous body renders
(for-each (fn (d) (d)) body-disposers)
(set! body-disposers (list))
;; Try rendering the body
(try-catch
(fn ()
(let ((frag (create-fragment)))
(with-island-scope
(fn (disposable)
(append! body-disposers disposable)
(register-in-scope disposable))
(fn ()
(for-each
(fn (child)
(dom-append frag (render-to-dom child env ns)))
body-exprs)))
;; Success — replace container content with body
(dom-set-prop container "innerHTML" "")
(dom-append container frag)))
(fn (err)
;; Body threw — keep showing fallback (or show error)
nil))))
;; Register cleanup
(register-in-scope
(fn ()
(for-each (fn (d) (d)) body-disposers)
(set! body-disposers (list)))))
container)))
;; --------------------------------------------------------------------------
;; Platform interface — DOM adapter
;; --------------------------------------------------------------------------

View File

@@ -449,6 +449,7 @@ class JSEmitter:
"dom-focus": "domFocus",
"try-catch": "tryCatch",
"error-message": "errorMessage",
"schedule-idle": "scheduleIdle",
"element-value": "elementValue",
"validate-for-request": "validateForRequest",
"with-transition": "withTransition",
@@ -3031,6 +3032,11 @@ PLATFORM_ORCHESTRATION_JS = """
function promiseResolve(val) { return Promise.resolve(val); }
function promiseThen(p, onResolve, onReject) {
if (!p || !p.then) return p;
return onReject ? p.then(onResolve, onReject) : p.then(onResolve);
}
function promiseCatch(p, fn) { return p && p.catch ? p.catch(fn) : p; }
// --- Abort controllers ---
@@ -3474,6 +3480,10 @@ PLATFORM_ORCHESTRATION_JS = """
function errorMessage(e) {
return e && e.message ? e.message : String(e);
}
function scheduleIdle(fn) {
if (typeof requestIdleCallback !== "undefined") requestIdleCallback(fn);
else setTimeout(fn, 0);
}
function elementValue(el) { return el && el.value !== undefined ? el.value : NIL; }
function domAddListener(el, event, fn, opts) {

View File

@@ -438,3 +438,29 @@
(fn (data) (reset! state (dict "loading" false "data" data "error" nil)))
(fn (err) (reset! state (dict "loading" false "data" nil "error" err))))
state)))
;; ==========================================================================
;; 16. Transitions — non-urgent signal updates
;; ==========================================================================
;;
;; Transitions mark updates as non-urgent. The thunk's signal writes are
;; deferred to an idle callback, keeping the UI responsive during expensive
;; computations.
;;
;; (transition pending-signal thunk)
;;
;; Sets pending-signal to true, schedules thunk via requestIdleCallback
;; (or setTimeout 0 as fallback), then sets pending-signal to false when
;; the thunk completes. Signal writes inside the thunk are batched.
;;
;; Platform interface required:
;; (schedule-idle thunk) → void — requestIdleCallback or setTimeout(fn, 0)
(define transition
(fn (pending-sig thunk)
(reset! pending-sig true)
(schedule-idle
(fn ()
(batch thunk)
(reset! pending-sig false)))))

View File

@@ -149,7 +149,19 @@
(td :class "px-3 py-2 text-stone-700" "Phase 2 remaining")
(td :class "px-3 py-2 text-stone-500 font-medium" "P2")
(td :class "px-3 py-2 font-mono text-xs text-stone-500"
(a :href "/reactive-islands/phase2" :sx-get "/reactive-islands/phase2" :sx-target "#main-panel" :sx-select "#main-panel" :sx-swap "outerHTML" :sx-push-url "true" :class "text-violet-700 underline" "Error boundaries, suspense, transitions")))))))))
(a :href "/reactive-islands/phase2" :sx-get "/reactive-islands/phase2" :sx-target "#main-panel" :sx-select "#main-panel" :sx-swap "outerHTML" :sx-push-url "true" :class "text-violet-700 underline" "Error boundaries, suspense, transitions")))
(tr :class "border-b border-stone-100"
(td :class "px-3 py-2 text-stone-700" "Error boundaries")
(td :class "px-3 py-2 text-green-700 font-medium" "Done")
(td :class "px-3 py-2 font-mono text-xs text-stone-500" "adapter-dom.sx: error-boundary render-dom form"))
(tr :class "border-b border-stone-100"
(td :class "px-3 py-2 text-stone-700" "Suspense + resource")
(td :class "px-3 py-2 text-green-700 font-medium" "Done")
(td :class "px-3 py-2 font-mono text-xs text-stone-500" "adapter-dom.sx, signals.sx"))
(tr
(td :class "px-3 py-2 text-stone-700" "Transitions")
(td :class "px-3 py-2 text-green-700 font-medium" "Done")
(td :class "px-3 py-2 font-mono text-xs text-stone-500" "signals.sx: transition, schedule-idle"))))))))
;; ---------------------------------------------------------------------------
;; Live demo islands
@@ -407,12 +419,8 @@
(p :class "mt-2 text-sm text-stone-500" "Run: " (code "python3 shared/sx/tests/run.py signals")))
(~doc-section :title "What's next" :id "next"
(p "Phase 1 and Phase 2 P0/P1 features are complete. The remaining P2 features are optional enhancements:")
(ul :class "space-y-2 text-stone-600 list-disc pl-5"
(li (strong "Error boundaries") " — catch errors in island subtrees, render fallback UI")
(li (strong "Suspense + resource") " — async-aware rendering with loading states")
(li (strong "Transitions") " — non-urgent signal updates for expensive re-renders"))
(p "See the " (a :href "/reactive-islands/phase2" :sx-get "/reactive-islands/phase2" :sx-target "#main-panel" :sx-select "#main-panel" :sx-swap "outerHTML" :sx-push-url "true" :class "text-violet-700 underline" "Phase 2 plan") " for details."))))
(p "Phase 1 and Phase 2 are complete. The reactive islands system now includes: signals, effects, computed values, islands, disposal, stores, event bridges, reactive DOM rendering, input binding, keyed reconciliation, refs, portals, error boundaries, suspense, resource, and transitions.")
(p "See the " (a :href "/reactive-islands/phase2" :sx-get "/reactive-islands/phase2" :sx-target "#main-panel" :sx-select "#main-panel" :sx-swap "outerHTML" :sx-push-url "true" :class "text-violet-700 underline" "Phase 2 plan") " for the full feature list and design details."))))
;; ---------------------------------------------------------------------------
@@ -660,11 +668,14 @@
(td :class "px-3 py-2 text-stone-700" "Refs + portals")
(td :class "px-3 py-2 text-green-700 font-medium" "Done")
(td :class "px-3 py-2 text-stone-700" "ref, ref-get, ref-set!, :ref, portal"))
(tr :class "border-b border-stone-100"
(td :class "px-3 py-2 text-stone-700" "Error boundaries + suspense")
(td :class "px-3 py-2 text-green-700 font-medium" "Done")
(td :class "px-3 py-2 text-stone-700" "error-boundary, suspense, resource"))
(tr
(td :class "px-3 py-2 text-stone-700" "Phase 2 remaining")
(td :class "px-3 py-2 text-violet-700 font-medium"
(a :href "/reactive-islands/phase2" :sx-get "/reactive-islands/phase2" :sx-target "#main-panel" :sx-select "#main-panel" :sx-swap "outerHTML" :sx-push-url "true" :class "text-violet-700 underline" "Details →"))
(td :class "px-3 py-2 text-stone-700" "Error boundaries, suspense, transitions"))))))
(td :class "px-3 py-2 text-stone-700" "Transitions")
(td :class "px-3 py-2 text-green-700 font-medium" "Done")
(td :class "px-3 py-2 text-stone-700" "signals.sx: transition, schedule-idle"))))))
(~doc-section :title "Design Principles" :id "principles"
(ol :class "space-y-3 text-stone-600 list-decimal list-inside"
@@ -720,17 +731,17 @@
(tr :class "border-b border-stone-100"
(td :class "px-3 py-2 text-stone-700" "Error boundaries")
(td :class "px-3 py-2 text-stone-500 text-xs" "componentDidCatch")
(td :class "px-3 py-2 text-stone-500 font-medium" "P2")
(td :class "px-3 py-2 text-green-700 font-medium" "Done")
(td :class "px-3 py-2 font-mono text-xs text-stone-500" "adapter-dom.sx"))
(tr :class "border-b border-stone-100"
(td :class "px-3 py-2 text-stone-700" "Suspense")
(td :class "px-3 py-2 text-stone-500 text-xs" "Suspense + lazy")
(td :class "px-3 py-2 text-stone-500 font-medium" "P2")
(td :class "px-3 py-2 text-green-700 font-medium" "Done")
(td :class "px-3 py-2 font-mono text-xs text-stone-500" "adapter-dom.sx, signals.sx"))
(tr
(td :class "px-3 py-2 text-stone-700" "Transitions")
(td :class "px-3 py-2 text-stone-500 text-xs" "startTransition")
(td :class "px-3 py-2 text-stone-500 font-medium" "P2")
(td :class "px-3 py-2 text-green-700 font-medium" "Done")
(td :class "px-3 py-2 font-mono text-xs text-stone-500" "signals.sx"))))))
;; -----------------------------------------------------------------------