Add Syndicate.suspend

packages/core/src/runtime/actor.ts

@@ -282,6 +282,30 @@ export class Facet {
     }
 }
 
+export function suspend(asyncFn: (resume: <T>(v: T) => T) => void) {
+    const facet = Turn.activeFacet;
+
+    const resume = <T>(v: T) => {
+        if (!facet.actor.space.isRunning()) {
+            throw new Error('Cannot resume into inactive actor space'); // TODO
+        }
+        const t = Turn.___new(facet);
+        queueMicrotask(() => {
+            try {
+                facet.actor.repairDataflowGraph();
+                t.deliver();
+            } catch (err) {
+                Turn.for(facet.actor.root, () => facet.actor._terminateWith({ ok: false, err }));
+            }
+            if (Turn.active === t) Turn.active = void 0 as unknown as Turn;
+        });
+        Turn.active = t;
+        return v;
+    };
+
+    return asyncFn(resume);
+}
+
 export const STOP_ON_RETRACT = Symbol('stop-on-retract'); // NB. NOT A GLOBAL SYMBOL
 
 export class StopOnRetract implements Partial<Entity> {
@@ -341,6 +365,10 @@ export class Turn {
         }
     }
 
+    static ___new(facet: Facet): Turn {
+        return new Turn(facet);
+    }
+
     private constructor(facet: Facet, queues = new Map<Actor, StructuredTask<TaskAction>[]>()) {
         this._activeFacet = facet;
         this.queues = queues;