Add signal interaction trigger for extension component signals

Documentation/extensions/contract.md

@@ -136,3 +136,9 @@ The subject supplies the definition, the properties it mounts with, different pr
 
 - [Screenplay screens](https://github.com/Cratis/Screenplay/blob/main/Documentation/screenplay/screens.md): placing a component on a screen.
 - [Stage custom packages](https://github.com/Cratis/Stage/blob/main/Documentation/reference/custom-packages.md): how Stage loads packages at runtime. Hosting extension components is tracked in [Cratis/Stage#1070](https://github.com/Cratis/Stage/issues/1070) and the language support in [Cratis/Screenplay#1255](https://github.com/Cratis/Screenplay/issues/1255).
+
+## Binding a raised signal to a screen interaction
+
+A screen handles a signal with `on <signal>`. Scene models that binding as a `SignalInteractionTrigger`, which carries only the `signalName` as the component's contract declares it (`@cratis/scene.model`, `Cratis.Scene.Model.Interactions`). It serializes as `{ "signalName": "succeeded" }` in an interaction binding's `trigger`, next to `kind`, `eventName`, `seconds` and `triggerName` triggers; the other trigger kinds are unchanged.
+
+When a component raises a signal, the host collects the behaviors attached to that component and resolves them with `resolveSignalBehaviors(attachments, signalName)` from `@cratis/scene.engine`. The result is in the same deterministic order as other triggers. A signal trigger never matches an application trigger of the same name, and the reverse.

Documentation/glossary.md

@@ -36,6 +36,7 @@ is what makes an interaction that names nothing real a diagnostic instead of a d
 | --- | --- |
 | **Interaction trigger** | What starts an interaction — a click, a submit, a screen becoming live, an observed domain event, an elapsed interval, or a declared application trigger firing. Anonymous: it exists only inside a behavior. |
 | **Application trigger** | Screenplay's declared top-level signal consumed by backend reactions. A different concept with a similar name — an interaction may `raise` one, which is how the two connect. |
+| **Signal trigger** | An interaction trigger started by an extension component raising a signal its contract declares (`on <signal>`). It is named by the signal alone, belongs to the component the behavior is attached to, and is resolved with `resolveSignalBehaviors`. Not an application trigger, even when the names match. |
 | **Action** | One declarative effect: execute a command, navigate, open or close a dialog, refresh a query, set state, notify, confirm, raise. |
 | **Continuation** | The `on success` / `on failure` / `on result` actions that run after an action that can fail. |
 | **Behavior** | A bundle of interaction-trigger-to-action bindings, attachable to an element, form, screen, template, layout, module or feature. Anonymous when written inline; named when reusable. Attachments are additive — a template's behavior and an element's both run. |

Source/DotNET/Model/Interactions/InteractionTrigger.cs

@@ -18,4 +18,5 @@ namespace Cratis.Scene.Model.Interactions;
 [JsonDerivedType(typeof(EventInteractionTrigger))]
 [JsonDerivedType(typeof(IntervalInteractionTrigger))]
 [JsonDerivedType(typeof(ApplicationTriggerInteractionTrigger))]
+[JsonDerivedType(typeof(SignalInteractionTrigger))]
 public abstract record InteractionTrigger;

Source/DotNET/Model/Interactions/SignalInteractionTrigger.cs

@@ -0,0 +1,10 @@
+// Copyright (c) Cratis. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+namespace Cratis.Scene.Model.Interactions;
+
+/// <summary>
+/// Represents an interaction started by an extension component raising a signal its contract declares.
+/// </summary>
+/// <param name="SignalName">The signal the component raised, as its contract names it.</param>
+public record SignalInteractionTrigger(string SignalName) : InteractionTrigger;

Source/JavaScript/engine/for_resolveBehaviors/when_resolving_additive_attachments.ts

@@ -2,7 +2,7 @@
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
 import { Behavior, InteractionActionKind, InteractionTriggerKind } from '@cratis/scene.model';
-import { BehaviorAttachment, resolveApplicationTriggerBehaviors, resolveBehaviors } from '../resolveBehaviors';
+import { BehaviorAttachment, resolveApplicationTriggerBehaviors, resolveBehaviors, resolveSignalBehaviors } from '../resolveBehaviors';
 
 const behavior = (name: string | undefined, kind: InteractionTriggerKind, order?: number): Behavior => ({
     name,
@@ -94,6 +94,26 @@ describe('when resolving additive attachments', () => {
         resolved.should.have.lengthOf(1);
     });
 
+    it('should resolve a raised signal separately from an application trigger of the same name', () => {
+        const attachments: BehaviorAttachment[] = [
+            {
+                level: 'component',
+                behaviors: [
+                    {
+                        bindings: [
+                            { trigger: { signalName: 'succeeded' } as never, actions: [] },
+                            { trigger: { signalName: 'failed' } as never, actions: [] },
+                            { trigger: { triggerName: 'succeeded' } as never, actions: [] },
+                        ],
+                    },
+                ],
+            },
+        ];
+
+        resolveSignalBehaviors(attachments, 'succeeded').should.have.lengthOf(1);
+        resolveApplicationTriggerBehaviors(attachments, 'succeeded').should.have.lengthOf(1);
+    });
+
     it('should tolerate an attachment with no behaviors at all', () => {
         resolveBehaviors([{ level: 'element', behaviors: [] }], InteractionTriggerKind.Click).should.be.empty;
     });

Source/JavaScript/engine/resolveBehaviors.ts

@@ -100,6 +100,20 @@ export function resolveApplicationTriggerBehaviors(attachments: BehaviorAttachme
     return collect(attachments, trigger => (trigger as { triggerName?: string }).triggerName === triggerName);
 }
 
+/**
+ * Collects the bindings that respond to an extension component raising a signal (`on <signal>`).
+ *
+ * Pass the attachments of the component that raised it: a signal belongs to its component, so the name is not
+ * qualified and an application trigger of the same name is never matched.
+ *
+ * @param attachments The attachment levels, outermost first.
+ * @param signalName The signal the component raised, as its contract names it.
+ * @returns The bindings to run, in order.
+ */
+export function resolveSignalBehaviors(attachments: BehaviorAttachment[], signalName: string): ResolvedBinding[] {
+    return collect(attachments, trigger => (trigger as { signalName?: string }).signalName === signalName);
+}
+
 /**
  * Collects the bindings that respond to a modeled domain event being observed.
  *

Source/JavaScript/model/interactions/SignalInteractionTrigger.ts

@@ -0,0 +1,16 @@
+// Copyright (c) Cratis. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+import { InteractionTrigger } from './InteractionTrigger';
+
+/**
+ * An interaction started by an extension component raising a signal its contract declares (`on <signal>`).
+ *
+ * The signal belongs to the component the behavior is attached to, so the name is not qualified. It is a different
+ * concept from an application trigger, which a declared `trigger <Name>` names and a backend reaction can consume.
+ */
+export interface SignalInteractionTrigger extends InteractionTrigger {
+    signalName: string;
+}
+
+export const SignalInteractionTriggerPropertyNames: (keyof SignalInteractionTrigger)[] = ['signalName'];

Source/JavaScript/model/interactions/index.ts

@@ -8,6 +8,7 @@ export * from './BuiltInInteractionTrigger';
 export * from './EventInteractionTrigger';
 export * from './IntervalInteractionTrigger';
 export * from './ApplicationTriggerInteractionTrigger';
+export * from './SignalInteractionTrigger';
 export * from './InteractionMessage';
 export * from './InteractionArgument';
 export * from './InteractionActionKind';

scene-model-shape.json

@@ -409,6 +409,9 @@
     "ApplicationTriggerInteractionTrigger": [
       "triggerName"
     ],
+    "SignalInteractionTrigger": [
+      "signalName"
+    ],
     "InteractionAction": [
       "kind",
       "arguments",