feat(web): add spur variants specialized for each edit type 🚂

web/src/engine/predictive-text/worker-thread/src/main/correction/deletion-quotient-spur.ts

@@ -0,0 +1,44 @@
+/**
+ * Keyman is copyright (C) SIL Global. MIT License.
+ *
+ * Created by jahorton on 2026-02-03
+ *
+ * This file adds a SearchQuotientSpur variant modeling deletion of the corresponding
+ * keystroke.
+ */
+
+import { LexicalModelTypes } from "@keymanapp/common-types";
+
+import { SearchNode } from "./distance-modeler.js";
+import { PathInputProperties, SearchQuotientNode } from "./search-quotient-node.js";
+import { SearchQuotientSpur } from "./search-quotient-spur.js";
+
+import Distribution = LexicalModelTypes.Distribution;
+import ProbabilityMass = LexicalModelTypes.ProbabilityMass;
+import Transform = LexicalModelTypes.Transform;
+
+export class DeletionQuotientSpur extends SearchQuotientSpur {
+  public readonly insertLength: number = 0;
+  public readonly leftDeleteLength: number = 0;
+
+  constructor(
+    parentNode: SearchQuotientNode,
+    inputs: Distribution<Readonly<Transform>>,
+    inputSource: PathInputProperties | ProbabilityMass<Transform>
+  ) {
+    super(parentNode, inputs, inputSource, parentNode.codepointLength);
+  }
+
+  construct(parentNode: SearchQuotientNode, inputs: ProbabilityMass<Readonly<Transform>>[], inputSource: PathInputProperties): this {
+    return new DeletionQuotientSpur(parentNode, inputs, inputSource) as this;
+  }
+
+  protected buildEdgesForNodes(baseNodes: ReadonlyArray<SearchNode>): SearchNode[] {
+    return baseNodes.flatMap((n) => n.buildDeletionEdges(this.inputs, this.spaceId));
+  }
+
+  get edgeKey(): string {
+    const baseKey = super.edgeKey;
+    return `${baseKey}DEL`;
+  }
+}

web/src/engine/predictive-text/worker-thread/src/main/correction/insertion-quotient-spur.ts

@@ -0,0 +1,41 @@
+/**
+ * Keyman is copyright (C) SIL Global. MIT License.
+ *
+ * Created by jahorton on 2026-02-03
+ *
+ * This file adds a SearchQuotientSpur variant modeling insertion of
+ * lexical-entry prefix characters - an operation with no corresponding
+ * keystroke.
+ */
+
+import { SearchNode } from "./distance-modeler.js";
+import { SearchQuotientNode } from "./search-quotient-node.js";
+import { SearchQuotientSpur } from "./search-quotient-spur.js";
+
+export class InsertionQuotientSpur extends SearchQuotientSpur {
+  public readonly insertLength = 1;
+  public readonly leftDeleteLength = 0;
+
+  constructor(
+    parentNode: SearchQuotientNode
+  ) {
+    super(parentNode, null, null, parentNode.codepointLength + 1);
+  }
+
+  construct(parentNode: SearchQuotientNode): this {
+    return new InsertionQuotientSpur(parentNode) as this;
+  }
+
+  protected buildEdgesForNodes(baseNodes: ReadonlyArray<SearchNode>): SearchNode[] {
+    // Note that .buildInsertionEdges will not extend any nodes reached by empty-input
+    // or by deletions.
+    return baseNodes.flatMap((n) => n.buildInsertionEdges());
+  }
+
+  get edgeKey(): string {
+    return `SR[${this.parentNode.sourceRangeKey}]L${this.codepointLength}INS`;
+    // How will this differentiate from other cases?
+    // ... sourceRangeKey + codepointLength + insert count?
+    return '';
+  }
+}

web/src/engine/predictive-text/worker-thread/src/main/correction/search-quotient-spur.ts

@@ -41,7 +41,7 @@ export abstract class SearchQuotientSpur extends SearchQuotientNode {
   readonly inputs?: Distribution<Transform>;
   readonly inputSource?: PathInputProperties;
 
-  private parentNode: SearchQuotientNode;
+  protected readonly parentNode: SearchQuotientNode;
   readonly spaceId: number;
 
   readonly inputCount: number;
@@ -511,9 +511,7 @@ export abstract class SearchQuotientSpur extends SearchQuotientNode {
    *    ancestry properly handle quotient-path variance in unit tests.
    */
   get edgeKey(): string {
-    const inputSrc = this.inputSource;
-    const segment = inputSrc.segment;
-    return `E${inputSrc.subsetId}:${segment.start}${segment.end !== undefined ? `-${segment.end}` : ''}`;
+    return `E${this.inputSource?.subsetId ?? ''}:${this.splitClusteringKey}`;
   }
 
   isSameNode(space: SearchQuotientNode): boolean {
@@ -540,11 +538,7 @@ export abstract class SearchQuotientSpur extends SearchQuotientNode {
 
   // Used to identify cluster-compatible components of SearchPaths during SearchCluster split operations.
   get splitClusteringKey(): string {
-    const pathSrc = this.inputSource;
-    if(!pathSrc) {
-      return '';
-    }
-
-    return `${pathSrc.segment.start}${pathSrc.segment.end == undefined ? '' : `-${pathSrc.segment.end}`}`;
+    const spurSeg = this.inputSource?.segment;
+    return `${spurSeg?.start ?? 0}${spurSeg?.end == undefined ? '' : `-${spurSeg.end}`}`;
   }
 }

web/src/engine/predictive-text/worker-thread/src/main/correction/substitution-quotient-spur.ts

@@ -0,0 +1,47 @@
+/**
+ * Keyman is copyright (C) SIL Global. MIT License.
+ *
+ * Created by jahorton on 2026-02-03
+ *
+ * This file adds a SearchQuotientSpur variant modeling match & substitute edit
+ * operations in regard to the corresponding keystroke.
+ */
+
+import { LexicalModelTypes } from "@keymanapp/common-types";
+import { KMWString } from "@keymanapp/web-utils";
+
+import { SearchNode } from "./distance-modeler.js";
+import { PathInputProperties, SearchQuotientNode } from "./search-quotient-node.js";
+import { SearchQuotientSpur } from "./search-quotient-spur.js";
+
+import Distribution = LexicalModelTypes.Distribution;
+import ProbabilityMass = LexicalModelTypes.ProbabilityMass;
+import Transform = LexicalModelTypes.Transform;
+
+export class SubstitutionQuotientSpur extends SearchQuotientSpur {
+  public insertLength: number;
+  public leftDeleteLength: number;
+
+  constructor(
+    parentNode: SearchQuotientNode,
+    inputs: Distribution<Readonly<Transform>>,
+    inputSource: PathInputProperties | ProbabilityMass<Transform>
+  ) {
+    // Compute this SearchPath's codepoint length & edge length.
+    const inputSample = inputs?.[0].sample ?? { insert: '', deleteLeft: 0 };
+    const insertLength = KMWString.length(inputSample.insert);
+    super(parentNode, inputs, inputSource, parentNode.codepointLength + insertLength - inputSample.deleteLeft);
+
+    // Compute this SearchPath's codepoint length & edge length.
+    this.insertLength = insertLength;
+    this.leftDeleteLength = inputSample.deleteLeft;
+  }
+
+  construct(parentNode: SearchQuotientNode, inputs: ProbabilityMass<Readonly<Transform>>[], inputSource: PathInputProperties): this {
+    return new SubstitutionQuotientSpur(parentNode, inputs, inputSource) as this;
+  }
+
+  protected buildEdgesForNodes(baseNodes: ReadonlyArray<SearchNode>): SearchNode[] {
+    return baseNodes.flatMap((n) => n.buildSubstitutionEdges(this.inputs, this.spaceId));
+  }
+}

web/src/engine/predictive-text/worker-thread/src/main/test-index.ts

@@ -5,6 +5,9 @@ export * from './correction/context-tokenization.js';
 export { ContextTracker } from './correction/context-tracker.js';
 export { ContextTransition } from './correction/context-transition.js';
 export * from './correction/distance-modeler.js';
+export * from './correction/deletion-quotient-spur.js';
+export * from './correction/insertion-quotient-spur.js';
+export * from './correction/substitution-quotient-spur.js';
 export * from './correction/search-quotient-cluster.js';
 export * from './correction/search-quotient-spur.js';
 export * from './correction/search-quotient-node.js';