feat: pull in Rachel's changes from the other repo (#23)

Author: BeksOmega

package-lock.json

@@ -67,5 +67,8 @@
   },
   "eslintConfig": {
     "extends": "@blockly/eslint-config"
+  },
+  "dependencies": {
+    "@blockly/keyboard-navigation": "^0.6.2"
   }
 }

package.json

@@ -0,0 +1,119 @@
+
+/**
+ * @license
+ * Copyright 2024 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { LineCursor } from '@blockly/keyboard-navigation';
+import { ASTNode } from 'blockly';
+
+export class ExtendedLineCursor extends LineCursor {
+
+    nextSibling() {
+        const curNode = this.getCurNode();
+        if (!curNode) {
+          return null;
+        }
+        let newNode = null;
+        switch (curNode.type) {
+          case ASTNode.types.STACK: {
+            newNode = curNode.navigateBetweenStacks(true);
+            break;
+          }
+          case ASTNode.types.WORKSPACE: {
+            break;
+          }
+          default: {
+            const block = curNode.getSourceBlock();
+            const nextBlock = block.getNextBlock();
+            newNode = ASTNode.createBlockNode(nextBlock);
+            break;
+          }
+        }
+    
+        if (newNode) {
+          this.setCurNode(newNode);
+        }
+        return newNode;
+      }
+    
+      previousSibling() {
+    
+        const curNode = this.getCurNode();
+        if (!curNode) {
+          return null;
+        }
+        let newNode = null;
+        switch (curNode.type) {
+          case ASTNode.types.STACK: {
+            newNode = curNode.navigateBetweenStacks(false);
+            break;
+          }
+          case ASTNode.types.WORKSPACE: {
+            break;
+          }
+          default: {
+            const block = curNode.getSourceBlock();
+            // TODO: Decide what this should do if the source block is
+            // the first block inside a statement input.
+            // TODO: Decide what this should do if the source block
+            // has an output instead of a previous.
+            const prevBlock = block.getPreviousBlock();
+            newNode = ASTNode.createBlockNode(prevBlock);
+            break;
+          }
+        }
+    
+        if (newNode) {
+          this.setCurNode(newNode);
+        }
+        return newNode;
+    
+      }
+    
+    contextOut() {
+      const curNode = this.getCurNode();
+      if (!curNode) {
+        return null;
+      }
+
+      // Returns null at the workspace level.
+      // TODO: Decide where the cursor goes from the workspace level.
+      let newNode = curNode.out();  
+      if (newNode) {
+        this.setCurNode(newNode);
+      }
+      return newNode;
+    }
+
+    contextIn() {
+      let curNode = this.getCurNode();
+      if (!curNode) {
+        return null;
+      }
+      // If we are on a previous or output connection, go to the block level
+      // before performing next operation.
+      if (
+        curNode.getType() === ASTNode.types.PREVIOUS ||
+        curNode.getType() === ASTNode.types.OUTPUT
+      ) {
+        curNode = curNode.next();
+      }
+      const newNode = curNode?.in() ?? null;
+  
+      if (newNode) {
+        this.setCurNode(newNode);
+      }
+      return newNode;
+    }
+}
+
+export function installCursor(markerManager) {
+    const oldCurNode = markerManager.getCursor().getCurNode();
+    const lineCursor = new ExtendedLineCursor();
+    markerManager.setCursor(lineCursor);
+    if (oldCurNode) {
+        markerManager.getCursor().setCurNode(oldCurNode);
+    }
+}