Add Lily/Cast extension (#605)

extensions/Lily/Cast.js

@@ -0,0 +1,73 @@
+(function (Scratch) {
+  'use strict';
+
+  const Cast = Scratch.Cast;
+
+  class CastUtil {
+    getInfo() {
+      return {
+        id: 'lmsCast',
+        name: 'Cast',
+        blocks: [
+          {
+            opcode: 'toType',
+            blockType: Scratch.BlockType.REPORTER,
+            text: 'cast [INPUT] to [TYPE]',
+            allowDropAnywhere: true,
+            disableMonitor: true,
+            arguments: {
+              INPUT: {
+                type: Scratch.ArgumentType.STRING,
+                defaultValue: 'apple'
+              },
+              TYPE: {
+                type: Scratch.ArgumentType.STRING,
+                menu: 'type'
+              }
+            }
+          },
+          {
+            opcode: 'typeOf',
+            blockType: Scratch.BlockType.REPORTER,
+            text: 'type of [INPUT]',
+            disableMonitor: true,
+            arguments: {
+              INPUT: {
+                type: Scratch.ArgumentType.STRING,
+                defaultValue: 'apple'
+              }
+            }
+          }
+        ],
+        menus: {
+          type: {
+            acceptReporters: true,
+            items: ['number', 'string', 'boolean', 'default']
+          }
+        }
+      };
+    }
+
+    toType(args) {
+      const input = args.INPUT;
+      switch (args.TYPE) {
+        case ('number'): return Cast.toNumber(input);
+        case ('string'): return Cast.toString(input);
+        case ('boolean'): return Cast.toBoolean(input);
+        default: return input;
+      }
+    }
+
+    typeOf(args) {
+      const input = args.INPUT;
+      switch (typeof input) {
+        case ('number'): return 'number';
+        case ('string'): return 'string';
+        case ('boolean'): return 'boolean';
+        default: return '';
+      }
+    }
+  }
+
+  Scratch.extensions.register(new CastUtil());
+})(Scratch);