extendable if-else blocks

Author: CST1229

src/blocks/scratch3_control.js

@@ -32,6 +32,8 @@ class Scratch3ControlBlocks {
             control_wait_until: this.waitUntil,
             control_if: this.if,
             control_if_else: this.ifElse,
+            control_if_extendable: this.ifExtendable,
+            control_if_else_extendable: this.ifElseExtendable,
             control_stop: this.stop,
             control_create_clone_of: this.createClone,
             control_delete_this_clone: this.deleteClone,
@@ -137,6 +139,27 @@ class Scratch3ControlBlocks {
         }
     }
 
+    ifExtendable (args, util) {
+        const argCount = args.BRANCHES;
+        for (let i = 0; i < argCount; i++) {
+            if (Cast.toBoolean(args[`BRANCHES_${i}_CONDITION`])) {
+                util.startBranch(`BRANCHES_${i}_BRANCH`);
+                return;
+            }
+        }
+    }
+
+    ifElseExtendable (args, util) {
+        const argCount = args.BRANCHES;
+        for (let i = 0; i < argCount; i++) {
+            if (Cast.toBoolean(args[`BRANCHES_${i}_CONDITION`])) {
+                util.startBranch(`BRANCHES_${i}_BRANCH`);
+                return;
+            }
+        }
+        util.startBranch('ELSE');
+    }
+
     stop (args, util) {
         const option = args.STOP_OPTION;
         if (option === 'all') {