Merge pull request #963 from towerofnix/foreach-vm

Implement for-each block

src/blocks/scratch3_control.js

@@ -17,6 +17,7 @@ class Scratch3ControlBlocks {
         return {
             control_repeat: this.repeat,
             control_repeat_until: this.repeatUntil,
+            control_for_each: this.forEach,
             control_forever: this.forever,
             control_wait: this.wait,
             control_wait_until: this.waitUntil,
@@ -61,6 +62,21 @@ class Scratch3ControlBlocks {
         }
     }
 
+    forEach (args, util) {
+        const variable = util.target.lookupOrCreateVariable(
+            args.VARIABLE.id, args.VARIABLE.name);
+
+        if (typeof util.stackFrame.index === 'undefined') {
+            util.stackFrame.index = 0;
+        }
+
+        if (util.stackFrame.index < Number(args.VALUE)) {
+            util.stackFrame.index++;
+            variable.value = util.stackFrame.index;
+            util.startBranch(1, true);
+        }
+    }
+
     waitUntil (args, util) {
         const condition = Cast.toBoolean(args.CONDITION);
         if (!condition) {

src/serialization/sb2_specmap.js

@@ -768,6 +768,24 @@ const specMap = {
             }
         ]
     },
+    'doForLoop': {
+        opcode: 'control_for_each',
+        argMap: [
+            {
+                type: 'field',
+                fieldName: 'VARIABLE'
+            },
+            {
+                type: 'input',
+                inputOp: 'text',
+                inputName: 'VALUE'
+            },
+            {
+                type: 'input',
+                inputName: 'SUBSTACK'
+            }
+        ]
+    },
     'stopScripts': {
         opcode: 'control_stop',
         argMap: [

test/unit/blocks_control.js

@@ -52,6 +52,47 @@ test('repeatUntil', t => {
     t.end();
 });
 
+test('forEach', t => {
+    const rt = new Runtime();
+    const c = new Control(rt);
+
+    const variableValues = [];
+    const variable = {value: 0};
+    let value;
+    const util = {
+        stackFrame: Object.create(null),
+        target: {
+            lookupOrCreateVariable: function () {
+                return variable;
+            }
+        },
+        startBranch: function () {
+            variableValues.push(variable.value);
+            c.forEach({VARIABLE: {}, VALUE: value}, util);
+        }
+    };
+
+    // for each (variable) in "5"
+    // ..should yield variable values 1, 2, 3, 4, 5
+    util.stackFrame = Object.create(null);
+    variableValues.splice(0);
+    variable.value = 0;
+    value = '5';
+    c.forEach({VARIABLE: {}, VALUE: value}, util);
+    t.deepEqual(variableValues, [1, 2, 3, 4, 5]);
+
+    // for each (variable) in 4
+    // ..should yield variable values 1, 2, 3, 4
+    util.stackFrame = Object.create(null);
+    variableValues.splice(0);
+    variable.value = 0;
+    value = 4;
+    c.forEach({VARIABLE: {}, VALUE: value}, util);
+    t.deepEqual(variableValues, [1, 2, 3, 4]);
+
+    t.end();
+});
+
 test('forever', t => {
     const rt = new Runtime();
     const c = new Control(rt);