First cut at turning lists into typed variables

src/blocks/scratch3_data.js

@@ -52,8 +52,8 @@ class Scratch3DataBlocks {
         // If it is, report contents joined together with no separator.
         // If it's not, report contents joined together with a space.
         let allSingleLetters = true;
-        for (let i = 0; i < list.contents.length; i++) {
+        for (let i = 0; i < list.value.length; i++) {
-            const listItem = list.contents[i];
+            const listItem = list.value[i];
             if (!((typeof listItem === 'string') &&
                   (listItem.length === 1))) {
                 allSingleLetters = false;
@@ -61,73 +61,73 @@ class Scratch3DataBlocks {
             }
         }
         if (allSingleLetters) {
-            return list.contents.join('');
+            return list.value.join('');
         }
-        return list.contents.join(' ');
+        return list.value.join(' ');
 
     }
 
     addToList (args, util) {
         const list = util.target.lookupOrCreateList(args.LIST);
-        list.contents.push(args.ITEM);
+        list.value.push(args.ITEM);
     }
 
     deleteOfList (args, util) {
         const list = util.target.lookupOrCreateList(args.LIST);
-        const index = Cast.toListIndex(args.INDEX, list.contents.length);
+        const index = Cast.toListIndex(args.INDEX, list.value.length);
         if (index === Cast.LIST_INVALID) {
             return;
         } else if (index === Cast.LIST_ALL) {
-            list.contents = [];
+            list.value = [];
             return;
         }
-        list.contents.splice(index - 1, 1);
+        list.value.splice(index - 1, 1);
     }
 
     insertAtList (args, util) {
         const item = args.ITEM;
         const list = util.target.lookupOrCreateList(args.LIST);
-        const index = Cast.toListIndex(args.INDEX, list.contents.length + 1);
+        const index = Cast.toListIndex(args.INDEX, list.value.length + 1);
         if (index === Cast.LIST_INVALID) {
             return;
         }
-        list.contents.splice(index - 1, 0, item);
+        list.value.splice(index - 1, 0, item);
     }
 
     replaceItemOfList (args, util) {
         const item = args.ITEM;
         const list = util.target.lookupOrCreateList(args.LIST);
-        const index = Cast.toListIndex(args.INDEX, list.contents.length);
+        const index = Cast.toListIndex(args.INDEX, list.value.length);
         if (index === Cast.LIST_INVALID) {
             return;
         }
-        list.contents.splice(index - 1, 1, item);
+        list.value.splice(index - 1, 1, item);
     }
 
     getItemOfList (args, util) {
         const list = util.target.lookupOrCreateList(args.LIST);
-        const index = Cast.toListIndex(args.INDEX, list.contents.length);
+        const index = Cast.toListIndex(args.INDEX, list.value.length);
         if (index === Cast.LIST_INVALID) {
             return '';
         }
-        return list.contents[index - 1];
+        return list.value[index - 1];
     }
 
     lengthOfList (args, util) {
         const list = util.target.lookupOrCreateList(args.LIST);
-        return list.contents.length;
+        return list.value.length;
     }
 
     listContainsItem (args, util) {
         const item = args.ITEM;
         const list = util.target.lookupOrCreateList(args.LIST);
-        if (list.contents.indexOf(item) >= 0) {
+        if (list.value.indexOf(item) >= 0) {
             return true;
         }
         // Try using Scratch comparison operator on each item.
         // (Scratch considers the string '123' equal to the number 123).
-        for (let i = 0; i < list.contents.length; i++) {
+        for (let i = 0; i < list.value.length; i++) {
-            if (Cast.compare(list.contents[i], item) === 0) {
+            if (Cast.compare(list.value[i], item) === 0) {
                 return true;
             }
         }

src/engine/blocks.js

@@ -260,7 +260,7 @@ class Blocks {
             // If not, create it on the stage.
             // TODO create global and local variables when UI provides a way.
             if (!optRuntime.getEditingTarget().lookupVariableById(e.varId)) {
-                stage.createVariable(e.varId, e.varName);
+                stage.createVariable(e.varId, e.varName, e.varType);
             }
             break;
         case 'var_rename':
@@ -310,7 +310,7 @@ class Blocks {
         case 'field':
             // Update block value
             if (!block.fields[args.name]) return;
-            if (args.name === 'VARIABLE') {
+            if (args.name === 'VARIABLE' || args.name === 'LIST') {
                 // Get variable name using the id in args.value.
                 const variable = optRuntime.getEditingTarget().lookupVariableById(args.value);
                 if (variable) {

src/engine/execute.js

@@ -138,7 +138,7 @@ const execute = function (sequencer, thread) {
     // Add all fields on this block to the argValues.
     for (const fieldName in fields) {
         if (!fields.hasOwnProperty(fieldName)) continue;
-        if (fieldName === 'VARIABLE') {
+        if (fieldName === 'VARIABLE' || fieldName === 'LIST') {
             argValues[fieldName] = fields[fieldName].id;
         } else {
             argValues[fieldName] = fields[fieldName].value;

src/engine/list.js

@@ -1,18 +0,0 @@
-/**
- * @fileoverview
- * Object representing a Scratch list.
- */
-
-/**
-  * @param {!string} name Name of the list.
-  * @param {Array} contents Contents of the list, as an array.
-  * @constructor
-  */
-class List {
-    constructor (name, contents) {
-        this.name = name;
-        this.contents = contents;
-    }
-}
-
-module.exports = List;

src/engine/target.js

@@ -2,7 +2,6 @@ const EventEmitter = require('events');
 
 const Blocks = require('./blocks');
 const Variable = require('../engine/variable');
-const List = require('../engine/list');
 const uid = require('../util/uid');
 const {Map} = require('immutable');
 
@@ -88,7 +87,7 @@ class Target extends EventEmitter {
         const variable = this.lookupVariableById(id);
         if (variable) return variable;
         // No variable with this name exists - create it locally.
-        const newVariable = new Variable(id, name, 0, false);
+        const newVariable = new Variable(id, name, "", false);
         this.variables[id] = newVariable;
         return newVariable;
     }
@@ -117,24 +116,16 @@ class Target extends EventEmitter {
     /**
     * Look up a list object for this target, and create it if one doesn't exist.
     * Search begins for local lists; then look for globals.
+    * @param {!string} id Id of the list.
     * @param {!string} name Name of the list.
     * @return {!List} List object.
      */
-    lookupOrCreateList (name) {
+    lookupOrCreateList (id, name) {
-        // If we have a local copy, return it.
+        const list = this.lookupVariableById(id);
-        if (this.lists.hasOwnProperty(name)) {
+        if (list) return list;
-            return this.lists[name];
+        // No variable with this name exists - create it locally.
-        }
+        const newList = new Variable(id, name, "list", false);
-        // If the stage has a global copy, return it.
+        this.variables[id] = newList;
-        if (this.runtime && !this.isStage) {
-            const stage = this.runtime.getTargetForStage();
-            if (stage.lists.hasOwnProperty(name)) {
-                return stage.lists[name];
-            }
-        }
-        // No list with this name exists - create it locally.
-        const newList = new List(name, []);
-        this.lists[name] = newList;
         return newList;
     }
 
@@ -143,11 +134,11 @@ class Target extends EventEmitter {
      * dictionary of variables.
      * @param {string} id Id of variable
      * @param {string} name Name of variable.
+     * @param {string} type Type of variable, one of string, number, list
      */
-    createVariable (id, name) {
+    createVariable (id, name, type) {
         if (!this.variables.hasOwnProperty(id)) {
-            const newVariable = new Variable(id, name, 0,
+            const newVariable = new Variable(id, name, type, false);
-                false);
             this.variables[id] = newVariable;
         }
     }

src/engine/variable.js

@@ -9,19 +9,27 @@ class Variable {
     /**
      * @param {string} id Id of the variable.
      * @param {string} name Name of the variable.
-     * @param {(string|number)} value Value of the variable.
+     * @param {(string|number)} type Type of the variable, one of "" or "list"
      * @param {boolean} isCloud Whether the variable is stored in the cloud.
      * @constructor
      */
-    constructor (id, name, value, isCloud) {
+    constructor (id, name, type, isCloud) {
         this.id = id || uid();
         this.name = name;
-        this.value = value;
+        this.type = type;
         this.isCloud = isCloud;
+        switch (this.type) {
+        case "":
+            this.value = 0;
+            break;
+        case "list":
+            this.value = [];
+            break;
+        }
     }
 
     toXML () {
-        return `<variable type="" id="${this.id}">${this.name}</variable>`;
+        return `<variable type="${this.type}" id="${this.id}">${this.name}</variable>`;
     }
 }
 

src/serialization/sb2.js

@@ -13,7 +13,6 @@ const log = require('../util/log');
 const uid = require('../util/uid');
 const specMap = require('./sb2_specmap');
 const Variable = require('../engine/variable');
-const List = require('../engine/list');
 
 const {loadCostume} = require('../import/load-costume.js');
 const {loadSound} = require('../import/load-sound.js');
@@ -235,9 +234,10 @@ const parseScratchObject = function (object, runtime, extensions, topLevel) {
             const newVariable = new Variable(
                 getVariableId(variable.name),
                 variable.name,
-                variable.value,
+                "",
                 variable.isPersistent
             );
+            newVariable.value = variable.value;
             target.variables[newVariable.id] = newVariable;
         }
     }
@@ -251,10 +251,14 @@ const parseScratchObject = function (object, runtime, extensions, topLevel) {
         for (let k = 0; k < object.lists.length; k++) {
             const list = object.lists[k];
             // @todo: monitor properties.
-            target.lists[list.listName] = new List(
+            const newVariable = new Variable(
+                getVariableId(list.listName),
                 list.listName,
-                list.contents
+                "list",
+                list.isPersistent
             );
+            newVariable.value = list.contents;
+            target.variables[newVariable.id] = newVariable;
         }
     }
     if (object.hasOwnProperty('scratchX')) {

src/serialization/sb2_specmap.js

@@ -1252,7 +1252,7 @@ const specMap = {
         ]
     },
     'contentsOfList:': {
-        opcode: 'data_list',
+        opcode: 'data_listcontents',
         argMap: [
             {
                 type: 'field',

src/serialization/sb3.js

@@ -8,7 +8,6 @@ const vmPackage = require('../../package.json');
 const Blocks = require('../engine/blocks');
 const Sprite = require('../sprites/sprite');
 const Variable = require('../engine/variable');
-const List = require('../engine/list');
 
 const {loadCostume} = require('../import/load-costume.js');
 const {loadSound} = require('../import/load-sound.js');
@@ -125,22 +124,13 @@ const parseScratchObject = function (object, runtime, extensions) {
             const newVariable = new Variable(
                 variable.id,
                 variable.name,
-                variable.value,
+                variable.type,
                 variable.isPersistent
             );
+            newVariable.value = variable.value;
             target.variables[newVariable.id] = newVariable;
         }
     }
-    if (object.hasOwnProperty('lists')) {
-        for (let k = 0; k < object.lists.length; k++) {
-            const list = object.lists[k];
-            // @todo: monitor properties.
-            target.lists[list.listName] = new List(
-                list.listName,
-                list.contents
-            );
-        }
-    }
     if (object.hasOwnProperty('x')) {
         target.x = object.x;
     }