Add Chapter 3

src/createContext.ts

@@ -125,23 +125,22 @@ export const importBuiltins = (context: Context, externalBuiltIns: CustomBuiltIn
     defineSymbol(context, 'equal', list.equal)
   }
 
+  if (context.chapter >= 3) {
+    defineSymbol(context, 'set_head', list.set_head)
+    defineSymbol(context, 'set_tail', list.set_tail)
+    defineSymbol(context, 'array_length', misc.array_length)
+  }
+
   if (context.chapter >= Infinity) {
     // previously week 4
     defineSymbol(context, 'alert', alert)
-    defineSymbol(context, 'math_floor', Math.floor)
     // tslint:disable-next-line:ban-types
     defineSymbol(context, 'timed', (f: Function) => misc.timed(context, f, context.externalContext, externalBuiltIns.display))
     // previously week 5
     defineSymbol(context, 'assoc', list.assoc)
     defineSymbol(context, 'draw', visualiseList)
     // previously week 6
     defineSymbol(context, 'is_number', misc.is_number)
-    // previously week 8
-    defineSymbol(context, 'undefined', undefined)
-    defineSymbol(context, 'set_head', list.set_head)
-    defineSymbol(context, 'set_tail', list.set_tail)
-    // previously week 9
-    defineSymbol(context, 'array_length', misc.array_length)
   }
 }
 

src/rules/noDeclareMutable.ts

@@ -27,6 +27,7 @@ export class NoDeclareMutableError implements SourceError {
 
 const noDeclareMutable: Rule<es.VariableDeclaration> = {
   name: 'no-declare-mutable',
+  disableOn: 3,
 
   checkers: {
     VariableDeclaration(node: es.VariableDeclaration) {

src/rules/noImplicitDeclareUndefined.ts

@@ -22,7 +22,7 @@ export class NoImplicitDeclareUndefinedError implements SourceError {
       A variable declaration assigns a value to a name.
       For instance, to assign 20 to ${this.node.name}, you can write:
 
-        var ${this.node.name} = 20;
+        let ${this.node.name} = 20;
 
         ${this.node.name} + ${this.node.name}; // 40
     `

src/rules/noNonEmptyList.ts

@@ -24,7 +24,7 @@ export class NoNonEmptyListError implements SourceError {
 const noNonEmptyList: Rule<es.ArrayExpression> = {
   name: 'no-non-empty-list',
 
-  disableOn: 9,
+  disableOn: 3,
 
   checkers: {
     ArrayExpression(node: es.ArrayExpression) {

src/syntaxTypes.ts

@@ -19,21 +19,21 @@ const syntaxTypes: { [nodeName: string]: number } = {
   // Chapter 2
   ArrayExpression: 2,
 
+  // Chapter 3
+  AssignmentExpression: 3,
+  ForStatement: 3,
+  WhileStatement: 3,
+  BreakStatement: 3,
+  ContinueStatement: 3,
+  ThisExpression: 3,
+  ObjectExpression: 3,
+  MemberExpression: 3,
+  Property: 3,
+  UpdateExpression: 3,
+
   // Week 5
   EmptyStatement: 5,
-  // preivously Week 8
-  AssignmentExpression: 8,
-  WhileStatement: 8,
-  // previously Week 9
-  ForStatement: 9,
-  BreakStatement: 9,
-  ContinueStatement: 9,
-  MemberExpression: 9,
   // previously Week 10
-  ThisExpression: 10,
-  ObjectExpression: 10,
-  Property: 10,
-  UpdateExpression: 10,
   NewExpression: 10,
   // Disallowed Forever
   SwitchStatement: Infinity,