Add local functions and closures

src/com/craftinginterpreters/lox/Interpreter.java

@@ -153,7 +153,7 @@ class Interpreter implements Expr.Visitor<Object>, Stmt.Visitor<Void> {
 
     @Override
     public Void visitFunctionStmt(Stmt.Function stmt) {
-        LoxFunction function = new LoxFunction(stmt);
+        LoxFunction function = new LoxFunction(stmt, environment);
         environment.define(stmt.name.lexeme, function);
         return null;
     }

src/com/craftinginterpreters/lox/LoxFunction.java

@@ -4,8 +4,10 @@ import java.util.List;
 
 class LoxFunction implements LoxCallable {
     private final Stmt.Function declaration;
+    private final Environment closure;
 
-    LoxFunction(Stmt.Function declaration) {
+    LoxFunction(Stmt.Function declaration, Environment closure) {
+        this.closure = closure;
         this.declaration = declaration;
     }
 
@@ -16,7 +18,7 @@ class LoxFunction implements LoxCallable {
 
     @Override
     public Object call(Interpreter interpreter, List<Object> arguments) {
-        Environment environment = new Environment(interpreter.globals);
+        Environment environment = new Environment(closure);
 
         for (int i = 0; i < declaration.params.size(); i++) {
             environment.define(declaration.params.get(i).lexeme, arguments.get(i));