Smalltalk 语言 对象克隆案例 复杂对象深拷贝

小谈Smalltalk^【1】语言中的对象克隆^【2】：复杂对象^【3】的深拷贝^【4】实现

在面向对象编程中，对象克隆是一个常见且重要的操作。它允许我们创建对象的副本，而不影响原始对象的状态。在Smalltalk语言中，对象克隆尤为重要，因为它直接支持深拷贝和浅拷贝^【5】的概念。本文将围绕Smalltalk语言的对象克隆，特别是复杂对象的深拷贝，展开讨论。

Smalltalk语言简介

Smalltalk是一种面向对象的编程语言，由Alan Kay等人于1970年代初期设计。它以其简洁的语法、动态类型和强大的元编程^【6】能力而闻名。在Smalltalk中，一切皆对象，包括数字、字符串、类和对象本身。

对象克隆的概念

在Smalltalk中，对象克隆可以分为两种类型：浅拷贝和深拷贝。

- 浅拷贝：创建一个新对象，并将原始对象的所有可访问属性复制到新对象中。如果属性是基本数据类型，则直接复制值；如果属性是对象，则复制引用，而不是对象本身。
- 深拷贝：创建一个新对象，并将原始对象的所有属性复制到新对象中。如果属性是基本数据类型，则直接复制值；如果属性是对象，则创建该对象的副本。

深拷贝的实现

下面是一个Smalltalk语言中实现深拷贝的示例代码。我们将以一个复杂对象为例，该对象包含其他对象作为属性。

```smalltalk
| objectToClone<sup>【7】</sup> |
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