字符串插值在Kotlin中如何工作? [英] How does string interpolation work in Kotlin?

问题描述

Kotlin编译器是否使用类似的方式翻译"Hello, $name!"

Does the Kotlin compiler translate "Hello, $name!" using something like

java.lang.String.format("Hello, %s!", name)

还是还有其他机制?

例如，如果我有一个像这样的课程:

And if I have a class like this for example:

class Client {
  val firstName: String
  val lastName: String
  val fullName: String
    get() = "$firstName $lastName"
}

此getter会返回缓存的字符串还是会尝试构建新的字符串?我应该改用lazyOf委托吗?

Will this getter return a cached string or will it try to build a new string? Should I use lazyOf delegate instead?

我知道除非有成千上万的fullName调用，否则不会有性能问题，但是除了如何使用它之外，我还没有找到有关此功能的文档.

I know that there will be no performance issue unless there will be millions of calls to fullName, but I haven't found documentation about this feature except for how to use it.

推荐答案

Kotlin编译器将此代码转换为:

The Kotlin compiler translates this code to:

new StringBuilder().append("Hello, ").append(name).append("!").toString()

不执行缓存:每次评估包含字符串模板的表达式时，都会再次构建结果字符串.

There is no caching performed: every time you evaluate an expression containing a string template, the resulting string will be built again.

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