swift - Swift 中改变函数的命名约定

Question

在 Ruby 中，变异方法(即修改 self 的方法)按照惯例用感叹号 (!) 标记，以将它们与不修改 self 的类似命名方法分开。

例如 Array#sort 返回一个排序的数组，但是 Array#sort! 修改调用它的数组。

我现在开始研究 Swift。我如何命名变异方法以将其与其非变异孪生方法分开？

我知道 Python 有 sorted(list) 和 list.sort()。这是一个值得遵循的好模式吗，即 .sorted()(非变异)和 .sort()(变异)？

那些不容易以这种方式转换的名称怎么样，例如 String#next 与 String#next!？

Answer 1

关于发布官方指南，这里是: https://swift.org/documentation/api-design-guidelines/#name-according-to-side-effects

Name Mutating/nonmutating method pairs consistently. A mutating method will often have a nonmutating variant with similar semantics, but that returns a new value rather than updating an instance in-place.

• When the operation is naturally described by a verb, use the verb’s imperative for the mutating method and apply the “ed” or “ing” suffix to name its nonmutating counterpart.

  Mutating    Nonmutating
  x.sort()    z = x.sorted()
  x.append(y) z = x.appending(y)
  

  Prefer to name the nonmutating variant using the verb’s past participle (usually appending “ed”):

  /// Reverses `self` in-place.
  mutating func reverse()
  
  /// Returns a reversed copy of `self`.
  func reversed() -> Self
  ...
  x.reverse()
  let y = x.reversed()
  

  When adding “ed” is not grammatical because the verb has a direct object, name the nonmutating variant using the verb’s present participle, by appending “ing.”

  /// Strips all the newlines from `self`
  mutating func stripNewlines()
  
  /// Returns a copy of `self` with all the newlines stripped.
  func strippingNewlines() -> String
  ...
  s.stripNewlines()
  let oneLine = t.strippingNewlines()
  

• When the operation is naturally described by a noun, use the noun for the nonmutating method and apply the “form” prefix to name its mutating counterpart.

  Nonmutating         Mutating
  x = y.union(z)      y.formUnion(z)
  j = c.successor(i)  c.formSuccessor(&i)
  

Ray Wenderlich自己总结一下 Swift Style Guide :

verb methods follow the -ed, -ing rule for the non-mutating version
noun methods follow the formX rule for the non-mutating version

请注意，由于提案:SE-0059 by Dave Abrahams，官方指南已针对 Swift 3 进行了更新。 , Update API Naming Guidelines and Rewrite Set APIs Accordingly , 2016 年 4 月 18 日批准后。

但五天前，即 2016 年 4 月 13 日，Erica Sadun在她的文章中表达了一些不同的观点Stop the Madness and fix the Swift API guidelines .让我们补充一下，Erica 之前就此事写过她自己的文章，Naming Methods and Functions ，也可以在她的书 Swift Style 中找到。为了好玩，她试图explain mutating naming with emoji .