swift 中的空格规则是什么

Question

我在 swift 的操场上练习，但我不明白为什么 swift 对程序员应该在何处提供空格而在何处不提供过于具体。我在很多网站和聊天室问过这个问题，但没有得到任何答案。

var j: Int = 34 // Right
var j:Int=23 //Wrong

还有，在class

self.variable-= 5 //Wrong. Error: Consecutive statements must be followed by ;
self.variable-=5 // Right
self.variable -= 5 // Right

;

即使是这个“:”有时也会产生一些空格问题。

我认为空格对代码绝对没有影响。它通常只是为了程序员的利益。它只是使代码更具可读性。阅读有关空格的所有 swift 规则的最佳资源是什么。

Answer 1

可以在此处找到问题第二部分的答案swift docs

The whitespace around an operator is used to determine whether an operator is used as a prefix operator, a postfix operator, or a binary operator. This behavior is summarized in the following rules:

If an operator has whitespace around both sides or around neither side, it is treated as a binary operator. As an example, the + operator in a+b and a + b is treated as a binary operator.

If an operator has whitespace on the left side only, it is treated as a prefix unary operator. As an example, the ++ operator in a ++b is treated as a prefix unary operator.

If an operator has whitespace on the right side only, it is treated as a postfix unary operator. As an example, the ++ operator in a++ b is treated as a postfix unary operator.

If an operator has no whitespace on the left but is followed immediately by a dot (.), it is treated as a postfix unary operator. As an example, the ++ operator in a++.b is treated as a postfix unary operator (a++ .b rather than a ++ .b).

etc... (read the docs for more on this)

至于你问题的第一部分，我没有发现任何一种声明变量的方式有任何问题。

var j: Int = 34
var j:Int=23

所提供代码的唯一问题是您在同一范围内声明了 j 两次。尝试将其中一个 j 更改为 x 或 y 或其他内容。

如果您想知道

var j:Int =10

或

var j:Int= 10

看看上面的规则。 = 是一个运算符，因此如果您要执行其中任何一个操作，它将被视为前缀或后缀，并且您会收到 prefix/postfix = is reserved

的错误

由于存在一元加号和一元减号运算符等运算符，这些规则很重要。编译器需要能够区分二进制加号和一元加号运算符。 List of operators

swift 中的空格规则是什么

what are the rules for spaces in swift

swift

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