@ -519,4 +519,4 @@ case let (x, y):
|
||||
|
||||
这三个*case*都声明了常量`x`和`y`的占位符,用于临时获取元组`yetAnotherPoint`的两个值。这些常量被用作`where`语句的一部分,从而创建一个动态的过滤器(filter)。当且仅当`where`语句的条件为`真`时,匹配到的*case*块才会被执行。
|
||||
|
||||
就像是值绑定中的例子,由于最后一个*case*块匹配了余下所有可能的值,`switch`语句就已经完备了,因此不需要再书写默认块。
|
||||
就像是值绑定中的例子,由于最后一个*case*块匹配了余下所有可能的值,`switch`语句就已经完备了,因此不需要再书写默认块。
|
||||
@ -67,7 +67,7 @@ for `initialzation`; `condition`; `increment` {
|
||||
|
||||
> *for-statement* → **for** [*for-init*](https://developer.apple.com/library/prerelease/ios/documentation/Swift/Conceptual/Swift_Programming_Language/Statements.html#//apple_ref/swift/grammar/for-init) *opt* **;** [*expression*](https://developer.apple.com/library/prerelease/ios/documentation/Swift/Conceptual/Swift_Programming_Language/Expressions.html#//apple_ref/swift/grammar/expression) *opt* **;** [*expression*](https://developer.apple.com/library/prerelease/ios/documentation/Swift/Conceptual/Swift_Programming_Language/Expressions.html#//apple_ref/swift/grammar/expression) *opt* [*code-block*](https://developer.apple.com/library/prerelease/ios/documentation/Swift/Conceptual/Swift_Programming_Language/Declarations.html#//apple_ref/swift/grammar/code-block)
|
||||
|
||||
> *for-statement* → **for ( ** [*for-init*](https://developer.apple.com/library/prerelease/ios/documentation/Swift/Conceptual/Swift_Programming_Language/Statements.html#//apple_ref/swift/grammar/for-init) *opt* **;** [*expression*](https://developer.apple.com/library/prerelease/ios/documentation/Swift/Conceptual/Swift_Programming_Language/Expressions.html#//apple_ref/swift/grammar/expression) *opt* **;** [*expression*](https://developer.apple.com/library/prerelease/ios/documentation/Swift/Conceptual/Swift_Programming_Language/Expressions.html#//apple_ref/swift/grammar/expression) *opt* **)** [*code-block*](https://developer.apple.com/library/prerelease/ios/documentation/Swift/Conceptual/Swift_Programming_Language/Declarations.html#//apple_ref/swift/grammar/code-block)
|
||||
> *for-statement* → **for (** [*for-init*](https://developer.apple.com/library/prerelease/ios/documentation/Swift/Conceptual/Swift_Programming_Language/Statements.html#//apple_ref/swift/grammar/for-init) *opt* **;** [*expression*](https://developer.apple.com/library/prerelease/ios/documentation/Swift/Conceptual/Swift_Programming_Language/Expressions.html#//apple_ref/swift/grammar/expression) *opt* **;** [*expression*](https://developer.apple.com/library/prerelease/ios/documentation/Swift/Conceptual/Swift_Programming_Language/Expressions.html#//apple_ref/swift/grammar/expression) *opt* **)** [*code-block*](https://developer.apple.com/library/prerelease/ios/documentation/Swift/Conceptual/Swift_Programming_Language/Declarations.html#//apple_ref/swift/grammar/code-block)
|
||||
|
||||
> *for-statement* → [*variable-declaration*](https://developer.apple.com/library/prerelease/ios/documentation/Swift/Conceptual/Swift_Programming_Language/Declarations.html#//apple_ref/swift/grammar/variable-declaration) | [*expression-list*](https://developer.apple.com/library/prerelease/ios/documentation/Swift/Conceptual/Swift_Programming_Language/Expressions.html#//apple_ref/swift/grammar/expression-list)
|
||||
|
||||
@ -366,7 +366,7 @@ continue `label name`
|
||||
|
||||
```swift
|
||||
return
|
||||
return `表达式`
|
||||
return `expression`
|
||||
```
|
||||
|
||||
当`return`语句后面带表达式时,表达式的值将会返回给调用者。如果表达式值的类型与调用者期望的类型不匹配,Swift 则会在返回表达式的值之前将表达式值的类型转换为调用者期望的类型。
|
||||
|
||||
Reference in New Issue
Block a user