在
Swift中,据我所知,闭包保留了他们的环境,而普通的功能却没有.
考虑下面的f(返回一个函数)和h(返回一个闭包). f()()和h()()都返回3.为什么f()()不会导致运行时错误？
func f() -> () -> Int {
let a = 3
func g() -> Int {
return a
}
return g
}
func h() -> () -> Int {
let a = 3
return { () in a }
}
解决方法
你所写的并不完全正确,因为根据
documentation：
Global functions are closures that have a name and do not capture any values.
Nested functions are closures that have a name and can capture values from their enclosing function.
Closure expressions are unnamed closures written in a lightweight Syntax that can capture values from their surrounding context.
所以g()会捕获值.
