是否可以将Closure / Function作为结构的成员？(Is it possible to have a Closure/Function as a member of a struct?)

是否可以将Closure / Function作为结构的成员？(Is it possible to have a Closure/Function as a member of a struct?) struct Foo<A,B>{ f: |A| -> B // err: Missing life time specifier } impl<A,B> Foo<A,B>{ fn new(f: |A| -> B) -> Foo<A,B>{ Foo {f:f} } }

为什么我会收到此错误？ 我也希望Foo能够处理正常的函数和闭包。

我知道过去有一个关闭改革，那么f的正确签名是什么，以便Foo能够使用闭包和函数？

struct Foo<A,B>{ f: |A| -> B // err: Missing life time specifier } impl<A,B> Foo<A,B>{ fn new(f: |A| -> B) -> Foo<A,B>{ Foo {f:f} } }

Why do I get this error? I also want Foo to work with normal functions and closures.

I know that there was a closure reform in the past, so what would be the correct signature for f so that Foo works with closures and functions?

最满意答案

如果在结构中放置闭包，则需要明确命名生命周期。

struct Foo<'a,A,B>{ f: |A|:'a -> B } impl<'a,A,B> Foo<'a,A,B>{ fn new(f: |A| -> B) -> Foo<A,B>{ Foo {f:f} } }

有关这方面的更多信息，您可以阅读此博客文章 ，其中包含此案例。 以下是博客文章中的相关部分：

将指定边界的两种情况是（1）将闭包放入结构中，其中必须明确命名所有生命周期，以及（2）指定数据并行API。 在第一种情况下，一个包含闭包的结构定义，你希望写下面的东西...

If you place a closure inside of a struct you need to explicitly name the lifetime.

struct Foo<'a,A,B>{ f: |A|:'a -> B } impl<'a,A,B> Foo<'a,A,B>{ fn new(f: |A| -> B) -> Foo<A,B>{ Foo {f:f} } }

For more information on that you can read this blog post which coveres this case. Here is the relevant part from the blog post:

The two cases where bounds would be specified are (1) placing closures into a struct, where all lifetimes must be explicitly named and (2) specifying data-parallel APIs. In the first case, a struct definition that contains a closure, you would expect to write something like the following ...