闭包
闭包*在Rust 是一个稍微专业的语法，可以捕捉到封闭的环境函数。%uA0这种语法和能力使它们在运行使用非常方便。一些特性包括：
-
使用%uA0
||%uA0替代%uA0()%uA0围绕输入变量。 - 输入和返回类型可以推断出。
- 输入变量名称必须指定。
-
主体定界 (
{}) 是可选的一个表达式。强制性其他。 - 外环境变量可能被捕获。
-
调用闭包和函数与%uA0
call(var)是完全一样的
fn main() {
// Increment via closures and functions.
fn function (i: i32) -> i32 { i + 1 }
// Annotation is identical to function annotation but is optional
// as are the `{}` wrapping the body. These nameless functions
// are assigned to appropriately named variables.
let closure_annotated = |i: i32| -> i32 { i + 1 }
let closure_inferred = |i | i + 1
let i = 1
// Call the function and closures.
println!("function: {}", function(i))
println!("annotated closure: {}", closure_annotated(i))
println!("inferred closure: {}", closure_inferred(i))
// A closure taking no arguments which returns an `i32`.
// The return type is inferred.
let one = || 1
println!("closure returning one: {}", one())
// It is possible to capture variables from the enclosing
// environment something which is impossible with functions.
let professor_x = "Charles Xavier"
// A closure which takes no argument, returning nothing, prints
// a variable from the enclosing scope.
let print = || println!("Professor X&aposs name is: {}", professor_x)
// Call the closure.
print()
}
*.也被称为lambda表达式或匿名函数。