diff --git a/doc/tutorial.md b/doc/tutorial.md index b411e1232b7..67c9bcd8281 100644 --- a/doc/tutorial.md +++ b/doc/tutorial.md @@ -1569,7 +1569,7 @@ let bloop = |well, oh: mygoodness| -> what_the { fail oh(well) }; ~~~~ There are several forms of closure, each with its own role. The most -common, called a _stack closure_, has type `fn&` and can directly +common, called a _stack closure_, has type `&fn` and can directly access local variables in the enclosing scope. ~~~~ @@ -1591,7 +1591,7 @@ pervasively in Rust code. When you need to store a closure in a data structure, a stack closure will not do, since the compiler will refuse to let you store it. For this purpose, Rust provides a type of closure that has an arbitrary -lifetime, written `fn@` (boxed closure, analogous to the `@` pointer +lifetime, written `@fn` (boxed closure, analogous to the `@` pointer type described earlier). This type of closure *is* first-class. A managed closure does not directly access its environment, but merely @@ -1604,8 +1604,9 @@ returns it from a function, and then calls it: ~~~~ # extern mod std; -fn mk_appender(suffix: ~str) -> fn@(~str) -> ~str { - return fn@(s: ~str) -> ~str { s + suffix }; +fn mk_appender(suffix: ~str) -> @fn(~str) -> ~str { + // The compiler knows that we intend this closure to be of type @fn + return |s| s + suffix; } fn main() { @@ -1614,22 +1615,9 @@ fn main() { } ~~~~ -This example uses the long closure syntax, `fn@(s: ~str) ...`. Using -this syntax makes it explicit that we are declaring a boxed -closure. In practice, boxed closures are usually defined with the -short closure syntax introduced earlier, in which case the compiler -infers the type of closure. Thus our managed closure example could -also be written: - -~~~~ -fn mk_appender(suffix: ~str) -> fn@(~str) -> ~str { - return |s| s + suffix; -} -~~~~ - ## Owned closures -Owned closures, written `fn~` in analogy to the `~` pointer type, +Owned closures, written `~fn` in analogy to the `~` pointer type, hold on to things that can safely be sent between processes. They copy the values they close over, much like managed closures, but they also own them: that is, no other code can access @@ -1649,12 +1637,10 @@ callers may pass any kind of closure. ~~~~ fn call_twice(f: fn()) { f(); f(); } -call_twice(|| { "I am an inferred stack closure"; } ); -call_twice(fn&() { "I am also a stack closure"; } ); -call_twice(fn@() { "I am a managed closure"; }); -call_twice(fn~() { "I am an owned closure"; }); -fn bare_function() { "I am a plain function"; } -call_twice(bare_function); +let closure = || { "I'm a closure, and it doesn't matter what type I am"; }; +fn function() { "I'm a normal function"; } +call_twice(closure); +call_twice(function); ~~~~ > ***Note:*** Both the syntax and the semantics will be changing @@ -1715,7 +1701,7 @@ parentheses, where it looks more like a typical block of code. `do` is a convenient way to create tasks with the `task::spawn` -function. `spawn` has the signature `spawn(fn: fn~())`. In other +function. `spawn` has the signature `spawn(fn: ~fn())`. In other words, it is a function that takes an owned closure that takes no arguments.