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Sigil patrol: change fn@ fn& fn~ to @fn &fn ~fn

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This also involves removing references to the old long-form closure
syntax, which pcwalton alleges is deprecated and which was never updated
for the new forms, e.g. `@fn() {}` is illegal.
This commit is contained in:
Ben Striegel 2012-10-12 20:48:45 -04:00 committed by Tim Chevalier
parent e94e82cb8e
commit 5e1d0bab80
1 changed files with 11 additions and 25 deletions
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36
doc/tutorial.md
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@ -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.