---

yaml
---
r: 29932
b: refs/heads/incoming
c: 08441fc
h: refs/heads/master
v: v3

Author: graydon

[refs]

@@ -6,7 +6,7 @@ refs/heads/try: d324a424d8f84b1eb049b12cf34182bda91b0024
 refs/tags/release-0.1: 1f5c5126e96c79d22cb7862f75304136e204f105
 refs/heads/ndm: f3868061cd7988080c30d6d5bf352a5a5fe2460b
 refs/heads/try2: d0c6ce338884ee21843f4b40bf6bf18d222ce5df
-refs/heads/incoming: 076dab92f73bb882e59e2f6a1ee6ba2b47bf6110
+refs/heads/incoming: 08441fca76084b97c21ead917e54ce6c66d5d012
 refs/heads/dist-snap: 2f32a1581f522e524009138b33b1c7049ced668d
 refs/tags/release-0.2: c870d2dffb391e14efb05aa27898f1f6333a9596
 refs/tags/release-0.3: b5f0d0f648d9a6153664837026ba1be43d3e2503

branches/incoming/AUTHORS.txt

@@ -49,6 +49,7 @@ Jeff Muizelaar <[email protected]>
 Jeff Olson <[email protected]>
 Jeffrey Yasskin <[email protected]>
 Jesse Ruderman <[email protected]>
+Jim Blandy <[email protected]>
 Joe Pletcher <[email protected]>
 Jon Morton <[email protected]>
 Jonathan Sternberg <[email protected]>

branches/incoming/doc/rust.md

@@ -211,7 +211,7 @@ The keywords in [source files](#source-files) are the following strings:
 ~~~~~~~~ {.keyword}
 again assert
 break
-check class const copy
+check const copy
 drop
 else enum export extern
 fail false fn for
@@ -220,6 +220,7 @@ let log loop
 match mod mut
 pure
 return
+struct
 true trait type
 unchecked unsafe
 while
@@ -1097,151 +1098,6 @@ enum list<T> {
 let a: list<int> = cons(7, @cons(13, @nil));
 ~~~~
 
-### Classes
-
-A _class_ is a named record type that collects together fields and
-methods. It must have a _constructor_ (a function called `new` that
-returns a new instance of the class), and may have a destructor (a
-nullary function called `drop` that executes before the memory manager
-frees the memory for a given class). For historical reasons, we may
-call a class with a destructor and a single field a "resource".
-
-A _class item_ declares a class type:
-
-~~~~
-class file_descriptor {
-    let fd: libc::c_int;
-    new(fd: libc::c_int) { self.fd = fd; }
-    drop { libc::close(self.fd); }
-}
-~~~~
-
-Calling the `file_descriptor` constructor function on an integer will
-produce a value with the `file_descriptor` type.
-
-_Fields_ are immutable by default, so instances of `file_descriptor`
-can't have their `fd` fields reassigned. A mutable field declaration
-looks like:
-
-~~~~
-    let mut fd: libc::c_int;
-~~~~
-
-The only exception is that the body of the class constructor begins
-with all the class's fields uninitialized, and is allowed to -- in
-fact, must -- initialize all the fields. The compiler enforces this
-invariant.
-
-Usually, the class constructor stores its argument or arguments in the
-class's named fields. In this case, the `file_descriptor`'s data field
-would be accessed like `f.fd`, if `f` is a value of type
-`file_descriptor`. By default, class fields are _public_: they can be
-accessed both from methods inside the class, and code outside the
-class. Classes can also have private fields:
-
-~~~~
-class file_descriptor {
-    let fd: *libc::FILE;
-    new(fd: *libc::FILE) {
-      self.fd = fd; self.name = none;
-    }
-    priv {
-      let mut name: option<~str>;
-    }
-    fn get_name() -> ~str {
-      match self.name {
-         none    => fail ~"File has no name!",
-         some(n) => n
-      }
-    }
-}
-~~~~
-
-Private fields are instance-private: methods in a class `C` can access
-`self`'s private fields, but not private fields of other values of
-type `C`. Code outside a class can't access any private fields.
-
-A class item may contain _methods_, which take an implicit `self`
-argument:
-
-~~~~
-class file_descriptor {
-    let fd: *libc::FILE;
-    new(fd: *libc::FILE) { self.fd = fd; }
-    fn flush() {
-       libc::fflush(self.fd);
-    }
-}
-~~~~
-
-In this case, ```open``` is a nullary method that calls the
-```fopen``` function, defined in another library, on the ```fd```
-field. As in this example, methods must refer to their self's fields
-as fields of ```self```; bare references to ```fd``` can't
-occur. Methods can be public or private; just like fields, they are
-public by default and private if enclosed in a `priv` section.
-
-Classes may be polymorphic:
-
-~~~~
-class file<A: copy> {
-  let data: A;
-  let fd: *libc::FILE;
-  new(data: A, fd: *libc::FILE) { self.data = data; self.fd = fd; }
-}
-~~~~
-
-Methods may also be polymorphic, and can have additional type
-parameters other than those bound in the class:
-
-~~~~
-class file<A: copy> {
-  let data: A;
-  let fd: *libc::FILE;
-  new(fd: *libc::FILE, data: A) { self.fd = fd; self.data = data; }
-  fn map_data<B>(f: fn(A) -> B) -> B {
-     f(self.data)
-  }
-}
-~~~~
-
-Classes do not support inheritance, except through traits. As a
-result, all class method dispatch is static (non-virtual).
-
-A class may implement a trait (see [traits](#traits)):
-
-~~~~
-trait to_str {
-  fn to_str() -> ~str;
-}
-
-class file : to_str {
-  let fd: *libc::FILE;
-  new(fd: *libc::FILE) { self.fd = fd; }
-  fn to_str() -> ~str { ~"a file" }
-}
-~~~~
-
-The syntax `class file: to_str` is pronounced "class `file`
-implements trait `to_str`".
-
-Class instances may be allocated on the stack, in the exchange heap,
-or on the task heap. A value with a class type ```C``` has a
-noncopyable [type kind](#type-kinds) if ```C``` has a destructor, and
-thus may not be copied. Class types that don't have destructors may be
-copied if all their fields are copyable.
-
-The semantics guarantee that for each constructed resource value, the
-destructor will run once: when the value is disposed of (barring
-drastic program termination that somehow prevents unwinding from
-taking place). For stack-allocated values, disposal happens when the
-value goes out of scope. For values in shared boxes, it happens when
-the reference count of the box reaches zero.
-
-The order of fields in a class instance is significant; its runtime
-representation is the same as that of a record with identical fields
-laid out in the same order.
-
 ### Traits
 
 A _trait item_ describes a set of method types. [_implementation
@@ -1348,7 +1204,7 @@ trait.  The methods in such an implementation can only be used
 statically (as direct calls on the values of the type that the
 implementation targets). In such an implementation, the `of` clause is
 not given, and the name is mandatory.  Such implementations are
-limited to nominal types (enums, classes) and the implementation must
+limited to nominal types (enums, structs) and the implementation must
 appear in the same module or a sub-module as the receiver type.
 
 _When_ a trait is specified, all methods declared as part of the
@@ -2744,9 +2600,9 @@ fn main() {
 In this example, the trait `printable` occurs as a type in both the type signature of
 `print`, and the cast expression in `main`.
 
-### Class types
+### Struct types
 
-Every class item defines a type. See [classes](#classes).
+Every struct item defines a type.
 
 ### Type parameters
 
@@ -2766,7 +2622,7 @@ type `~[B]`, a vector type with element type `B`.
 
 ### Self type
 
-The special type `self` has a meaning within methods inside a class or
+The special type `self` has a meaning within methods inside an
 impl item. It refers to the type of the implicit `self` argument. For
 example, in:
 
@@ -2781,19 +2637,7 @@ impl ~str: printable {
 ~~~~~~
 
 `self` refers to the value of type `str` that is the receiver for a
-call to the method `to_str`. Similarly, in a class declaration:
-
-~~~~~~
-class cat {
-  let mut meows: uint;
-  new() { self.meows = 0; }
-  fn meow() { self.meows = self.meows + 1; }
-}
-~~~~~~
-
-`self` refers to the class instance that is the receiver of the method
-(except in the constructor `new`, where `self` is the class instance
-that the constructor implicitly returns).
+call to the method `to_str`.
 
 ## Type kinds
 

branches/incoming/doc/tutorial.md

@@ -1560,7 +1560,7 @@ if favorite_crayon_name.len() > 5 {
 
 Named functions, like those we've seen so far, may not refer to local
 variables declared outside the function - they do not "close over
-their environment". For example you couldn't write the following:
+their environment". For example, you couldn't write the following:
 
 ~~~~ {.ignore}
 let foo = 10;
@@ -1821,85 +1821,6 @@ fn contains(v: ~[int], elt: int) -> bool {
 
 `for` syntax only works with stack closures.
 
-# Classes
-
-Rust lets users define new types with fields and methods, called 'classes', in
-the style of object-oriented languages.
-
-> ***Warning:*** Rust's classes are in the process of changing rapidly. Some more
-> information about some of the potential changes is [here][classchanges].
-
-[classchanges]: http://pcwalton.github.com/blog/2012/06/03/maximally-minimal-classes-for-rust/
-
-An example of a class:
-
-~~~~
-class example {
-  let mut x: int;
-  let y: int;
-
-  priv {
-    let mut private_member: int;
-    fn private_method() {}
-  }
-
-  new(x: int) {
-    // Constructor
-    self.x = x;
-    self.y = 7;
-    self.private_member = 8;
-  }
-
-  fn a() {
-    io::println(~"a");
-  }
-
-  drop {
-    // Destructor
-    self.x = 0;
-  }
-}
-
-fn main() {
-  let x: example = example(1);
-  let y: @example = @example(2);
-  x.a();
-  x.x = 5;
-}
-~~~~
-
-Fields and methods are declared just like functions and local variables, using
-'fn' and 'let'. As usual, 'let mut' can be used to create mutable fields. At
-minimum, Rust classes must have at least one field.
-
-Rust classes must also have a constructor, and can optionally have a destructor
-as well. The constructor and destructor are declared as shown in the example:
-like methods named 'new' and 'drop', but without 'fn', and without arguments
-for drop.
-
-In the constructor, the compiler will enforce that all fields are initialized
-before doing anything that might allow them to be accessed. This includes
-returning from the constructor, calling any method on 'self', calling any
-function with 'self' as an argument, or taking a reference to 'self'. Mutation
-of immutable fields is possible only in the constructor, and only before doing
-any of these things; afterwards it is an error.
-
-Private fields and methods are declared as shown above, using a `priv { ... }`
-block within the class. They are accessible only from within the same instance
-of the same class. (For example, even from within class A, you cannot call
-private methods, or access private fields, on other instances of class A; only
-on `self`.) This accessibility restriction may change in the future.
-
-As mentioned below, in the section on copying types, classes with destructors
-are considered 'resource' types and are not copyable.
-
-Declaring a class also declares its constructor as a function of the same name.
-You can construct an instance of the class, as in the example, by calling that
-function. The function and the type, though they have the same name, are
-otherwise independent. As with other Rust types, you can use `@` or `~` to
-construct a heap-allocated instance of a class, either shared or unique; just
-call e.g. `@example(...)` as shown above.
-
 # Argument passing
 
 Rust datatypes are not trivial to copy (the way, for example,
@@ -1938,6 +1859,13 @@ match my_rec {
 }
 ~~~~
 
+It's unsafe to dereference `b` in the second `log` expression, because `b` is
+a _pointer_ to the inside of `my_rec`, and the assignment statement has
+allocated a new record and assigned `my_rec` to point to it. Thus, the old
+contents of `my_rec` are no longer live, and `b` is dangling at this point.
+The borrow-checking analysis inside the compiler recognizes this situation
+and rejects the program.
+
 ## Argument passing styles
 
 The fact that arguments are conceptually passed by safe reference does