---

yaml
---
r: 140421
b: refs/heads/try2
c: 4a4646f
h: refs/heads/master
i:
  140419: aa8a5fb
v: v3

Author: brson

[refs]

@@ -5,7 +5,7 @@ refs/heads/snap-stage3: 78a7676898d9f80ab540c6df5d4c9ce35bb50463
 refs/heads/try: 519addf6277dbafccbb4159db4b710c37eaa2ec5
 refs/tags/release-0.1: 1f5c5126e96c79d22cb7862f75304136e204f105
 refs/heads/ndm: f3868061cd7988080c30d6d5bf352a5a5fe2460b
-refs/heads/try2: 6818e241b49c03c0fe0994dbe8340e2d8f482f09
+refs/heads/try2: 4a4646fd54a85f78512e5f2d1d2cd253954d1ea4
 refs/heads/dist-snap: ba4081a5a8573875fed17545846f6f6902c8ba8d
 refs/tags/release-0.2: c870d2dffb391e14efb05aa27898f1f6333a9596
 refs/tags/release-0.3: b5f0d0f648d9a6153664837026ba1be43d3e2503

branches/try2/doc/rust.md

@@ -2187,7 +2187,7 @@ A loop expression denotes an infinite loop;
 see [Continue expressions](#continue-expressions) for continue expressions.
 
 ~~~~~~~~{.ebnf .gram}
-loop_expr : "loop" [ ident ':' ] '{' block '}';
+loop_expr : [ lifetime ':' ] "loop" '{' block '}';
 ~~~~~~~~
 
 A `loop` expression may optionally have a _label_.
@@ -2198,7 +2198,7 @@ See [Break expressions](#break-expressions).
 ### Break expressions
 
 ~~~~~~~~{.ebnf .gram}
-break_expr : "break" [ ident ];
+break_expr : "break" [ lifetime ];
 ~~~~~~~~
 
 A `break` expression has an optional `label`.
@@ -2211,7 +2211,7 @@ but must enclose it.
 ### Continue expressions
 
 ~~~~~~~~{.ebnf .gram}
-continue_expr : "loop" [ ident ];
+continue_expr : "loop" [ lifetime ];
 ~~~~~~~~
 
 A continue expression, written `loop`, also has an optional `label`.
@@ -2393,7 +2393,7 @@ variables in the arm's block, and control enters the block.
 An example of an `match` expression:
 
 
-~~~~
+~~~~ {.xfail-test}
 # fn process_pair(a: int, b: int) { }
 # fn process_ten() { }
 

branches/try2/doc/tutorial-ffi.md

@@ -139,6 +139,74 @@ pub fn uncompress(src: &[u8]) -> Option<~[u8]> {
 For reference, the examples used here are also available as an [library on
 GitHub](https://github.com/thestinger/rust-snappy).
 
+# Destructors
+
+Foreign libraries often hand off ownership of resources to the calling code,
+which should be wrapped in a destructor to provide safety and guarantee their
+release.
+
+A type with the same functionality as owned boxes can be implemented by
+wrapping `malloc` and `free`:
+
+~~~~
+use core::libc::{c_void, size_t, malloc, free};
+
+#[abi = "rust-intrinsic"]
+extern "rust-intrinsic" mod rusti {
+    fn init<T>() -> T;
+}
+
+// a wrapper around the handle returned by the foreign code
+pub struct Unique<T> {
+    priv ptr: *mut T
+}
+
+pub impl<'self, T: Owned> Unique<T> {
+    fn new(value: T) -> Unique<T> {
+        unsafe {
+            let ptr = malloc(core::sys::size_of::<T>() as size_t) as *mut T;
+            assert!(!ptr::is_null(ptr));
+            *ptr = value;
+            Unique{ptr: ptr}
+        }
+    }
+
+    // the 'self lifetime results in the same semantics as `&*x` with ~T
+    fn borrow(&self) -> &'self T {
+        unsafe { cast::transmute(self.ptr) }
+    }
+
+    // the 'self lifetime results in the same semantics as `&mut *x` with ~T
+    fn borrow_mut(&mut self) -> &'self mut T {
+        unsafe { cast::transmute(self.ptr) }
+    }
+}
+
+#[unsafe_destructor]
+impl<T: Owned> Drop for Unique<T> {
+    fn finalize(&self) {
+        unsafe {
+            let mut x = rusti::init(); // dummy value to swap in
+            x <-> *self.ptr; // moving the object out is needed to call the destructor
+            free(self.ptr as *c_void)
+        }
+    }
+}
+
+// A comparison between the built-in ~ and this reimplementation
+fn main() {
+    {
+        let mut x = ~5;
+        *x = 10;
+    } // `x` is freed here
+
+    {
+        let mut y = Unique::new(5);
+        *y.borrow_mut() = 10;
+    } // `y` is freed here
+}
+~~~~
+
 # Linking
 
 In addition to the `#[link_args]` attribute for explicitly passing arguments to the linker, an

branches/try2/doc/tutorial.md

@@ -868,108 +868,27 @@ fn first((value, _): (int, float)) -> int { value }
 
 # Destructors
 
-C-style resource management requires the programmer to match every allocation
-with a free, which means manually tracking the responsibility for cleaning up
-(the owner). Correctness is left to the programmer, and it's easy to get wrong.
+A *destructor* is a function responsible for cleaning up the resources used by
+an object when it is no longer accessible. Destructors can be defined to handle
+the release of resources like files, sockets and heap memory.
 
-The following code demonstrates manual memory management, in order to contrast
-it with Rust's resource management. Rust enforces safety, so the `unsafe`
-keyword is used to explicitly wrap the unsafe code. The keyword is a promise to
-the compiler that unsafety does not leak outside of the unsafe block, and is
-used to create safe concepts on top of low-level code.
+Objects are never accessible after their destructor has been called, so there
+are no dynamic failures from accessing freed resources. When a task fails, the
+destructors of all objects in the task are called.
 
-~~~~
-use core::libc::{calloc, free, size_t};
-
-fn main() {
-    unsafe {
-        let a = calloc(1, int::bytes as size_t);
-
-        let d;
+The `~` sigil represents a unique handle for a memory allocation on the heap:
 
-        {
-            let b = calloc(1, int::bytes as size_t);
-
-            let c = calloc(1, int::bytes as size_t);
-            d = c; // move ownership to d
-
-            free(b);
-        }
-
-        free(d);
-        free(a);
-    }
-}
 ~~~~
-
-Rust uses destructors to handle the release of resources like memory
-allocations, files and sockets. An object will only be destroyed when there is
-no longer any way to access it, which prevents dynamic failures from an attempt
-to use a freed resource. When a task fails, the stack unwinds and the
-destructors of all objects owned by that task are called.
-
-The unsafe code from above can be contained behind a safe API that prevents
-memory leaks or use-after-free:
-
-~~~~
-use core::libc::{calloc, free, c_void, size_t};
-
-struct Blob { priv ptr: *c_void }
-
-impl Blob {
-    fn new() -> Blob {
-        unsafe { Blob{ptr: calloc(1, int::bytes as size_t)} }
-    }
-}
-
-impl Drop for Blob {
-    fn finalize(&self) {
-        unsafe { free(self.ptr); }
-    }
-}
-
-fn main() {
-    let a = Blob::new();
-
-    let d;
-
-    {
-        let b = Blob::new();
-
-        let c = Blob::new();
-        d = c; // move ownership to d
-
-        // b is destroyed here
-    }
-
-    // d is destroyed here
-    // a is destroyed here
+{
+    // an integer allocated on the heap
+    let y = ~10;
 }
+// the destructor frees the heap memory as soon as `y` goes out of scope
 ~~~~
 
-This pattern is common enough that Rust includes dynamically allocated memory
-as first-class types (`~` and `@`). Non-memory resources like files are cleaned
-up with custom destructors.
-
-~~~~
-fn main() {
-    let a = ~0;
-
-    let d;
-
-    {
-        let b = ~0;
-
-        let c = ~0;
-        d = c; // move ownership to d
-
-        // b is destroyed here
-    }
-
-    // d is destroyed here
-    // a is destroyed here
-}
-~~~~
+Rust includes syntax for heap memory allocation in the language since it's
+commonly used, but the same semantics can be implemented by a type with a
+custom destructor.
 
 # Ownership
 
@@ -984,6 +903,22 @@ and destroy the contained object when they go out of scope. A box managed by
 the garbage collector starts a new ownership tree, and the destructor is called
 when it is collected.
 
+~~~~
+// the struct owns the objects contained in the `x` and `y` fields
+struct Foo { x: int, y: ~int }
+
+{
+    // `a` is the owner of the struct, and thus the owner of the struct's fields
+    let a = Foo { x: 5, y: ~10 };
+}
+// when `a` goes out of scope, the destructor for the `~int` in the struct's
+// field is called
+
+// `b` is mutable, and the mutability is inherited by the objects it owns
+let mut b = Foo { x: 5, y: ~10 };
+b.x = 10;
+~~~~
+
 If an object doesn't contain garbage-collected boxes, it consists of a single
 ownership tree and is given the `Owned` trait which allows it to be sent
 between tasks. Custom destructors can only be implemented directly on types
@@ -1007,7 +942,7 @@ refer to that through a pointer.
 ## Owned boxes
 
 An owned box (`~`) is a uniquely owned allocation on the heap. It inherits the
-mutability and lifetime of the owner as it would if there was no box.
+mutability and lifetime of the owner as it would if there was no box:
 
 ~~~~
 let x = 5; // immutable
@@ -1021,8 +956,8 @@ let mut y = ~5; // mutable
 
 The purpose of an owned box is to add a layer of indirection in order to create
 recursive data structures or cheaply pass around an object larger than a
-pointer. Since an owned box has a unique owner, it can be used to represent any
-tree data structure.
+pointer. Since an owned box has a unique owner, it can only be used to
+represent a tree data structure.
 
 The following struct won't compile, because the lack of indirection would mean
 it has an infinite size:
@@ -1092,7 +1027,6 @@ d = b;          // box type is the same, okay
 c = b;          // error
 ~~~~
 
-
 # Move semantics
 
 Rust uses a shallow copy for parameter passing, assignment and returning values
@@ -2047,7 +1981,7 @@ struct TimeBomb {
 
 impl Drop for TimeBomb {
     fn finalize(&self) {
-        for iter::repeat(self.explosivity) {
+        for old_iter::repeat(self.explosivity) {
             io::println("blam!");
         }
     }
@@ -2122,11 +2056,10 @@ method declarations. So, re-declaring the type parameter
 `T` as an explicit type parameter for `len`, in either the trait or
 the impl, would be a compile-time error.
 
-Within a trait definition, `self` is a special type that you can think
+Within a trait definition, `Self` is a special type that you can think
 of as a type parameter. An implementation of the trait for any given
-type `T` replaces the `self` type parameter with `T`. Simply, in a
-trait, `self` is a type, and in an impl, `self` is a value. The
-following trait describes types that support an equality operation:
+type `T` replaces the `Self` type parameter with `T`. The following
+trait describes types that support an equality operation:
 
 ~~~~
 // In a trait, `self` refers to the self argument.
@@ -2142,7 +2075,7 @@ impl Eq for int {
 ~~~~
 
 Notice that in the trait definition, `equals` takes a
-second parameter of type `self`.
+second parameter of type `Self`.
 In contrast, in the `impl`, `equals` takes a second parameter of
 type `int`, only using `self` as the name of the receiver.
 

branches/try2/src/compiletest/common.rs

@@ -8,8 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-use core::prelude::*;
-
 #[deriving(Eq)]
 pub enum mode {
     mode_compile_fail,

branches/try2/src/compiletest/compiletest.rc

@@ -10,14 +10,11 @@
 
 #[crate_type = "bin"];
 
-#[no_core];
-
 #[allow(vecs_implicitly_copyable)];
 #[allow(non_camel_case_types)];
 #[allow(deprecated_mode)];
 #[allow(deprecated_pattern)];
 
-extern mod core(vers = "0.7-pre");
 extern mod std(vers = "0.7-pre");
 
 use core::*;

branches/try2/src/compiletest/errors.rs

@@ -8,12 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-use core::prelude::*;
-
-use core::io;
-use core::io::ReaderUtil;
-use core::str;
-
 pub struct ExpectedError { line: uint, kind: ~str, msg: ~str }
 
 // Load any test directives embedded in the file

branches/try2/src/compiletest/header.rs

@@ -8,16 +8,9 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-use core::prelude::*;
-
 use common;
 use common::config;
 
-use core::io::ReaderUtil;
-use core::io;
-use core::os;
-use core::str;
-
 pub struct TestProps {
     // Lines that should be expected, in order, on standard out
     error_patterns: ~[~str],

branches/try2/src/compiletest/procsrv.rs

@@ -8,16 +8,10 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-use core::prelude::*;
 
-use core::io::{ReaderUtil, WriterUtil};
-use core::io;
 use core::libc::c_int;
-use core::os;
 use core::run::spawn_process;
 use core::run;
-use core::str;
-use core::task;
 
 #[cfg(target_os = "win32")]
 fn target_env(lib_path: ~str, prog: ~str) -> ~[(~str,~str)] {