auto merge of #13117 : alexcrichton/rust/no-crate-map, r=brson

[rust.git] / RELEASES.txt

Version 0.9 (January 2014)
--------------------------

   * ~1800 changes, numerous bugfixes

   * Language
      * The `float` type has been removed. Use `f32` or `f64` instead.
      * A new facility for enabling experimental features (feature gating) has
        been added, using the crate-level `#[feature(foo)]` attribute.
      * Managed boxes (@) are now behind a feature gate
        (`#[feature(managed_boxes)]`) in preperation for future removal. Use the
        standard library's `Gc` or `Rc` types instead.
      * `@mut` has been removed. Use `std::cell::{Cell, RefCell}` instead.
      * Jumping back to the top of a loop is now done with `continue` instead of
        `loop`.
      * Strings can no longer be mutated through index assignment.
      * Raw strings can be created via the basic `r"foo"` syntax or with matched
        hash delimiters, as in `r###"foo"###`.
      * `~fn` is now written `proc (args) -> retval { ... }` and may only be
        called once.
      * The `&fn` type is now written `|args| -> ret` to match the literal form.
      * `@fn`s have been removed.
      * `do` only works with procs in order to make it obvious what the cost
        of `do` is.
      * Single-element tuple-like structs can no longer be dereferenced to
        obtain the inner value. A more comprehensive solution for overloading
        the dereference operator will be provided in the future.
      * The `#[link(...)]` attribute has been replaced with
        `#[crate_id = "name#vers"]`.
      * Empty `impl`s must be terminated with empty braces and may not be
        terminated with a semicolon.
      * Keywords are no longer allowed as lifetime names; the `self` lifetime
        no longer has any special meaning.
      * The old `fmt!` string formatting macro has been removed.
      * `printf!` and `printfln!` (old-style formatting) removed in favor of
        `print!` and `println!`.
      * `mut` works in patterns now, as in `let (mut x, y) = (1, 2);`.
      * The `extern mod foo (name = "bar")` syntax has been removed. Use
        `extern mod foo = "bar"` instead.
      * New reserved keywords: `alignof`, `offsetof`, `sizeof`.
      * Macros can have attributes.
      * Macros can expand to items with attributes.
      * Macros can expand to multiple items.
      * The `asm!` macro is feature-gated (`#[feature(asm)]`).
      * Comments may be nested.
      * Values automatically coerce to trait objects they implement, without
        an explicit `as`.
      * Enum discriminants are no longer an entire word but as small as needed to
        contain all the variants. The `repr` attribute can be used to override
        the discriminant size, as in `#[repr(int)]` for integer-sized, and
        `#[repr(C)]` to match C enums.
      * Non-string literals are not allowed in attributes (they never worked).
      * The FFI now supports variadic functions.
      * Octal numeric literals, as in `0o7777`.
      * The `concat!` syntax extension performs compile-time string concatenation.
      * The `#[fixed_stack_segment]` and `#[rust_stack]` attributes have been
        removed as Rust no longer uses segmented stacks.
      * Non-ascii identifiers are feature-gated (`#[feature(non_ascii_idents)]`).
      * Ignoring all fields of an enum variant or tuple-struct is done with `..`,
        not `*`; ignoring remaining fields of a struct is also done with `..`,
        not `_`; ignoring a slice of a vector is done with `..`, not `.._`.
      * `rustc` supports the "win64" calling convention via `extern "win64"`.
      * `rustc` supports the "system" calling convention, which defaults to the
        preferred convention for the target platform, "stdcall" on 32-bit Windows,
        "C" elsewhere.
      * The `type_overflow` lint (default: warn) checks literals for overflow.
      * The `unsafe_block` lint (default: allow) checks for usage of `unsafe`.
      * The `attribute_usage` lint (default: warn) warns about unknown
        attributes.
      * The `unknown_features` lint (default: warn) warns about unknown
        feature gates.
      * The `dead_code` lint (default: warn) checks for dead code.
      * Rust libraries can be linked statically to one another
      * `#[link_args]` is behind the `link_args` feature gate.
      * Native libraries are now linked with `#[link(name = "foo")]`
      * Native libraries can be statically linked to a rust crate
        (`#[link(name = "foo", kind = "static")]`).
      * Native OS X frameworks are now officially supported
        (`#[link(name = "foo", kind = "framework")]`).
      * The `#[thread_local]` attribute creates thread-local (not task-local)
        variables. Currently behind the `thread_local` feature gate.
      * The `return` keyword may be used in closures.
      * Types that can be copied via a memcpy implement the `Pod` kind.
      * The `cfg` attribute can now be used on struct fields and enum variants.

   * Libraries
      * std: The `option` and `result` API's have been overhauled to make them
        simpler, more consistent, and more composable.
      * std: The entire `std::io` module has been replaced with one that is
        more comprehensive and that properly interfaces with the underlying
        scheduler. File, TCP, UDP, Unix sockets, pipes, and timers are all
        implemented.
      * std: `io::util` contains a number of useful implementations of
        `Reader` and `Writer`, including `NullReader`, `NullWriter`,
        `ZeroReader`, `TeeReader`.
      * std: The reference counted pointer type `extra::rc` moved into std.
      * std: The `Gc` type in the `gc` module will replace `@` (it is currently
        just a wrapper around it).
      * std: The `Either` type has been removed.
      * std: `fmt::Default` can be implemented for any type to provide default
        formatting to the `format!` macro, as in `format!("{}", myfoo)`.
      * std: The `rand` API continues to be tweaked.
      * std: The `rust_begin_unwind` function, useful for insterting breakpoints
        on failure in gdb, is now named `rust_fail`.
      * std: The `each_key` and `each_value` methods on `HashMap` have been
        replaced by the `keys` and `values` iterators.
      * std: Functions dealing with type size and alignment have moved from the
        `sys` module to the `mem` module.
      * std: The `path` module was written and API changed.
      * std: `str::from_utf8` has been changed to cast instead of allocate.
      * std: `starts_with` and `ends_with` methods added to vectors via the
        `ImmutableEqVector` trait, which is in the prelude.
      * std: Vectors can be indexed with the `get_opt` method, which returns `None`
        if the index is out of bounds.
      * std: Task failure no longer propagates between tasks, as the model was
        complex, expensive, and incompatible with thread-based tasks.
      * std: The `Any` type can be used for dynamic typing.
      * std: `~Any` can be passed to the `fail!` macro and retrieved via
        `task::try`.
      * std: Methods that produce iterators generally do not have an `_iter`
        suffix now.
      * std: `cell::Cell` and `cell::RefCell` can be used to introduce mutability
        roots (mutable fields, etc.). Use instead of e.g. `@mut`.
      * std: `util::ignore` renamed to `prelude::drop`.
      * std: Slices have `sort` and `sort_by` methods via the `MutableVector`
        trait.
      * std: `vec::raw` has seen a lot of cleanup and API changes.
      * std: The standard library no longer includes any C++ code, and very
        minimal C, eliminating the dependency on libstdc++.
      * std: Runtime scheduling and I/O functionality has been factored out into
        extensible interfaces and is now implemented by two different crates:
        libnative, for native threading and I/O; and libgreen, for green threading
        and I/O. This paves the way for using the standard library in more limited
        embeded environments.
      * std: The `comm` module has been rewritten to be much faster, have a
        simpler, more consistent API, and to work for both native and green
        threading.
      * std: All libuv dependencies have been moved into the rustuv crate.
      * native: New implementations of runtime scheduling on top of OS threads.
      * native: New native implementations of TCP, UDP, file I/O, process spawning,
        and other I/O.
      * green: The green thread scheduler and message passing types are almost
        entirely lock-free.
      * extra: The `flatpipes` module had bitrotted and was removed.
      * extra: All crypto functions have been removed and Rust now has a policy of
        not reimplementing crypto in the standard library. In the future crypto
        will be provided by external crates with bindings to established libraries.
      * extra: `c_vec` has been modernized.
      * extra: The `sort` module has been removed. Use the `sort` method on
        mutable slices.

   * Tooling
      * The `rust` and `rusti` commands have been removed, due to lack of
        maintenance.
      * `rustdoc` was completely rewritten.
      * `rustdoc` can test code examples in documentation.
      * `rustpkg` can test packages with the argument, 'test'.
      * `rustpkg` supports arbitrary dependencies, including C libraries.
      * `rustc`'s support for generating debug info is improved again.
      * `rustc` has better error reporting for unbalanced delimiters.
      * `rustc`'s JIT support was removed due to bitrot.
      * Executables and static libraries can be built with LTO (-Z lto)
      * `rustc` adds a `--dep-info` flag for communicating dependencies to
        build tools.

Version 0.8 (September 2013)
--------------------------

   * ~2200 changes, numerous bugfixes

   * Language
      * The `for` loop syntax has changed to work with the `Iterator` trait.
      * At long last, unwinding works on Windows.
      * Default methods are ready for use.
      * Many trait inheritance bugs fixed.
      * Owned and borrowed trait objects work more reliably.
      * `copy` is no longer a keyword. It has been replaced by the `Clone` trait.
      * rustc can omit emission of code for the `debug!` macro if it is passed
        `--cfg ndebug`
      * mod.rs is now "blessed". When loading `mod foo;`, rustc will now look
        for foo.rs, then foo/mod.rs, and will generate an error when both are
        present.
      * Strings no longer contain trailing nulls. The new `std::c_str` module
        provides new mechanisms for converting to C strings.
      * The type of foreign functions is now `extern "C" fn` instead of `*u8'.
      * The FFI has been overhauled such that foreign functions are called directly,
        instead of through a stack-switching wrapper.
      * Calling a foreign function must be done through a Rust function with the
        `#[fixed_stack_segment]` attribute.
      * The `externfn!` macro can be used to declare both a foreign function and
        a `#[fixed_stack_segment]` wrapper at once.
      * `pub` and `priv` modifiers on `extern` blocks are no longer parsed.
      * `unsafe` is no longer allowed on extern fns - they are all unsafe.
      * `priv` is disallowed everywhere except for struct fields and enum variants.
      * `&T` (besides `&'static T`) is no longer allowed in `@T`.
      * `ref` bindings in irrefutable patterns work correctly now.
      * `char` is now prevented from containing invalid code points.
      * Casting to `bool` is no longer allowed.
      * `\0` is now accepted as an escape in chars and strings.
      * `yield` is a reserved keyword.
      * `typeof` is a reserved keyword.
      * Crates may be imported by URL with `extern mod foo = "url";`.
      * Explicit enum discriminants may be given as uints as in `enum E { V = 0u }`
      * Static vectors can be initialized with repeating elements,
        e.g. `static foo: [u8, .. 100]: [0, .. 100];`.
      * Static structs can be initialized with functional record update,
        e.g. `static foo: Foo = Foo { a: 5, .. bar };`.
      * `cfg!` can be used to conditionally execute code based on the crate
        configuration, similarly to `#[cfg(...)]`.
      * The `unnecessary_qualification` lint detects unneeded module
        prefixes (default: allow).
      * Arithmetic operations have been implemented on the SIMD types in
        `std::unstable::simd`.
      * Exchange allocation headers were removed, reducing memory usage.
      * `format!` implements a completely new, extensible, and higher-performance
        string formatting system. It will replace `fmt!`.
      * `print!` and `println!` write formatted strings (using the `format!`
        extension) to stdout.
      * `write!` and `writeln!` write formatted strings (using the `format!`
        extension) to the new Writers in `std::rt::io`.
      * The library section in which a function or static is placed may
        be specified with `#[link_section = "..."]`.
      * The `proto!` syntax extension for defining bounded message protocols
        was removed.
      * `macro_rules!` is hygienic for `let` declarations.
      * The `#[export_name]` attribute specifies the name of a symbol.
      * `unreachable!` can be used to indicate unreachable code, and fails
        if executed.

   * Libraries
      * std: Transitioned to the new runtime, written in Rust.
      * std: Added an experimental I/O library, `rt::io`, based on the new
        runtime.
      * std: A new generic `range` function was added to the prelude, replacing
        `uint::range` and friends.
      * std: `range_rev` no longer exists. Since range is an iterator it can be
        reversed with `range(lo, hi).invert()`.
      * std: The `chain` method on option renamed to `and_then`; `unwrap_or_default`
        renamed to `unwrap_or`.
      * std: The `iterator` module was renamed to `iter`.
      * std: Integral types now support the `checked_add`, `checked_sub`, and
        `checked_mul` operations for detecting overflow.
      * std: Many methods in `str`, `vec`, `option, `result` were renamed for
        consistency.
      * std: Methods are standardizing on conventions for casting methods:
        `to_foo` for copying, `into_foo` for moving, `as_foo` for temporary
        and cheap casts.
      * std: The `CString` type in `c_str` provides new ways to convert to and
        from C strings.
      * std: `DoubleEndedIterator` can yield elements in two directions.
      * std: The `mut_split` method on vectors partitions an `&mut [T]` into
        two splices.
      * std: `str::from_bytes` renamed to `str::from_utf8`.
      * std: `pop_opt` and `shift_opt` methods added to vectors.
      * std: The task-local data interface no longer uses @, and keys are
        no longer function pointers.
      * std: The `swap_unwrap` method of `Option` renamed to `take_unwrap`.
      * std: Added `SharedPort` to `comm`.
      * std: `Eq` has a default method for `ne`; only `eq` is required
        in implementations.
      * std: `Ord` has default methods for `le`, `gt` and `ge`; only `lt`
        is required in implementations.
      * std: `is_utf8` performance is improved, impacting many string functions.
      * std: `os::MemoryMap` provides cross-platform mmap.
      * std: `ptr::offset` is now unsafe, but also more optimized. Offsets that
        are not 'in-bounds' are considered undefined.
      * std: Many freestanding functions in `vec` removed in favor of methods.
      * std: Many freestanding functions on scalar types removed in favor of
        methods.
      * std: Many options to task builders were removed since they don't make
        sense in the new scheduler design.
      * std: More containers implement `FromIterator` so can be created by the
        `collect` method.
      * std: More complete atomic types in `unstable::atomics`.
      * std: `comm::PortSet` removed.
      * std: Mutating methods in the `Set` and `Map` traits have been moved into
        the `MutableSet` and `MutableMap` traits. `Container::is_empty`,
        `Map::contains_key`, `MutableMap::insert`, and `MutableMap::remove` have
        default implementations.
      * std: Various `from_str` functions were removed in favor of a generic
        `from_str` which is available in the prelude.
      * std: `util::unreachable` removed in favor of the `unreachable!` macro.
      * extra: `dlist`, the doubly-linked list was modernized.
      * extra: Added a `hex` module with `ToHex` and `FromHex` traits.
      * extra: Added `glob` module, replacing `std::os::glob`.
      * extra: `rope` was removed.
      * extra: `deque` was renamed to `ringbuf`. `RingBuf` implements `Deque`.
      * extra: `net`, and `timer` were removed. The experimental replacements
        are `std::rt::io::net` and `std::rt::io::timer`.
      * extra: Iterators implemented for `SmallIntMap`.
      * extra: Iterators implemented for `Bitv` and `BitvSet`.
      * extra: `SmallIntSet` removed. Use `BitvSet`.
      * extra: Performance of JSON parsing greatly improved.
      * extra: `semver` updated to SemVer 2.0.0.
      * extra: `term` handles more terminals correctly.
      * extra: `dbg` module removed.
      * extra: `par` module removed.
      * extra: `future` was cleaned up, with some method renames.
      * extra: Most free functions in `getopts` were converted to methods.

   * Other
      * rustc's debug info generation (`-Z debug-info`) is greatly improved.
      * rustc accepts `--target-cpu` to compile to a specific CPU architecture,
        similarly to gcc's `--march` flag.
      * rustc's performance compiling small crates is much better.
      * rustpkg has received many improvements.
      * rustpkg supports git tags as package IDs.
      * rustpkg builds into target-specific directories so it can be used for
        cross-compiling.
      * The number of concurrent test tasks is controlled by the environment
        variable RUST_TEST_TASKS.
      * The test harness can now report metrics for benchmarks.
      * All tools have man pages.
      * Programs compiled with `--test` now support the `-h` and `--help` flags.
      * The runtime uses jemalloc for allocations.
      * Segmented stacks are temporarily disabled as part of the transition to
        the new runtime. Stack overflows are possible!
      * A new documentation backend, rustdoc_ng, is available for use. It is
        still invoked through the normal `rustdoc` command.

Version 0.7 (July 2013)
-----------------------

   * ~2000 changes, numerous bugfixes

   * Language
      * `impl`s no longer accept a visibility qualifier. Put them on methods
        instead.
      * The borrow checker has been rewritten with flow-sensitivity, fixing
        many bugs and inconveniences.
      * The `self` parameter no longer implicitly means `&'self self`,
        and can be explicitly marked with a lifetime.
      * Overloadable compound operators (`+=`, etc.) have been temporarily
        removed due to bugs.
      * The `for` loop protocol now requires `for`-iterators to return `bool`
        so they compose better.
      * The `Durable` trait is replaced with the `'static` bounds.
      * Trait default methods work more often.
      * Structs with the `#[packed]` attribute have byte alignment and
        no padding between fields.
      * Type parameters bound by `Copy` must now be copied explicitly with
        the `copy` keyword.
      * It is now illegal to move out of a dereferenced unsafe pointer.
      * `Option<~T>` is now represented as a nullable pointer.
      * `@mut` does dynamic borrow checks correctly.
      * The `main` function is only detected at the topmost level of the crate.
        The `#[main]` attribute is still valid anywhere.
      * Struct fields may no longer be mutable. Use inherited mutability.
      * The `#[no_send]` attribute makes a type that would otherwise be
        `Send`, not.
      * The `#[no_freeze]` attribute makes a type that would otherwise be
        `Freeze`, not.
      * Unbounded recursion will abort the process after reaching the limit
        specified by the `RUST_MAX_STACK` environment variable (default: 1GB).
      * The `vecs_implicitly_copyable` lint mode has been removed. Vectors
        are never implicitly copyable.
      * `#[static_assert]` makes compile-time assertions about static bools.
      * At long last, 'argument modes' no longer exist.
      * The rarely used `use mod` statement no longer exists.

   * Syntax extensions
      * `fail!` and `assert!` accept `~str`, `&'static str` or `fmt!`-style
        argument list.
      * `Encodable`, `Decodable`, `Ord`, `TotalOrd`, `TotalEq`, `DeepClone`,
        `Rand`, `Zero` and `ToStr` can all be automatically derived with
        `#[deriving(...)]`.
      * The `bytes!` macro returns a vector of bytes for string, u8, char,
        and unsuffixed integer literals.

   * Libraries
      * The `core` crate was renamed to `std`.
      * The `std` crate was renamed to `extra`.
      * More and improved documentation.
      * std: `iterator` module for external iterator objects.
      * Many old-style (internal, higher-order function) iterators replaced by
        implementations of `Iterator`.
      * std: Many old internal vector and string iterators,
        incl. `any`, `all`. removed.
      * std: The `finalize` method of `Drop` renamed to `drop`.
      * std: The `drop` method now takes `&mut self` instead of `&self`.
      * std: The prelude no longer reexports any modules, only types and traits.
      * std: Prelude additions: `print`, `println`, `FromStr`, `ApproxEq`, `Equiv`,
        `Iterator`, `IteratorUtil`, many numeric traits, many tuple traits.
      * std: New numeric traits: `Fractional`, `Real`, `RealExt`, `Integer`, `Ratio`,
        `Algebraic`, `Trigonometric`, `Exponential`, `Primitive`.
      * std: Tuple traits and accessors defined for up to 12-tuples, e.g.
        `(0, 1, 2).n2()` or `(0, 1, 2).n2_ref()`.
      * std: Many types implement `Clone`.
      * std: `path` type renamed to `Path`.
      * std: `mut` module and `Mut` type removed.
      * std: Many standalone functions removed in favor of methods and iterators
        in `vec`, `str`. In the future methods will also work as functions.
      * std: `reinterpret_cast` removed. Use `transmute`.
      * std: ascii string handling in `std::ascii`.
      * std: `Rand` is implemented for ~/@.
      * std: `run` module for spawning processes overhauled.
      * std: Various atomic types added to `unstable::atomic`.
      * std: Various types implement `Zero`.
      * std: `LinearMap` and `LinearSet` renamed to `HashMap` and `HashSet`.
      * std: Borrowed pointer functions moved from `ptr` to `borrow`.
      * std: Added `os::mkdir_recursive`.
      * std: Added `os::glob` function performs filesystems globs.
      * std: `FuzzyEq` renamed to `ApproxEq`.
      * std: `Map` now defines `pop` and `swap` methods.
      * std: `Cell` constructors converted to static methods.
      * extra: `rc` module adds the reference counted pointers, `Rc` and `RcMut`.
      * extra: `flate` module moved from `std` to `extra`.
      * extra: `fileinput` module for iterating over a series of files.
      * extra: `Complex` number type and `complex` module.
      * extra: `Rational` number type and `rational` module.
      * extra: `BigInt`, `BigUint` implement numeric and comparison traits.
      * extra: `term` uses terminfo now, is more correct.
      * extra: `arc` functions converted to methods.
      * extra: Implementation of fixed output size variations of SHA-2.

   * Tooling
      * `unused_variable`  lint mode for unused variables (default: warn).
      * `unused_unsafe` lint mode for detecting unnecessary `unsafe` blocks
        (default: warn).
      * `unused_mut` lint mode for identifying unused `mut` qualifiers
        (default: warn).
      * `dead_assignment` lint mode for unread variables (default: warn).
      * `unnecessary_allocation` lint mode detects some heap allocations that are
        immediately borrowed so could be written without allocating (default: warn).
      * `missing_doc` lint mode (default: allow).
      * `unreachable_code` lint mode (default: warn).
      * The `rusti` command has been rewritten and a number of bugs addressed.
      * rustc outputs in color on more terminals.
      * rustc accepts a `--link-args` flag to pass arguments to the linker.
      * rustc accepts a `-Z print-link-args` flag for debugging linkage.
      * Compiling with `-g` will make the binary record information about
        dynamic borrowcheck failures for debugging.
      * rustdoc has a nicer stylesheet.
      * Various improvements to rustdoc.
      * Improvements to rustpkg (see the detailed release notes).

Version 0.6 (April 2013)
------------------------

   * ~2100 changes, numerous bugfixes

   * Syntax changes
      * The self type parameter in traits is now spelled `Self`
      * The `self` parameter in trait and impl methods must now be explicitly
        named (for example: `fn f(&self) { }`). Implicit self is deprecated.
      * Static methods no longer require the `static` keyword and instead
        are distinguished by the lack of a `self` parameter
      * Replaced the `Durable` trait with the `'static` lifetime
      * The old closure type syntax with the trailing sigil has been
        removed in favor of the more consistent leading sigil
      * `super` is a keyword, and may be prefixed to paths
      * Trait bounds are separated with `+` instead of whitespace
      * Traits are implemented with `impl Trait for Type`
        instead of `impl Type: Trait`
      * Lifetime syntax is now `&'l foo` instead of `&l/foo`
      * The `export` keyword has finally been removed
      * The `move` keyword has been removed (see "Semantic changes")
      * The interior mutability qualifier on vectors, `[mut T]`, has been
        removed. Use `&mut [T]`, etc.
      * `mut` is no longer valid in `~mut T`. Use inherited mutability
      * `fail` is no longer a keyword. Use `fail!()`
      * `assert` is no longer a keyword. Use `assert!()`
      * `log` is no longer a keyword. use `debug!`, etc.
      * 1-tuples may be represented as `(T,)`
      * Struct fields may no longer be `mut`. Use inherited mutability,
        `@mut T`, `core::mut` or `core::cell`
      * `extern mod { ... }` is no longer valid syntax for foreign
        function modules. Use extern blocks: `extern { ... }`
      * Newtype enums removed. Use tuple-structs.
      * Trait implementations no longer support visibility modifiers
      * Pattern matching over vectors improved and expanded
      * `const` renamed to `static` to correspond to lifetime name,
        and make room for future `static mut` unsafe mutable globals.
      * Replaced `#[deriving_eq]` with `#[deriving(Eq)]`, etc.
      * `Clone` implementations can be automatically generated with
        `#[deriving(Clone)]`
      * Casts to traits must use a pointer sigil, e.g. `@foo as @Bar`
        instead of `foo as Bar`.
      * Fixed length vector types are now written as `[int, .. 3]`
        instead of `[int * 3]`.
      * Fixed length vector types can express the length as a constant
        expression. (ex: `[int, .. GL_BUFFER_SIZE - 2]`)

   * Semantic changes
      * Types with owned pointers or custom destructors move by default,
        eliminating the `move` keyword
      * All foreign functions are considered unsafe
      * &mut is now unaliasable
      * Writes to borrowed @mut pointers are prevented dynamically
      * () has size 0
      * The name of the main function can be customized using #[main]
      * The default type of an inferred closure is &fn instead of @fn
      * `use` statements may no longer be "chained" - they cannot import
        identifiers imported by previous `use` statements
      * `use` statements are crate relative, importing from the "top"
        of the crate by default. Paths may be prefixed with `super::`
        or `self::` to change the search behavior.
      * Method visibility is inherited from the implementation declaration
      * Structural records have been removed
      * Many more types can be used in static items, including enums
        'static-lifetime pointers and vectors
      * Pattern matching over vectors improved and expanded
      * Typechecking of closure types has been overhauled to
        improve inference and eliminate unsoundness
      * Macros leave scope at the end of modules, unless that module is
        tagged with #[macro_escape]

   * Libraries
      * Added big integers to `std::bigint`
      * Removed `core::oldcomm` module
      * Added pipe-based `core::comm` module
      * Numeric traits have been reorganized under `core::num`
      * `vec::slice` finally returns a slice
      * `debug!` and friends don't require a format string, e.g. `debug!(Foo)`
      * Containers reorganized around traits in `core::container`
      * `core::dvec` removed, `~[T]` is a drop-in replacement
      * `core::send_map` renamed to `core::hashmap`
      * `std::map` removed; replaced with `core::hashmap`
      * `std::treemap` reimplemented as an owned balanced tree
      * `std::deque` and `std::smallintmap` reimplemented as owned containers
      * `core::trie` added as a fast ordered map for integer keys
      * Set types added to `core::hashmap`, `core::trie` and `std::treemap`
      * `Ord` split into `Ord` and `TotalOrd`. `Ord` is still used to
        overload the comparison operators, whereas `TotalOrd` is used
        by certain container types

   * Other
      * Replaced the 'cargo' package manager with 'rustpkg'
      * Added all-purpose 'rust' tool
      * `rustc --test` now supports benchmarks with the `#[bench]` attribute
      * rustc now *attempts* to offer spelling suggestions
      * Improved support for ARM and Android
      * Preliminary MIPS backend
      * Improved foreign function ABI implementation for x86, x86_64
      * Various memory usage improvements
      * Rust code may be embedded in foreign code under limited circumstances
      * Inline assembler supported by new asm!() syntax extension.

Version 0.5 (December 2012)
---------------------------

   * ~900 changes, numerous bugfixes

   * Syntax changes
      * Removed `<-` move operator
      * Completed the transition from the `#fmt` extension syntax to `fmt!`
      * Removed old fixed length vector syntax - `[T]/N`
      * New token-based quasi-quoters, `quote_tokens!`, `quote_expr!`, etc.
      * Macros may now expand to items and statements
      * `a.b()` is always parsed as a method call, never as a field projection
      * `Eq` and `IterBytes` implementations can be automatically generated
        with `#[deriving_eq]` and `#[deriving_iter_bytes]` respectively
      * Removed the special crate language for `.rc` files
      * Function arguments may consist of any irrefutable pattern

   * Semantic changes
      * `&` and `~` pointers may point to objects
      * Tuple structs - `struct Foo(Bar, Baz)`. Will replace newtype enums.
      * Enum variants may be structs
      * Destructors can be added to all nominal types with the Drop trait
      * Structs and nullary enum variants may be constants
      * Values that cannot be implicitly copied are now automatically moved
        without writing `move` explicitly
      * `&T` may now be coerced to `*T`
      * Coercions happen in `let` statements as well as function calls
      * `use` statements now take crate-relative paths
      * The module and type namespaces have been merged so that static
        method names can be resolved under the trait in which they are
        declared

   * Improved support for language features
      * Trait inheritance works in many scenarios
      * More support for explicit self arguments in methods - `self`, `&self`
        `@self`, and `~self` all generally work as expected
      * Static methods work in more situations
      * Experimental: Traits may declare default methods for the implementations
        to use

   * Libraries
      * New condition handling system in `core::condition`
      * Timsort added to `std::sort`
      * New priority queue, `std::priority_queue`
      * Pipes for serializable types, `std::flatpipes'
      * Serialization overhauled to be trait-based
      * Expanded `getopts` definitions
      * Moved futures to `std`
      * More functions are pure now
      * `core::comm` renamed to `oldcomm`. Still deprecated
      * `rustdoc` and `cargo` are libraries now

   * Misc
      * Added a preliminary REPL, `rusti`
      * License changed from MIT to dual MIT/APL2

Version 0.4 (October 2012)
--------------------------

   * ~2000 changes, numerous bugfixes

   * Syntax
      * All keywords are now strict and may not be used as identifiers anywhere
      * Keyword removal: 'again', 'import', 'check', 'new', 'owned', 'send',
        'of', 'with', 'to', 'class'.
      * Classes are replaced with simpler structs
      * Explicit method self types
      * `ret` became `return` and `alt` became `match`
      * `import` is now `use`; `use is now `extern mod`
      * `extern mod { ... }` is now `extern { ... }`
      * `use mod` is the recommended way to import modules
      * `pub` and `priv` replace deprecated export lists
      * The syntax of `match` pattern arms now uses fat arrow (=>)
      * `main` no longer accepts an args vector; use `os::args` instead

   * Semantics
      * Trait implementations are now coherent, ala Haskell typeclasses
      * Trait methods may be static
      * Argument modes are deprecated
      * Borrowed pointers are much more mature and recommended for use
      * Strings and vectors in the static region are stored in constant memory
      * Typestate was removed
      * Resolution rewritten to be more reliable
      * Support for 'dual-mode' data structures (freezing and thawing)

   * Libraries
      * Most binary operators can now be overloaded via the traits in
        `core::ops'
      * `std::net::url` for representing URLs
      * Sendable hash maps in `core::send_map`
      * `core::task' gained a (currently unsafe) task-local storage API

   * Concurrency
      * An efficient new intertask communication primitive called the pipe,
        along with a number of higher-level channel types, in `core::pipes`
      * `std::arc`, an atomically reference counted, immutable, shared memory
        type
      * `std::sync`, various exotic synchronization tools based on arcs and pipes
      * Futures are now based on pipes and sendable
      * More robust linked task failure
      * Improved task builder API

   * Other
      * Improved error reporting
      * Preliminary JIT support
      * Preliminary work on precise GC
      * Extensive architectural improvements to rustc
      * Begun a transition away from buggy C++-based reflection (shape) code to
        Rust-based (visitor) code
      * All hash functions and tables converted to secure, randomized SipHash

Version 0.3  (July 2012)
------------------------

   * ~1900 changes, numerous bugfixes

   * New coding conveniences
      * Integer-literal suffix inference
      * Per-item control over warnings, errors
      * #[cfg(windows)] and #[cfg(unix)] attributes
      * Documentation comments
      * More compact closure syntax
      * 'do' expressions for treating higher-order functions as
        control structures
      * *-patterns (wildcard extended to all constructor fields)

   * Semantic cleanup
      * Name resolution pass and exhaustiveness checker rewritten
      * Region pointers and borrow checking supersede alias
        analysis
      * Init-ness checking is now provided by a region-based liveness
        pass instead of the typestate pass; same for last-use analysis
      * Extensive work on region pointers

   * Experimental new language features
      * Slices and fixed-size, interior-allocated vectors
      * #!-comments for lang versioning, shell execution
      * Destructors and iface implementation for classes;
        type-parameterized classes and class methods
      * 'const' type kind for types that can be used to implement
        shared-memory concurrency patterns

   * Type reflection

   * Removal of various obsolete features
      * Keywords: 'be', 'prove', 'syntax', 'note', 'mutable', 'bind',
                 'crust', 'native' (now 'extern'), 'cont' (now 'again')

      * Constructs: do-while loops ('do' repurposed), fn binding,
                    resources (replaced by destructors)

   * Compiler reorganization
      * Syntax-layer of compiler split into separate crate
      * Clang (from LLVM project) integrated into build
      * Typechecker split into sub-modules

   * New library code
      * New time functions
      * Extension methods for many built-in types
      * Arc: atomic-refcount read-only / exclusive-use shared cells
      * Par: parallel map and search routines
      * Extensive work on libuv interface
      * Much vector code moved to libraries
      * Syntax extensions: #line, #col, #file, #mod, #stringify,
        #include, #include_str, #include_bin

   * Tool improvements
      * Cargo automatically resolves dependencies

Version 0.2  (March 2012)
-------------------------

   * >1500 changes, numerous bugfixes

   * New docs and doc tooling

   * New port: FreeBSD x86_64

   * Compilation model enhancements
      * Generics now specialized, multiply instantiated
      * Functions now inlined across separate crates

   * Scheduling, stack and threading fixes
      * Noticeably improved message-passing performance
      * Explicit schedulers
      * Callbacks from C
      * Helgrind clean

   * Experimental new language features
      * Operator overloading
      * Region pointers
      * Classes

   * Various language extensions
      * C-callback function types: 'crust fn ...'
      * Infinite-loop construct: 'loop { ... }'
      * Shorten 'mutable' to 'mut'
      * Required mutable-local qualifier: 'let mut ...'
      * Basic glob-exporting: 'export foo::*;'
      * Alt now exhaustive, 'alt check' for runtime-checked
      * Block-function form of 'for' loop, with 'break' and 'ret'.

   * New library code
      * AST quasi-quote syntax extension
      * Revived libuv interface
      * New modules: core::{future, iter}, std::arena
      * Merged per-platform std::{os*, fs*} to core::{libc, os}
      * Extensive cleanup, regularization in libstd, libcore

Version 0.1  (January 20, 2012)
-------------------------------

   * Most language features work, including:
      * Unique pointers, unique closures, move semantics
      * Interface-constrained generics
      * Static interface dispatch
      * Stack growth
      * Multithread task scheduling
      * Typestate predicates
      * Failure unwinding, destructors
      * Pattern matching and destructuring assignment
      * Lightweight block-lambda syntax
      * Preliminary macro-by-example

   * Compiler works with the following configurations:
      * Linux: x86 and x86_64 hosts and targets
      * MacOS: x86 and x86_64 hosts and targets
      * Windows: x86 hosts and targets

   * Cross compilation / multi-target configuration supported.

   * Preliminary API-documentation and package-management tools included.

Known issues:

   * Documentation is incomplete.

   * Performance is below intended target.

   * Standard library APIs are subject to extensive change, reorganization.

   * Language-level versioning is not yet operational - future code will
     break unexpectedly.