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Alex Crichton 511f0b8a3d std: Stabilize the std::hash module This commit aims to prepare the `std::hash` module for alpha by formalizing its current interface whileholding off on adding `#[stable]` to the new APIs. The current usage with the `HashMap` and `HashSet` types is also reconciled by separating out composable parts of the design. The primary goal of this slight redesign is to separate the concepts of a hasher's state from a hashing algorithm itself. The primary change of this commit is to separate the `Hasher` trait into a `Hasher` and a `HashState` trait. Conceptually the old `Hasher` trait was actually just a factory for various states, but hashing had very little control over how these states were used. Additionally the old `Hasher` trait was actually fairly unrelated to hashing. This commit redesigns the existing `Hasher` trait to match what the notion of a `Hasher` normally implies with the following definition: trait Hasher { type Output; fn reset(&mut self); fn finish(&self) -> Output; } This `Hasher` trait emphasizes that hashing algorithms may produce outputs other than a `u64`, so the output type is made generic. Other than that, however, very little is assumed about a particular hasher. It is left up to implementors to provide specific methods or trait implementations to feed data into a hasher. The corresponding `Hash` trait becomes: trait Hash<H: Hasher> { fn hash(&self, &mut H); } The old default of `SipState` was removed from this trait as it's not something that we're willing to stabilize until the end of time, but the type parameter is always required to implement `Hasher`. Note that the type parameter `H` remains on the trait to enable multidispatch for specialization of hashing for particular hashers. Note that `Writer` is not mentioned in either of `Hash` or `Hasher`, it is simply used as part `derive` and the implementations for all primitive types. With these definitions, the old `Hasher` trait is realized as a new `HashState` trait in the `collections::hash_state` module as an unstable addition for now. The current definition looks like: trait HashState { type Hasher: Hasher; fn hasher(&self) -> Hasher; } The purpose of this trait is to emphasize that the one piece of functionality for implementors is that new instances of `Hasher` can be created. This conceptually represents the two keys from which more instances of a `SipHasher` can be created, and a `HashState` is what's stored in a `HashMap`, not a `Hasher`. Implementors of custom hash algorithms should implement the `Hasher` trait, and only hash algorithms intended for use in hash maps need to implement or worry about the `HashState` trait. The entire module and `HashState` infrastructure remains `#[unstable]` due to it being recently redesigned, but some other stability decision made for the `std::hash` module are: * The `Writer` trait remains `#[experimental]` as it's intended to be replaced with an `io::Writer` (more details soon). * The top-level `hash` function is `#[unstable]` as it is intended to be generic over the hashing algorithm instead of hardwired to `SipHasher` * The inner `sip` module is now private as its one export, `SipHasher` is reexported in the `hash` module. And finally, a few changes were made to the default parameters on `HashMap`. * The `RandomSipHasher` default type parameter was renamed to `RandomState`. This renaming emphasizes that it is not a hasher, but rather just state to generate hashers. It also moves away from the name "sip" as it may not always be implemented as `SipHasher`. This type lives in the `std::collections::hash_map` module as `#[unstable]` * The associated `Hasher` type of `RandomState` is creatively called... `Hasher`! This concrete structure lives next to `RandomState` as an implemenation of the "default hashing algorithm" used for a `HashMap`. Under the hood this is currently implemented as `SipHasher`, but it draws an explicit interface for now and allows us to modify the implementation over time if necessary. There are many breaking changes outlined above, and as a result this commit is a: [breaking-change]		2015-01-07 12:18:08 -08:00
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mk	rollup merge of #20584 : brson/versioning	2015-01-05 18:42:08 -08:00
src	std: Stabilize the std::hash module	2015-01-07 12:18:08 -08:00
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README.md

The Rust Programming Language

This is a compiler for Rust, including standard libraries, tools and documentation.

Quick Start

Download a binary installer for your platform.
Read the guide.
Enjoy!

Note: Windows users can read the detailed using Rust on Windows notes on the wiki.

Building from Source

Make sure you have installed the dependencies:
- g++ 4.7 or clang++ 3.x
- python 2.6 or later (but not 3.x)
- perl 5.0 or later
- GNU make 3.81 or later
- curl
- git
Download and build Rust:

You can either download a tarball or build directly from the repo.

To build from the tarball do:
```
 $ curl -O https://static.rust-lang.org/dist/rust-nightly.tar.gz
 $ tar -xzf rust-nightly.tar.gz
 $ cd rust-nightly
```
Or to build from the repo do:
```
 $ git clone https://github.com/rust-lang/rust.git
 $ cd rust
```
Now that you have Rust's source code, you can configure and build it:
```
 $ ./configure
 $ make && make install
```
Note: You may need to use sudo make install if you do not normally have permission to modify the destination directory. The install locations can be adjusted by passing a --prefix argument to configure. Various other options are also supported, pass --help for more information on them.

When complete, make install will place several programs into /usr/local/bin: rustc, the Rust compiler, and rustdoc, the API-documentation tool.
Read the guide.
Enjoy!

Building on Windows

To easily build on windows we can use MSYS2:

Grab the latest MSYS2 installer and go through the installer.
Now from the MSYS2 terminal we want to install the mingw64 toolchain and the other tools we need.
```
 $ pacman -S mingw-w64-i686-toolchain
 $ pacman -S base-devel
```
With that now start mingw32_shell.bat from where you installed MSYS2 (i.e. C:\msys).
From there just navigate to where you have Rust's source code, configure and build it:
```
 $ ./configure
 $ make && make install
```

Notes

Since the Rust compiler is written in Rust, it must be built by a precompiled "snapshot" version of itself (made in an earlier state of development). As such, source builds require a connection to the Internet, to fetch snapshots, and an OS that can execute the available snapshot binaries.

Snapshot binaries are currently built and tested on several platforms:

Windows (7, 8, Server 2008 R2), x86 and x86-64 (64-bit support added in Rust 0.12.0)
Linux (2.6.18 or later, various distributions), x86 and x86-64
OSX 10.7 (Lion) or greater, x86 and x86-64

You may find that other platforms work, but these are our officially supported build environments that are most likely to work.

Rust currently needs about 1.5 GiB of RAM to build without swapping; if it hits swap, it will take a very long time to build.

There is a lot more documentation in the wiki.

Getting help and getting involved

The Rust community congregates in a few places:

StackOverflow - Get help here.
/r/rust - General discussion.
discuss.rust-lang.org - For development of the Rust language itself.

License

Rust is primarily distributed under the terms of both the MIT license and the Apache License (Version 2.0), with portions covered by various BSD-like licenses.