extra library -> standard library
* [sprocketnes], an NES emulator with no GC, using modern Rust conventions
* The language's general-purpose [hash] function, SipHash-2-4. Bit twiddling, OO, macros
* The standard library's [HashMap], a sendable hash map in an OO style
-* The extra library's [json] module. Enums and pattern matching
+* The standard library's [json] module. Enums and pattern matching
[sprocketnes]: https://github.com/pcwalton/sprocketnes
[hash]: https://github.com/rust-lang/rust/blob/master/src/libstd/hash/mod.rs