Hello and welcome to another issue of This Week in Rust! Rust is a systems language pursuing the trifecta: safe, concurrent, and fast. This is a weekly summary of its progress and community. Want something mentioned? Send me an email! Want to get involved? We love contributions.

What's cooking on master?

76 pull requests were merged this week.

Breaking Changes

• A significant amount of functionality has moved from libstd to a new libcore crate, which is intended to be usable in a freestanding environment (it doesn't use any allocation etc). See the pull request for further details.
• All mentions of ~ outside of ~str and ~[] have been removed from the language.
• ~[T] no longer implements FromIterator, and many APIs have been updated to use Vec.
• The local_data API has been modernized to use methods on keys, RAII, and removal of essentially unused features.
• Trait inheritence with incorrect use of lifetimes has been fixed. See the second commit for a testcase and explanation.
• Cross-crate enum variant privacy has been fixed. Previously, private variants were always usable without restriction.
• Format string parsing has been moved outside of std.
• The bump_box_refcount function has been removed.
• unsafe extern fn definitions are now allowed, with a corresponding change in how that type is written (previously the parser accepted extern unsafe fn()).
• bitflags! now allows setting attributes on the generated type, and FilePermissions has been ported to it.

Other Changes

• Box<T> is the new syntax for ~T.
• Sockets now have non-blocking IO!
• TcpStream and UnixStream have methods to cancel reads/writes.
• There is now limited support for mixing rlibs and dylibs when linking to dependencies.
• The stats crate has been generalized to the Float trait.
• A graphviz crate has been added for generating dot files.
• Some missing cases in the type_limits lint have been fixed.
• box has been added to the pattern grammar.
• An injection bug in rustdoc's web frontend has been fixed.
• Use of non-existent method which has the same name as an existing static method now has a note attached.

New Contributors

• Aaron Raimist
• Ali Smesseim
• Dirk Leifeld
• James Laverack
• Lucas Dohmen
• Phil Ruffwind
• Tim Brooks

Weekly Meeting

The weekly meeting discussed many things. I think I'm going to stop including this section of TWiR because the meeting notes are very well-kept (thanks Lars!) and there's often too much to effectively summarize.

RFCs

• Remove *mut T, add *const T
• Add byte and byte string literals
• Allow blocks in constants
• Algebraic effect system
• Split Iterator into Iterator and FiniteIterator

Community Updates

• Bay Area Rust, May 2014: Testing
• New meetup at Pittsburgh Code and Supply
• Rust for C++ programmers - part 5: borrowed references
• Header compression library for HTTP/2
• rust-graphics, how Rust's type system might improve graphics programming
• Informal survey: Which is clearer, mutability or uniqueness?
• Teepee design: header representation
• How to test Rust on travis-ci