[Racket announcement] Racket v6.5

From: Ryan Culpepper (ryanc at ccs.neu.edu)
Date: Thu Apr 28 15:58:00 EDT 2016		 
Racket version 6.5 is now available from

     http://racket-lang.org/

- Typed Racket and the `racket/contract` library generate code with lower
   overhead, speeding up typed/untyped interaction in a number of gradual
   typing programs we studied.

- Macros written using `syntax-parse` automatically emit more accurate
   error messages.

- The contract profiler captures costs from more contract combinators,
   including all those in the main distribution.

- Hash table and set iteration, via both existing and new non-generic
   sequences, is more performant, up to twice as fast on microbenchmarks.

- The Racket optimizer detects many more optimization opportunities,
   including when variables always hold numbers.

- The `db` library supports single-result CALL statements in MySQL.

- The `net/dns` library supports SRV records.

- The `racket/unix-socket` library supports listen and accept operations.

The following people contributed to this release:
Adrien Tateno, Alex Knauth, Alexander Shopov, Alexis King, Andrew Kent,
Asumu Takikawa, Ben Greenman, Chen Xiao, Chris Jester-Young, Daniel
Feltey, Eric Dobson, Georges Dupéron, Gustavo Massaccesi, Ian Harris,
Jay McCarthy, Jens Axel Søgaard, John Clements, Leandro Facchinetti,
Lehi Toskin, Leif Andersen, Łukasz Dąbek, Marc Kaufmann, Matthew Flatt,
Matthias Felleisen, Michael McConville, Mike Sperber, Paul Stansifer,
Philippe Meunier, Robby Findler, Rodrigo Setti, Ryan Culpepper, Sam
Caldwell, Sam Tobin-Hochstadt, Sorawee Porncharoenwase, Spencer
Florence, Stephen Chang, Tony Garnock-Jones, Vincent St-Amour, WarGrey
Gyoudmon Ju, and William J. Bowman.

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