Racket version 6.4 is now available from http://racket-lang.org/
- We fixed a security vulnerability in the web server. The existing web server is vulnerable to a navigation attack if it is also enabled to serve files statically; that is, any file readable by the web server is accessible remotely. For more information, see this post.
- DrRacket's scrolling is faster.
- Incremental garbage-collection mode can eliminate long pauses in a program. For example, incremental mode is useful for avoiding pauses in games and animations.
Programs must specifically request incremental mode with (collect-garbage 'incremental), but libraries such as 2htdp/universe include the request as part of the library's implementation.
- The default package catalog is an HTTPS address instead of HTTP, and package operations properly validate server certificates when using HTTPS.
- Documentation may define their own categories for the manual top-level page by using strings, rather than only symbols that name pre-defined categories.
- The Racket cheat sheet is included in the main distribution.
- DrRacket is available in Bulgarian, thanks to Alexander Shopov.
- The contract Typed Racket generates for the Any type is more permissive, allowing more typed/untyped programs to work without contract errors.
- Redex supports binding specifications; describe which variables bind in which expressions and your metafunctions and reduction relations automatically become scope-sensitive. Thanks to Paul Stansifer for this improvement.
- All pict functions accept pict-convertibles. This allows for transparent interoperability between pict and libraries like 2htdp/image.
- The raco profile and raco contract-profile commands provide easy access to profiling tools, without requiring program modifications.