With this release we are taking a major step forward to get our user
community even more involved than in the past. Over the past six months,
we have re-organized the Racket code base into a small core code repo
and many other package repos, all found on GitHub. If you have time and
if you wish to get involved, please take a look at the GitHub repos and
find your favorite places to learn, fix, and enhance our world.
The core repo is at https://github.com/plt/racket, and the
package repos are listed at https://github.com/racket/.
* The package manager supports a direct references to Git repositories
via "git://[...]", "http://[...].git", and "https://[...].git" URLs.
(Previously, only references to GitHub were supported.)
* A `--clone` option for `raco pkg install` or `raco pkg update`
facilitates Git-based package development. If a package X has a Git
repository source, installing and updating the package pulls from the
repository in a read-only mode. Using `raco pkg update --clone X`
switches the local installation to a repository checkout that is
suitable for modifying the package implementation, issuing pull
requests, pushing changes, and so on.
Using `raco pkg update --lookup X` switches the package back to the
default installation mode.
* Its on-line check syntax works with graphical content.
* Increased availability of DrRacket's blueboxes, including method and
* The "Open Require Path" menu item supports ".." in relative pathnames.
* Added data/enumerate, a library that supports efficient enumeration of
* Its redex-check facility uses data (in addition to random) enumeration
to try to find counter-examples.
* Its generate-term function accepts additional arguments to return the
"i"-th member of a pattern using data/enumerate (meaning it
efficiently supports very large values of "i").
* The examples collection includes Launchbury's 1993 big-step lazy semantics.
* 2htdp/image's polygon may be built out of bezier curves instead of
just straight lines (see the docs for "pulled-point").
* 2htdp/abstraction is a teachpack for instructors and students who wish
to use for/* loops, match, define-type and type-cases in ISL and ISL+.
* 2htdp/universe programs can be exported using DrRacket's executable
creation mechanism and they behave properly when run independently.
* Typed Racket in DrRacket displays tooltips that show the types of
expressions. Tooltips are also displayed for type errors.
* Typed Racket loads generated contracts only when needed. This reduces
memory use and startup time for Typed Racket programs.
* Typed Racket has improved support for prefab structures, future
semaphores, and async channels.
* Typed Racket understands when two different variables refer to the
same thing, and updates types accordingly. This particularly improves
the type checking of macros such as `match`.