Racket v6.2

Racket version 6.2 is now available from http://racket-lang.org/

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/.

core repo

• 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.

drracket

• Its on-line check syntax works with graphical content.
• Increased availability of DrRacket's blueboxes, including method and constructor information.
• The "Open Require Path" menu item supports ".." in relative pathnames.

data

• Added data/enumerate, a library that supports efficient enumeration of data structures

redex

• 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.

htdp

• 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

• 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.

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