• Oct 26, 2016
  • Jul 22, 2016
  • Apr 22, 2016
  • Feb 8, 2016
  • Nov 19, 2015
  • Aug 10, 2015


    Racket 6.2.1
    Version 6.2.1 patches the recent v6.2 release in three small ways:
    * For the How to Design Programs teaching languages, DrRacket offers
      an option to use the old style for printing the constants `true`,
      `false`, and `empty` instead of `#true`, `#false`, and `'()`.
    * The teaching languages come with some additional functions to match
      the August 2015 stable release of HtDP 2nd edition.
    * A repair to the compiler avoids an infinite loop at compile time for
      certain expressions that should loop forever at run time.
  • Jul 16, 2015


    Merge git.racket-lang.org:plt
  • Jun 19, 2015


    Racket v6.2
    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.
    * 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.
    * Added data/enumerate, a library that supports efficient enumeration of
      data structures
    * 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`.
  • Nov 4, 2014


    Racket v6.1.1
    * The MAC OS X YOSEMITE compatibility problems are fixed. We
      bundled a patched Pango text-drawing library with Racket.
    * The WINDOWS [32-bit] releases fixes the window-update crashes.
      We bundled a patched Cairo drawing library with Racket.
    * TYPED RACKET closes two safety holes in the exception system.
      The revised type system restricts `raise' to send only
      instances of the `exn' structure type and flat data to
      handlers. It also checks exception handlers properly.
      NOTE: Previously well-typed programs may fail to typecheck.
    * TYPED RACKET'S typed regions support casts and predicates.
    * 2HTDP/IMAGE'S notion of equality ignores an image's baseline.
    * The PACKAGE MANAGER supports a binary library installation mode,
      which allows users to install packages without source or documentation.
      Use the `--binary-lib' option with `raco pkg install'.
    * The new DRRACKET-TOOL-LIB package factors out parts of DrRacket's
      IDE so that they can be reused with other editors, such as Emacs.
    * The COMPILER'S use-before-defined analysis has been repaired for
      certain forms of nested `letrec', some `let' forms, and some
      uses of `set!' or `with-continuation-mark'.
    * The COMPILER performs additional bytecode optimizations.
      Thanks to Gustavo Massaccesi.
    * The CML library comes with a new `replace-evt' event constructor.
      Thanks to Jan Dvořák.
    * REDEX'S benchmark suite comes with a description of the benchmark
    * REDEX'S metafunctions can be typeset using the "large left brace"
      notation for conditionals.
    * The CONTRACT library comes with an improved `contract-stronger?'.
      Its error messages note that the contract itself might be wrong.
    * The GUI library is DPI-aware on Windows.
    * The OPENSSL library supports Server Name Indication for servers.
      Thanks to Jay Kominek.
    * The SYNTAX/PARSE library allows the definition of new pattern
      forms via pattern expanders, similar to match expanders.
      Thanks to Alex Knauth.
    * OpenGL on Linux no longer depends on libgtkgl, and core profiles
      are supported (see `set-legacy?').
    * The TEACHING LANGUAGES' unit test framework supports
      `check-satisfied', a construct for checking whether a result
      satisfies a predicate, e.g.: (check-satisfied (sort l) sorted?)
  • Aug 2, 2014


    Racket v6.1
    The MAJOR INNOVATION concerns local recursive variable definitions.
    Instead of initializing variables with an `undefined' value, Racket
    raises an exception when such a variable is used before its definition.
    (Thanks to Claire Alvis for adapting Dybvig's "Fixing Letrec" work.)
    Since programs are rarely intended to produce #<undefined>, raising an
    exception provides early and improved feedback. Module-level variables
    have always triggered such an exception when used too early, and this
    change finally gives local bindings --- including class fields --- the
    same meaning.
    This change is backwards-incompatible with prior releases of Racket.
    Aside from exposing a few bugs, the change will mainly affect programs
    that include
    (define undefined (letrec ([x x]) x))
    to obtain the #<undefined> value. In its stead, Racket provides the same
    value via the `racket/undefined' library (which was introduced in the
    previous release). Programmers are encouraged to use it in place of the
    pattern above to obtain the "undefined" value.
    The release also includes the following SMALL CHANGES:
    * PLUMBERS generalize the flush-on-exit capability of primitive output
      ports to enable arbitrary flushing actions and to give programmers
      control over the timing of flushes (i.e., a composable `atexit').  New
      functions include `current-plumber', `plumber-add-flush!', and
    * CONTRACTS: the contract system's random testing facility has been
      strengthened so that it can easily find simple mistakes in contracted
      data structure implementations (e.g. an accidental reverse of a
      conditional in a heap invariant check).
    * REDEX: the semantics of mis-match patterns (variables followed by _!_)
      inside ellipses has changed in a backwards-incompatible way. This
      change simplifies the patterns' semantics and increases the usefulness
      of these patterns.
    * TEACHING LANGUAGES: `check-random' is an addition to the preferred
      unit testing framework in the teaching languages. It enables the
      testing of students' functions that use random-number
      generation. (Thanks to David Van Horn (UMaryland) for proposing this
    * Upgraded and normalized versions of GRAPHICS LIBRARIES and
      dependencies (Pango, Cairo, GLib, etc.) that are bundled with Racket
      on Windows and Mac OS X. For example, FreeType support is consistently
    * TYPED RACKET: its standard library includes contracted exports from
      the Racket standard library, such as the formatting combinators of
      `racket/format'. It also supports Racket's asynchronous channels; see
      the `typed/racket/async-channel' library.
    * SSL: The openssl library supports forward secrecy via DHE and ECDHE
      cipher suites (thanks to Edward Lee) and Server Name Indication
      (thanks to Jay Kominek).
    * The `mzlib/class100' library has been REMOVED. Use `racket/class'