Release notes from racket

Racket v6.1.1

2014-11-04T14:52:36Z

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
programs.
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?)

Racket v6.1

2014-08-02T17:51:28Z

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 #, 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 # 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 plumber-flush-all'.
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
idea.)
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
enabled.
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'
instead.

Racket v6.0.1

2014-05-08T20:13:40Z

A new racket/undefined library exports undefined as the value
currently produced by

(letrec ([x x]) x)

This library anticipates a future where that expression will raise
an exception. The racket/undefined library will continue to offer
the undefined value as a bridge between versions and as a last
resort.
The drawing and GUI libraries provide improved support for
high-resolution bitmaps and their use on Retina displays. For
example, read-bitmap includes a #:try-@2x? option to trigger
substitutions through the usual "@2x" naming convention.
Check Syntax cooperates with Typed Racket to show arrows and other
Check Syntax highlighting even when there is a type error.
Functions provided via contract-out that have first-order contracts
perform better.
The contract boundary between typed/untyped modules is much less
expensive. Typed Racket now avoids generating contracts for places
where contracts failures cannot happen.
Occurrence typing now works better with when/unless. Example:

(let ((x (read)))
(unless (number? x) (error 'bad-input))
(add1 x))
Types in Typed Racket are now pretty-printed.
Function types can now be written in prefix style, which is now
preferred and is used for printing. Infix function types are still
accepted for backwards compatibility.
A new `->*' type constructor is used for writing types for functions
with optional and keyword arguments. The notation is similar to the
matching contract combinator.
Typed Racket forms do not have a :' suffix by default now. For example, the struct' form replaces `struct:'. The suffixed versions
are all provided for backwards compatibility.
Typed Racket now has preliminary support for classes and
objects. However, it is still experimental and the APIs are subject
to change.
Type aliases in Typed Racket now support recursion and mutual
recursion. For example, `(define-type (MyList X) (U Null (Pair X
(MyList X))))' is now a valid type alias.
Plot correctly renders intersecting 3D graphs and non-grid-aligned
3D rectangles.
Elements in plots output in PDF/PS format have the same relative
scale as in other formats. In particular, it is not necessary to
adjust plot-font-size to make PDF plots look the same as PNG.

Racket v6.0

2014-02-26T22:18:28Z

Racket 6.0 has a new package system, including a catalog of
hundreds of already-available packages. Please visit

http://pkgs.racket-lang.org/

for an overview of the packages.

Racket versions 5.3.4 through 5.3.6 included "beta" versions of the
package system. Racket version 6.0 incorporates many improvements
suggested by preliminary experiences in those versions:

A package is treated as a single collection by default, so it is
even easier to use a GitHub repository as a package. Get started
quickly:
http://docs.racket-lang.org/pkg/getting-started.html
DrRacket includes a new package manager GUI, available via the
File|Package Manager ... menu item. The GUI is also available
as a stand-alone program via the "gui-pkg-manager" package.
The main Racket distribution has been separated into about 200
packages. The Racket installer combines the core system with
bundled versions of these packages.

Alternatively, you may now install a Minimal Racket distribution
--- which is about 1/10 the size of the main distribution --- and
add only those packages that you need.
Package installation supports pre-built packages that include
compiled byte code and rendered documentation, meaning packages can
be installed quickly when built versions are available. All
packages in the main distribution are available in pre-built form.

The recent 5.92 and 5.93 releases served as release candidates for 6.0,
and 6.0 includes a few additional repairs related to the package
system.

Further improvements to the package system are in the works, notably
including package documentation on the package-catalog web site.

COMPATIBILITY NOTE: PLaneT, the previous Racket package system, will
remain in place for the foreseeable future, but we expect all package
work to shift to the new system.

Beyond the package system, this release brings a number of other
changes:

Racket's HTML documentation has a new and improved look, thanks to
Matthew Butterick.
The documentation includes a style guide, "How to Program Racket"
http://docs.racket-lang.org/style/
Racket's JIT compiler supports the ARM architecture.
Racket supports the Mac's Retina display mode.
The performance of the Typed Racket compiler improved by 50% on
some typed programs; e.g., see http://bit.ly/1d0Ye4z
The profiler provides a new mode that uses the errortrace library
to produce fine-grained profiles.
A new contract profiler reports how much time programs spend
checking contracts, and which contracts are most expensive.
The math/flonum library exports fast 105-bit precision operations.
Check Syntax handles generated identifiers, especially those
introduced by struct (e.g. field selectors) and Redex (e.g., e_1,
e_2)
2htdp/batch-io includes functions for dealing with html/xml in
files and web sites as X-expressions plus conveniences for
web-based graph traversals.
The `gen:set' generic interface extends set operations to work on
user-defined types that implement set methods, as well as on other
set-like built-in types, such as lists.
Picts support conversion to SVG format.
Under unix, Racket provides desktop entries (.desktop files) for
its graphical executables.

Racket v5.93

2014-01-31T23:23:45Z

Version 5.93 repairs a few problems with the recent v5.92 release (in
preparation for a v6.0 release):

fixed a low-level concurrency problem with the GUI library for Mac
OS X, which especially affected 32-bit builds;
fixed GRacket-based launchers (such as drracket) in a Unix-style
installation;
expanded the list of recognized OpenSSL library versions;
fixed small CSS problems and inconsistencies (relative to v5.3.6) in
the new Scribble style as used by the Racket documentation; and
added the version number back to the "racket" directory within the
source distribution bundle.

Racket v5.92

2014-01-25T16:56:08Z

Racket 5.92 has a new package system, including a catalog of
hundreds of already-available packages. Please visit

http://pkgs.racket-lang.org/

for an overview of the packages.

Recent releases included the "beta" versions of the package system.
Racket version 5.92 incorporates many improvements suggested by these
preliminary experiences:

A package is treated as a single collection by default, so it is
even easier to use a Github repository as a package. Get started
quickly:
http://docs.racket-lang.org/pkg/getting-started.html
DrRacket includes a new package manager GUI, available via the
File|Package Manager ... menu item. The GUI is also available
as a stand-alone program via the "gui-pkg-manager" package.
The main Racket distribution has been separated into about 200
packages. The Racket installer combines the core system with
bundled versions of these packages.

Alternatively, you may now install a Minimal Racket distribution
--- which is about 1/10 the size of the main distribution --- and
add only those packages that you need.
Package installation supports pre-built packages that include
compiled byte code and rendered documentation, meaning packages can
be installed quickly when built versions are available. All
packages in the main distribution are available in pre-built form.

Further improvements are in the works, notably including package
documentation on the package-catalog web site.

COMPATIBILITY NOTE: PLaneT, the previous Racket package system, will
remain in place for the foreseeable future, but we expect all package
work to shift to the new system.

Beyond the package system, this release brings a number of other
changes:

Racket's HTML documentation has a new and improved look, thanks to
Matthew Butterick.
The documentation includes a style guide, "How to Program Racket"
http://docs.racket-lang.org/style/
Racket's JIT compiler supports the ARM architecture.
Racket supports the Mac's Retina display mode.
The performance of the Typed Racket compiler improved by 50% on
some typed programs; e.g., see http://bit.ly/1d0Ye4z
The profiler provides a new mode that uses the errortrace library
to produce fine-grained profiles.
A new contract profiler reports how much time programs spend
checking contracts, and which contracts are most expensive.
The math/flonum library exports fast 105-bit precision operations.
Check Syntax handles generated identifiers, especially those
introduced by struct (e.g. field selectors) and Redex (e.g., e_1,
e_2)
2htdp/batch-io includes functions for dealing with html/xml in
files and web sites as X-expressions plus conveniences for
web-based graph traversals.
The `gen:set' generic interface extends set operations to work on
user-defined types that implement set methods, as well as on other
set-like built-in types, such as lists.
Picts support conversion to SVG format.
Under unix, Racket provides desktop entries (.desktop files) for
its graphical executables.

Racket v5.3.6

2013-08-10T12:47:15Z

Racket v5.3.6 is a bug-fix release. It eliminates errors from v5.3.5
that people have found over the summer.

Racket v5.3.5

2013-06-18T11:00:31Z

This is a special-purpose release to match the arrival of "Realm of
Racket" in bookstores. Racket v.5.3.5 adds a single `realm'
collection to the v5.3.4 release. The new collection contains the
source code that readers of Realm may wish to use for experiments.

Racket v5.3.4

2013-05-08T16:21:58Z

Extflonums (80-bit floating-point numbers) are supported on some
x86/x86_64 platforms -- including Windows, and including platforms
where Racket is compiled to use SSE instructions for flonum
arithmetic. Thanks to Michael Filonenko.
OS X: DrRacket and all of the other apps are now signed with an
official key.
Tally Maze: a new game based an enumeration of 2d mazes.
The Optimization Coach, a DrRacket plugin, has been moved from the
Racket distribution to the Racket package repository. Install it
with: raco pkg install optimization-coach
Redex: `define-union-language' now merges productions when
languages define the same nonterminals. Thanks to William Bowman.
The srfi/19' library is now compatible with the date structure type exported by racket/base'.

Racket v5.3.3

2013-02-15T20:38:09Z

This is a bug-fix release to address a flaw in DrRacket v5.3.2
concerning interactions between the contour window and the syntax
coloring.