Changes in Racket 6.6
- The new Macro Profiler command-line tool (`raco macro-profiler`) shows
how macros contribute to the final expanded code size of a program.
- Typed Racket supports intersection types. This allows the type system
to track more information, and for programmers to express more precise
types.
- Typed Racket produces up to 4x smaller compiled files compared with
Racket 6.5, reducing the size of the Racket distribution by 50M.
- Typed Racket issues warnings in cases where the contract generated for
`Any` was not strict enough in the past. These warnings will become
errors in a future release. Warnings are enabled via View -> Show Log
in DrRacket, and shown by default on command-line Racket.
- Typed Racket enforces uses of `cast` more correctly, by checking both
the "casted-to" and "casted-from" types. Previously, only the former
were checked. In some cases, this will produce contract errors in
programs that did not have errors before.
- `syntax-parse` raises an error when an ellipsis pattern has an empty
match rather than diverging, and it logs a warning when it statically
detects a nullable pattern, such as `((~seq) ...)`. In the next version
of Racket, it will reject the pattern instead, and it will remove
special handling that currently makes some uses of such patterns
terminate.
- `htdp/dir`: The `create-dir` function delivers data information for
files in a new field. The domain of its functions are backwards
compatible.
Changes in Racket 6.5
- Typed Racket and the racket/contract library generate code with lower
overhead, speeding up typed/untyped interaction in a number of gradual
typing programs we studied.
- Macros written using `syntax-parse` automatically emit more accurate
error messages.
- The contract profiler captures costs from more contract combinators,
including all those in the main distribution.
- Hash table and set iteration, via both existing and new non-generic
sequences, is more performant, up to twice as fast on microbenchmarks.
- The Racket optimizer detects many more optimization opportunities,
including when variables always hold numbers.
- The `db` library supports multi-result statements in MySQL.
- The `net/dns` library supports SRV records.
- The `racket/unix-socket` library supports listen and accept operations.
Changes in Racket 6.4:
- 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
http://blog.racket-lang.org/2016/02/racket-web-server-security-vulnerability.html
- 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-convertible`s. 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.
Changes in Racket 6.3
- Racket's macro expander uses a new representation of binding called
"set of scopes". The new binding model provides a simpler
explanation of how macros preserve binding, especially across module
boundaries and in hygiene-bending expansions. The new expander is
mostly compatible with existing Racket macros, but there are some
incompatibilities. For the formally inclined, a research paper on
this macro system will appear at POPL next year:
http://www.cs.utah.edu/plt/scope-sets/
- Racket's GUI library now uses Gtk+ 3 when available, instead of Gtk+ 2.
Set the `PLT_GTK2` environment variable to select Gtk+ 2.
- Added a new Redex tutorial based on a week-long workshop in SLC.
- Better syntax error checking for Redex patterns that do not use
holes correctly.
- The blueboxes are more agressive about finding names to look up in
the docs, meaning they are useful much more often.
- Submodules are now fully supported in Typed Racket. Previously, some
uses of submodules would produce internal errors, making it hard to
`module+ test` and `module+ main` effectively in Typed Racket. The
switch to the set-of-scopes expander fixed these problems, and
submodules are now happily at home in Typed Racket.
- The `typed/racket/unsafe` library provides import and export forms
that circumvent contract generation. This improves performance for
typed-untyped interaction at the cost of safety and debuggability.
- Typed Racket provides experimental support for units (from
`racket/unit`).
- The experimental `define-new-subtype` form allows overlaying finer
distinctions between otherwise identical types, similar to Haskell's
`newtype`.
- The `Promise` type constructor changes in a backwards-incompatible
way to exclude promises created with `promise/name`.
- The `unstable-*` packages are out of the main distribution. Most of
their contents have been either merged with established Racket
libraries or spun off as their own packages. This change is
backwards compatible for packages that properly list their
dependencies. Full details:
http://blog.racket-lang.org/2015/10/retiring-unstable.html
- edu: `big-bang` supports a display-mode clause so that world
programs can take over the entire screen.
Changes in Racket 6.2.1
- 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.
Changes:
* 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 Dvorak.
* 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?)
as per upstream changelog:
- Bug repairs and other changes noted in the documentation
- Changed use-before-definition to be an error instead of producing
an #<undefined> value
- Removed the mzlib/class100 library
Also changed the racket port to use mk/jpeg.buildlink3.mk.
Changes in version 6.0.1
* 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.
Changes in version 6.0
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.
* 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 5.3.6
This is a bug-fix release. It eliminates errors from v5.3.5 that
people have found over the summer.
Racket 5.3.5
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 5.3.4
* 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'.
Changes in Racket v5.3.2
Core Libraries:
* The new `math' library provides functions and data structures for
working with numbers and collections of numbers. Functions include
non-elementary (such as gamma, zeta, Lambert's W), number-theoretic
(factorization, modular arithmetic), linear algebra (arithmetic,
decompositions), and statistical (expected values, order statistics,
binning). Data structures include arbitrary-precision bigfloats,
probability distributions, and multidimensional arrays.
* The new `file/untar', `file/untgz', and `file/unzip' libraries support
unpacking widely used archive formats.
* The new `lazy-require' form allows programs to delay the loading and
instantiation of helper modules until they are needed.
* The new `data/bit-vector' library provides an implementation of bit
vectors (a mutable sequence of booleans) supporting popcount.
* The `racket/generic' library allows the specification of default
method implementations for core datatypes.
* The `openssl' library can verify hostnames and use the operating
system's certificate store to verify certificates.
Package System:
* A new package system is in beta release. This system will become
Planet's successor. It differs significantly from the latter. For
details, please read the documentation at
http://docs.racket-lang.org/planet2/ and list your packages on the new
index at https://pkg.racket-lang.org/.
* The `raco test' command supports testing by collection and package, in
addition to by directory and file, with the "-c" and "-p" options.
Teaching Libraries:
* batch-io: the read and write functions work on Unix-style standard
input and output.
DrRacket:
* DrRacket's GUI is more responsive.
* The automatic parenthesis insertion mode is improved.
Scribble:
* Scribble renders Markdown format files via the "--markdown"
command-line flag. Example use case: Generate documentation hosted on
GitHub or BitBucket.
* Documentation cross-reference information is stored in an SQLite3
database, which means that SQLite3 is required for building Racket
documentation on Unix/Linux machines (but SQLite3 is included in
Racket distributions for Windows and Mac OS X).
Using a database for cross-reference information significantly reduces
the initial footprint of DrRacket, since DrRacket no longer needs to
load all cross-reference information.
Typed Racket:
* Typed Racket programs can require `plot/typed' to draw plots. List-
and vector-accepting functions accept general sequences.
* Typed Racket supports Racket's delimited continuation and continuation
mark operators.
Redex:
* Added more support for `define-judgment-form', including random
generation for well-formed judgments and visualization of judgments.
Deprecation:
The following have been removed in this release:
* the `planet' command-line tool; use `raco planet' instead.
The following has been deprecated and will be removed in the August 2013
release:
* the `mzlib/class100' library; use `racket/class' instead.
Changes in Racket v5.3.1
Racket:
* The `case' form dispatches on characters, fixnums, symbols, and
keywords in logarithmic time. (Thanks to Jon Zeppieri.)
* The new `racket/format' library provides new and improved
string-formatting functions.
* Logging tools include improved filtering support based on the name
of a logger. A new `define-logger' form simplifies the use of
named loggers. Forms such as `log-debug' now support string
formatting.
* The `for' forms now support `#:break' and `#:final' clauses.
* The new PLTCOMPILEDROOTS environment variable configures the
search path for compiled bytecode.
DrRacket:
* Check Syntax now summarizes the documentation (i.e., the blue
boxes) for the identifier at the insertion point in the top-right
corner of the definitions window.
* Check Syntax now runs continuously for programs that declare their
language within the source. This mode has been available for
several of the past releases, but now enabled by default.
* DrRacket can spell-check string constants (enable this in the Edit
menu).
Typed Racket:
* Typed Racket interprets the Any type as a different contract.
This may signal dynamic errors in some existing mixed
typed/untyped programs. The normal fix is to replace a use of Any
with a more specific types.
* NaN is included in all of Typed Racket's floating-point types,
which makes precise floating-point types easier to use.
* Typed Racket supports a `cast' operation with support for
higher-order types.
* Typed Racket provides the `:query-type/args' and
`:query-type/result' utilities to explore types at the REPL.
Miscellaneous:
* The `compatibility' collection provides features from Racket
relatives, such as `defmacro' and mutable lists. These features
are provided to ease porting code to Racket. Avoid them in modern
Racket code.
* Screenshots of the widgets provided by the Racket GUI library are
included in the documentation. (Thanks to Diogo F. S. Ramos.)
* FrTime was ported to racket lang. (Thanks to Patrick Mahoney.)
Deprecation:
The following has been deprecated and will be removed in the January
2013 release:
* the `planet' command-line tool; use `raco planet' instead.
The following has been deprecated and will be removed in the August
2013 release:
* the `mzlib/class100' library; use `racket/class' instead.
Changes in Racket 5.3
* Submodules are nested module declarations that can be loaded and
run independently from the enclosing module. For an overview of
submodules, see
http://blog.racket-lang.org/2012/06/submodules.html
* The futures visualizer is a graphical profiling tool for parallel
programs using futures. The tool shows a detailed execution
timeline depicting the migration of futures between threads, and
gives detailed information about each runtime synchronization that
occurred during program execution. In addition, `would-be-future'
is a special type of future that always executes sequentially and
records all potential barricades a regular future would encounter.
* Optimization Coach (formerly Performance Report) reports
information about Racket's inlining optimizations. Optimization
Coach can be launched in any language through the View menu.
* The new `images/flomap' library defines floating-point bitmaps and
fast image processing operations on them. It is written in Typed
Racket, so Typed Racket code may use it without the cost of
contract checks.
* The new `json' library supports parsing and generating JSON.
(Originally based on Dave Herman's planet library.)
* `racket/string' is extended with a set of simplified string
manipulation functions that are more convenient than using
regexps. `regexp-match*' and friends can now be used with new
keyword arguments to return specific matched regexp group/s and
gaps between matches.
* The new `racket/generic' library allows generic function
definitions, which dispatch to methods added to a structure type
via the new `#:methods' keyword.
* The `class' form supports declaring a method abstract. An
abstract method prevents a class from being instantiated unless it
is overridden.
* The contract library comes with support for interfaces, generics,
prompts, continuation-marks, and structs.
* Most error messages use a new multi-line format that is more
consistent with contract errors and accommodates more information.
* Typed Racket supports function definitions with keyword arguments;
the startup time of Typed Racket programs has been sharply
reduced.
* The new `ffi/com' library replaces MysterX; a compatibility
`mysterx' library remains, but without ActiveX support. The new
`ffi/unsafe/com' library offers a more primitive and direct way to
use COM classes and methods.
* There is now a very complete completion code for zsh. It is not
included in the distribution though; get it at http://goo.gl/DU8JK
(This script and the bash completions will be included in the
standard installers in future versions.)
--- DEPRECATION ----------------------------------------------------
Effective this release:
- The `tex2page' and `combinator-parser' libraries have been moved
from the Racket distribution to PLaneT:
(require (planet plt/tex2page))
(require (planet plt/combinator-parser))
The following has been deprecated and will be removed in the
January 2013 release:
- the `planet' command-line tool; use `raco planet' instead.
The following has been deprecated and will be removed in the
August 2013 release:
- the `mzlib/class100' library; use `racket/class' instead.
Changes in Racket 5.2.1
* Performance improvements include the use of epoll()/kqueue()
instead of select() for the Racket thread scheduler, cross-module
inlining of small functions, and the use of SSE instead of x87 for
JIT-compiled floating-point operations on platforms where SSE is
always available (including x86_64 platforms). A related change
is the interning of literal numbers, strings, byte strings,
characters, and regexps that appear in code and syntax objects.
* DrRacket uses a set of composable ray-traced icons available from
the new `images' library collection.
* Typed Racket's `typecheck-fail' form allows macro creators to
customize the error messages that Typed Racket produces. This is
especially useful when creating pattern matching macros.
* The performance of Redex's matcher has been substantially
improved; depending on the model you should see improvements
between 2x and 50x in the time it takes to reduce terms.
* Plots look nicer and are more correct at very small and very large
scales. New features include customizable dual axis ticks and
transforms (e.g., log axes, date and currency ticks, axis interval
collapse and stretch), stacked histograms, and 3D vector fields.
The legacy `fit' function and libfit have been removed.
* The `2htdp/universe' library's `big-bang' form supports an
experimental game pad key handler.
* The `db' library now supports nested transactions and PostgreSQL
arrays. Bugs involving MySQL authentication and memory corruption
in the SQLite bindings have been fixed.
* The Macro Stepper tool in DrRacket no longer executes a program
after expanding it.
* In the DMdA teaching languages, infinite recursive signatures
("streams", for example) with no intervening `mixed' are now
supported, and the signatures of record definitions without fields
now have generators for use with `property'.
* MysterX's ActiveX support is deprecated and will be removed in the
next release. MysterX's core COM functionality will become
deprecated in the next release, but COM functionality will be
supported for the foreseeable future as a compatibility layer over
a forthcoming `ffi/com' library.
Release Highlights:
* DrRacket comes with an experimental, on-line check syntax tool,
although this new tool is disabled default. See below for more
information.
* The new `db' library offers a high-level, functional interface to
popular relational database systems, including PostgreSQL, MySQL,
and SQLite, as well as other systems via ODBC.
* A new XREPL collection provides convenient commands for a plain
racket REPL. It is particularly convenient for people who prefer
console-based work and alternative editors. See also the new
chapter on command-line tools and other editors at the end of the
Racket Guide.
* The `plot' collection has been reimplemented in Racket. It now
offers PDF output, log axes, histograms, and more. Some code that
uses `plot' will still work, and some will need light porting.
The `plot/compat' module offers expedient backward compatibility.
* DrRacket uses more conventional key bindings: `C-t' creates a new
tab, `C-w' closes the current one, and `C-r' runs the definitions.
On Mac OS X, the Command key is used. See "Defining Custom
Shortcuts" in the DrRacket manual for an example that uses the old
key bindings.
* The new `raco link' command registers a directory as a collection,
which allows the collection directory to reside outside the
"collects" tree and without changing the PLTCOLLECTS environment
variable.
* Typed Racket:
- Typed Racket provides static performance debugging support to
show which code gets optimized and point out code that does not.
Use the "Performance Report" button in DrRacket.
- More intuitive types in printouts in the REPL and in error
messages. Use `:query-result-type' to explore types, or
`:print-type' for a full printout.
- Typed Racket now supports defining function with optional
arguments using the same syntax as Racket.
* Redex now supports specifying (and testing and automatically
typesetting) judgment forms including type systems and SOS-style
operational semantics.
* Fixed several GUI problems, including problems on Ubuntu 11.10
(GTK+ 3) and 64-bit Mac OS X.
* Internal-definition expansion has changed to use `let*' semantics
for sequences that contain no back references. This change
removes a performance penalty for using internal definitions
instead of `let' in common cases, and it only changes the meaning
of programs that capture continuations in internal definitions.
Internal definitions are now considered preferable in style to
`let'.
* Support for `begin-for-syntax' has been generalized; modules may
now define and export both value bindings and syntax bindings
(macros) at phase 1 and higher.
Due to a bug, phase 1 syntax (or higher) is not available in
DrRacket's `#lang'-based REPL. A simple workaround is to disable
debugging in DrRacket (see "no debugging" radio button in detailed
language dialog).
Additional Items:
* The `racket/gui' library (and Slideshow) provides more support for
multiple-screen displays.
* DrRacket remembers whether an opened file used LF or CRLF line
endings, and will continue using the same. When creating a new
file, a preference determines how it is saved.
* `net/url' can now follow HTTP redirections.
* The LNCS and JFP class files are no longer distributed with
Racket. Instead, they are downloaded on demand.
* The Algol language implementation is now available as a plain
language using `#lang algol60'.
* The Racket-to-C compiler (as accessed via `raco ctool' or `mzc')
has been removed; Racket's JIT has long provided better
performance, and the FFI provides better access to C libraries.
* Contracts can be applied to exports with the new `contract-out'
form within `provide', instead of a separate `provide/contract'
form. (The new `contract-out' form is implemented as a new kind
of "provide pre-transformer".)
* The `date*' structure type is an extension of `date' with
`nanosecond' and `time-zone-name' fields.
* New looping constructs: `for/sum' and `for/product'.
* Direct calls to keyword-accepting functions are now optimized to
eliminate the overhead of keywords. In addition, the compiler
detects and logs warnings for keyword-argument mismatches.
* The libfit interface is available from `plot/deprecated/fit', and
will be removed in the near future.
* The Unix installer has been re-done, and it is now more robust.
* The built-in reader and printer support for Honu is removed.
(This functionality is re-implemented in Racket.)
On-line Check Syntax:
DrRacket now provides an on-line version of the syntax check tool,
which means that syntax checking runs automatically while you
continue to edit a program. With this tool enabled, its annotations
(e.g., binding arrows) and actions (e.g., the renaming refactoring
and direct documentation links) are almost always available.
We have noticed that on-line syntax checking renders DrRacket
unstable on occasion, perhaps because it relies on relatively new
support for parallelism. Occurrences of the problem are rare, but
they are not rare enough, which is why we have disabled the tool by
default. At the same time, current users of the tool find it so
valuable that we felt it should be included in the release. We
expect to track down the remaining problems and enable the tool by
default in near-future release.
To enable on-line syntax checking (for `#lang'-based programs only),
click on the red dot in the bottom right of DrRacket's window. To
turn it off, click there again.
Changes in Racket 5.1.3
This is a bugfix release, resolving the DrRacket issue with
the contour view. In addition, two tex files with problematic
licensing were removed.
Changes in Racket 5.1.2
* The download page includes 64-bit installers for Mac OS X,
Windows, and two Debian flavors. Racket now supports OS X Lion.
* Racket now includes a new `racket/place' library to support
parallelism, complementing `racket/future'. Racket's parallel
build process is now based on places instead of multiple OS
processes.
Places support share-nothing parallelism and message-passing
communication. Compared to futures, places are heavyweight, but
they have a simpler performance model.
* The syntax-certificate system has been replaced by a syntax-taint
system. Both certificates and taints were designed to protect
otherwise inaccessible bindings from abuse when they appear in
macro expansions. Taints are simpler and lighter, and the switch
closes known holes in the certificate system. Macros that are not
implemented with `syntax-rules' or `define-syntax-rule', however,
must explicitly use `syntax-protect' to protect their expansions
from abuse.
* The `net/url' library supports HTTPS connections, but beware that
by default all sites are accepted (equivalent to ignoring a
browser's warnings about untrusted certificates).
* Error messages in the student languages use a simplified
vocabulary and consistent phrasings. If you maintain curriculum
material or teachpacks then please consider updating. See the
"Error Message Composition Guidelines" section in the
documentation for details.
* Typed Racket: almost all core Racket data structures and
operations are now accessible in Typed Racket (most of this work
is due to prolific contributor Eric Dobson). The performance of
the typechecker has been significantly improved.
* The `scriblib/bibtex' library supports BibTeX-formatted citation
databases in Scribble documents. BibTeX can be tricky to parse,
so please report failed entries as bug reports.
* The `for' forms now support an `#:unless' clause, and a
nonnegative integer can be used as a sequence. The new `compose1'
function creates single-valued composition functions. The
`racket/function' library now provides `identity', `thunk', and
`thunk*'.
* The license has been clarified: we now use LGPLv2.1 uniformly.
(The license file used to specify LGPLv2, contrary to the download
pages.)
Changes in version 5.1.1, May 2011:
Enabled single-precision floats by default
Added single-flonum?
Changed eqv? so that inexacts are equivalent only when they
have the same precision
Changed file-or-directory-permission to add 'bits mode
and permission-setting mode
Added special treatment of void as an 'inferred-name property
Removed the "MrEd" compatability executable under Windows
and Mac OS X, but the "mred" compatibility script remains
racket/gui: added multi-column support to list-box%
racket/gui: added scrollbar support to panel%, vertical-panel%,
and horizontal-panel%
racket/gui: added 'wheel-left and 'wheel-right events
racket/file: add user-read-bit, etc.
racket/contract: removed some (undocumented) exports.
Changes in version 5.1, February 2011
Renamed "proxy" to "impersonator"
Added current-get-interaction-input-port, which enables
racket/gui events to be dispatched while a REPL is blocked
Changed equal? to equate C pointers when they refer to the
same address
Internal: weak boxes are cleared before non-will-like
finalizers; use late-weak boxes to get the old behavior
Changes in version 5.0.2, October 2010
Changed body of `when', `unless', `cond' clauses, `case'
clauses, and `match' clauses to be internal-definition contexts
Swapped unsafe-vector*-ref with unsafe-vector-ref, etc.
Added ->i to the contract library, improved ->*, adding #:pre and
#:post, as well as making the optional arguments clause optional.
Added #true and #false, and changed #t/#T and #f/#F to
require a delimiter afterward
Added print-boolean-long-form
Added read-accept-lang, which is set to #t when
reading a module
Added flonum?
Changed continuation-marks to accept a #f argument
to produce an empty set of marks
Added fxvectors
Added unsafe-{s,u}16-{ref,set!}
Added prop:proxy-of
Added proxies to go with chaperones, and renamed chaperone property
as proxy property; beware that the word "proxy" will change in
a future version, perhaps to "impersonator"
Added collection-file-path and collection splicing at the file
level
Continuation barriers now block only downward continuation jumps
and allow escapes through full continuations
Changed internal-definition handling to allow expressions mixed
with definitions
Added support for subprocesses as new process groups
Added support for best-effort termination of subprocess by a
custodian
Added flreal-part, flimag-part, make-flrectangular, and unsafe
variants
Added fl->eact-integer, fl->fx, and unsafe-fl->fx
Added #:async-apply option to _fun
Added chaperone-evt
Added identifier-prune-to-source-module
Changed apply binding to enable lower-level optimizations
Upgraded to libffi 3.0.9+
Import textual Racket version as lang/racket-textual.
Racket (formerly PLT Scheme) is a specific dialect of the Lisp
language based on the Scheme branch of the Lisp family.
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