Racket v5.0.1
* Datalog is a lightweight deductive database system with Racket
integration. It is now available in the `datalog' collection and
with `#lang datalog'.
* Racklog provides Prolog-style logic programming in Racket, adapted
from Dorai Sitaram's Schelog package. It is available in the
`racklog' collection and now as `#lang racklog'.
* By default `make install' and `raco setup' compile collections in
parallel on all available processors. (Use `raco setup -j 1' to
disable, if necessary.)
* Changes (as part of 5.0) in the `racket' language compared to the
`scheme' language: constructor-style printing, a `struct'
alternative to `define-struct' that fits more naturally with
`match' and constructor-style printing, bytecode-dependency
management via SHA-1 hashes instead of just timestamps (where the
`openssl/sha1' library provides the SHA-1 hash function), a
reorganization of `scheme/foreign' into `ffi/unsafe' and
associated libraries, and new printing functions `eprintf' and
`displayln'. Also, a generator from `racket/generator' is
required to have the form `(generator () body ...)', which
supports a planned extension to let a generator accept arguments.
* Changes to the `racket' language (since 5.0): internal-definition
positions allow mixing expressions with definitions, full
continuations can escape past a continuation barrier, custodians
can attempt to terminate subprocesses and subprocess groups (see
`current-subprocess-custodian-mode', `subprocess-group-enabled'),
the JIT supports additional unboxing flonum operations and unsafe
variants, `ffi/unsafe' provides an asychronous-call mechanism to
deal with foreign threads, a new "." modifier for format string
directives (e.g., "~.s" and "~.a") limits the respective output to
`(error-print-width)' characters.
* The core type system of Typed Racket has been substantially
revised. In particular, Typed Racket can now follow significantly
more sophisticated reasoning about the relationships between
predicates. Additionally, Typed Racket now allows variable arity
types in more places, allowing programmers to specify
variable-arity lists.
* We are working on an optimizing version of Typed Racket that takes
advantage of type information for certain classes of programs.
This project is a work in progress. For those interested, see the
documentation for `#:optimized'.
* The `web-server/formlets' library adds a `formlet*' form that
allows dynamic formlet construction, as opposed to `formlet' which
requires syntactic Xexprs and static formlets. Several new
library formlets are added.
* The `syntax/parse' library has new support for matching literals
at different phases using the `#:phase' argument for literals and
literal sets.
* RackUnit now includes a GUI test runner as `rackunit/gui'.
* The `2htdp/image' library now includes `flip-vertical' and
`flip-horizontal' operations that mirror images (vertically and
horizontally).
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