From: Eli Barzilay <firstname.lastname@example.org> To: email@example.com Subject: [PLT announcement] PLT Scheme v4.2.4 Date: Thu, 28 Jan 2010 21:32:33 -0500 PLT Scheme version 4.2.4 is now available from http://plt-scheme.org/ * The `scheme/flonum’ and `scheme/fixnum’ libraries provide flonum- and fixnum-specific operations. In the case of flonum-specific operations, the JIT compiler can recognize combinations of operations (including local bindings) and improve performance by "unboxing" intermediate results. * The `scheme/unsafe/ops’ library provides arithmetic and other operations that are implemented without dynamic checks. Avoiding checks can sometimes improve performance, but at the expense of safety. * `2htdp/universe’: We have severed the connection between universe and an image library and made a few other, minor changes. Most programs will now have to change to require the `htdp/image’ library explicitly. For the full details, see the new Porting World Programs section of the documentation: http://docs.plt-scheme.org/teachpack/2htdphtdp-port.html * The `2htdp/image’ library continues to grow. In this release, it is supported by `2htdp/universe’, equality changed to be based on how the images are drawn, cropping and curves were added, and support for more kinds of pens were added. * `htdp/world’: The old world teachpack remains deprecated. HtDP/2e exclusively uses the new 2htdp/universe library. For backwards compatibility, the world teachpack will remain in the distribution until the coming summer. * The `scheme/class’ library now provides `this%’, which refers to the class of the current object (i.e. `this’). * `scheme/generator’ has convenient functions for infinite generators, and for converting a generator to a sequence for iteration. * PLT Scheme’s add-on directory can be customized by the $PLTADDONDIR environment variable or `--addon’/`-A’ command-line flags. This controls where downloaded Planet packages and their compiled Scribble documentation are installed. * Additional extensions include: saving `errno’ in foreign calls, much improved `sort’ speed, normalized results from `procedure-arity’, and more. [Note that mirror sites can take a while to catch up with the new downloads.] Feedback Welcome, -- ((lambda (x) (x x)) (lambda (x) (x x))) Eli Barzilay: http://barzilay.org/ Maze is Life!