[plt-dev] Release Announcement for v4.2.4

From: Matthias Felleisen (matthias at ccs.neu.edu)
Date: Thu Jan 28 09:46:52 EST 2010

On Jan 27, 2010, at 9:16 PM, Eli Barzilay wrote:

> The release announcement sketch that I have so far is below.  Please
> mail me new items and/or edits.  (This is close to the final version.)
> The one item that is still missing, IMO, is:
>    * [Matthias] `error' in teaching languages?  universe/world  
> changes?
>      `random', `gensym', `current-millisecond', `sleep', `assoc',
>      `with-i/o-from-to' added?

Robby had prose for error, and I agreed with it. The others aren't  
worth mentioning.

> ----------------------------------------------------------------------
> * 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 intimate connection between
>  universe and the image library.  The most important change is that
>  the design of world programs now demands the use of two
>  teachpacks: 2htdp/universe and htdp/image (the old image library)
>  or 2htdp/image (the new image library).  Furthermore, the
>  callbacks for world programs no longer use symbols but strings.
>  The image functions are overloaded so that both strings and
>  symbols work as inputs.
>  For upgrading your world programs, see the new Porting World Programs
>  guide in the HtDP/2e section of the documentation.
> * 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.
> ----------------------------------------------------------------------
> -- 
>          ((lambda (x) (x x)) (lambda (x) (x x)))          Eli  
> Barzilay:
>                    http://barzilay.org/                   Maze is  
> Life!
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