PLT Scheme version 370 is now available from
* The conservative garbage collector (CGC) has been replaced with a
precise garbage collector (3m) in the standard build. For most
users, this change simply amounts to "better performance in space
and time". For example, a long-running DrScheme instance typically
uses much less memory than before.
The new memory manager also supports a new "Limit Memory..." option
(in DrScheme's "Scheme" menu) to limit the memory use of a
programming running inside DrScheme.
For those who work with C-implemented libraries and extensions, the
switch to precise collection may complicate interoperability. To a
large extent, however, `(lib "foreign.ss")' works the same with both
collectors. (But note that the 3m is a moving collector, so be
careful with passing Scheme objects to C.)
Although our pre-built binaries use the new collector, builds from
source using the conservative collector are still supported.
* For a program written with one of the the "How to Design Programs"
(HtDP) languages, DrScheme saves the program with meta-information
that identifies the language and records the teachpacks used by the
program. DrScheme's teachpack GUI now works only with the HtDP
languages. In other languages, use `require' to access teachpacks.
The meta-information is in the form of a reader extension that turns
the file content into a `module'-based program, which means that
teaching-language files can be loaded directly into MzScheme or used
with other PLT Scheme tools.
* The HtDP "world.ss" and "image.ss" teachpacks have been revised,
including support for the creation of animated GIFs.
* Unit-based servlets are no longer supported in the web server. Use
module-based servlets, instead. (Servlets can be implemented using
a `unit' within a `module', but the web server's API is provided
through a module.)
* A new `(lib "unit.ss")' library replaces the old one and provides a
simpler and more flexible syntax. The `(lib "unitsig.ss")' library
is deprecated but still available as `(lib "unitsig200.ss")', and
the old `(lib "unit.ss")' is available as `(lib "unit200.ss")'.
((lambda (x) (x x)) (lambda (x) (x x))) Eli Barzilay:
http://www.barzilay.org/ Maze is Life!