2006年11月21日

[cola:10453] PLT Scheme v360

PLT Scheme version 360 is now available from

http://download.plt-scheme.org/

* DrScheme now has a macro stepper that traces through macro expansion
step by step. The graphical display uses colors to illustrate
bindings and a side-panel to display additional syntax information.
For additional information and an illustrated introduction, see

http://www.ccs.neu.edu/home/ryanc/macro-stepper

* PLT Scheme now includes a new "Lazy Scheme" language level, similar
to MzScheme (with a few added libraries), but with call-by-need
semantics. There is also a "lazy" collection that can be used to
mix lazy code with eager code (put the former in a module that uses
(lib "lazy.ss" "lazy") as its language module).

* New support for prompts and composable continuations, closely
resembling Dorai Sitaram's tagged `%' and `fcontrol' operators. The
new "control.ss" library provides implementations of many other
delimited-continuation operators, including `prompt', `control',
`shift', `reset', `spawn', `splitter', and `cupto'. Moreover, these
operators all work in a reasonable and useful way with each other,
with `dynamic-wind', and with continuation marks (which can be used
for dynamic variables).
For more information, see Sitaram's papers at
http://www.ccs.neu.edu/scheme/pubs/

* Regexp support now includes the usual collection of
"Perl-compatible" features: numeric quantifiers, backreferences,
character classes, Unicode predicates, case-insensitive mode,
multi-line mode, lookahead, lookbehind, non-backtracking, and
conditionals --- all with improved performance.

* Compiler improvements include a lambda-lifting pass and better
handling of `call-with-values'.

* The "readline" collection is now included. MzScheme cannot load
this library by default, since linking to GNU readline would require
licensing PLT Scheme under GPL instead of LGPL. However, you can
link readline yourself by adding

(when (regexp-match? #rx"xterm" (getenv "TERM"))
(dynamic-require '(lib "rep.ss" "readline") #f))

in your "~/.mzschemerc" to use readline for MzScheme's REPL.

Feedback welcome,
--
((lambda (x) (x x)) (lambda (x) (x x))) Eli Barzilay:
http://www.barzilay.org/ Maze is Life!

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投稿者 xml-rpc : 2006年11月21日 02:53
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