PLT Scheme v4.1.5

posted by Eli Barzilay

PLT Scheme version 4.1.5 is now available from http://plt-scheme.org/

• Web Server:
  • new URL-based dispatching library web-server/dispatch,
  • customizable continuation serialization policies for the stateless web language web-server/stuffers,
  • abstraction of serve/servlet to build simpler dispatchers web-server/servlet-env,
  • HTTP Digest authentication support web-server/http/digest-auth,
  • built-in cookie support in web-server/http/cookie and web-server/http/cookie-parse,
  • highlighting and pretty-printing of errors in Xexpr constructions,
  • load control dispatcher for limit concurrent sessions web-server/dispatchers/limit.
• Scribble:
  • Literate programming is now available using the new scribble/lp language.
  • A new at-exp language makes it convenient to use the scribble reader’s @-expressions for general code.
  • The scribble/text preprocessor language has been extended to deal with indentation and other formatting issues.
  • The “scribble” command-line tool accepts a --pdf flag to render PDFs (via pdflatex).

• DrScheme now provides feedback when PLaneT downloads and installs new packages.

• Units & Contracts:
  • Elements of unit signatures can now be associated with contracts via the contracted signature form.
  • A contract combinator for units, unit/c, has been added.
  • The new with-contract form provides a nestable submodule contract boundary, protecting a group of definitions from the surrounding code with contracts.
  • The define/contract form has been reworked and new define forms have been added: define-struct/contract and define-unit/contract.

• Language levels and teachpacks from the DeinProgramm project for the German textbook “Die Macht der Abstraktion” by Herbert Klaeren and Michael Sperber have been added.

• Misc:
  • Typed Scheme now comes with several more pre-wrapped libraries, found in the typed collection.
  • The xml and html collections are now contracted.
  • Binding parsing in net/cgi now interacts with net/uri-codec’s configuration parameters.
  • DrScheme captures logging output.
  • Check syntax: it is now possible to tack arrows crossing the currently selected text.
  • New bitwise-bit-field function.
• The usual pile of bugfixes. (Notable: scheme/package works, deflate compression fixed, DrScheme language dialog issue resolved, match fixes, Windows networking, and much more.)

[Note that mirror sites can take a while to catch up with the new downloads.]

Feedback Welcome.

nice. I’m new to scheme and using plt scheme to build a web prototype…

After years of C++, I must say I love the language and environment.

I really appreciate the work you guys put into this - will be nice to have the url aliasing of this release.

— gord, 22 March 2009

We’re glad you like it! I’d be very interested to know any of the problems you do have with the Web framework, because I might be able to make it even better.

— Jay McCarthy, 22 March 2009

Pretty cool stuff dude!

RT www.Privacy-Center.net

— Harold Fowler, 22 March 2009