DrScheme Release Notes
----------------------

Current Release: 43.
Release Date: August 9, 1996.

Note:
Release 44 is planned for August 28 and will include bug fixes and
better documentation for the new tools.  We encourage our users to try
release 43 and submit bug reports.  If at all possible, fixes for bugs
in release 43 will be incorporated into release 44.

Send bug reports to: plt-bugs@cs.rice.edu

The following is a summary of the changes in this release from the
previous one.

DrScheme
--------

* Added a "Preferences" item on the "Edit" menu.  The "DrScheme"
  category allows selection of the subset of Scheme from purely
  functional Scheme (no set!, etc) to (almost) fully R4RS Scheme.

* The Scheme primitives can now be redefined, and there is no longer a
  restriction on using names that begin with "zodiac:".

* These syntactic forms not yet supported: do without the step form,
  vector constants inside quasiquote, local, and define-structure (use
  define-struct instead).

* Significant internal restructuring of the GUI tools DrScheme uses to
  make windows, panels, buttons, etc.

Syntax Checker
--------------

* Added a Syntax Checker and Colorizer.

* Go to the "Tools" menu and click on "Syntax Checker."  Then, clicking
  on the "Check Syntax" button will highlight syntax errors and (on some
  platforms) color the program according to free and bound identifiers,
  syntactic forms, constants, etc.

Debugger
--------

* Added early support for a Debugger.

* After loading a file, click on "Debug."  Then, clicking on the
  beginning of an expression (a "Hotspot") will enable setting
  breakpoints and recording history information.  Better documentation
  is planned for release 44.

* Note: The Debugger currently doesn’t handle syntax errors very well.
  So, first make sure that the program passes "Check Syntax" before
  running the Debugger.

Stepper
-------

* Added support for let, let*, letrec, call/cc and improper arguments in
  lambda.

* Added Cut, Copy, Paste and Delete to the Edit menu.  Copy and Paste
  also work between the Stepper and DrScheme.

Analysis
--------

* The Analysis tool (MrSpidey) is temporarily unavailable in releases 43
  and 44 and will reappear in a future release.

Known Problems
--------------

* On some platforms (Macintosh and Microsoft Windows), the Syntax
  Checker and the Debugger do not display the program in color.

* On the Macintosh, the Debugger window is too small, and the Hotspot
  window does not pop up correctly.