DrScheme Release Notes

Current Release: 45
Release Date: November 12, 1996.

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

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

DrScheme

• Scheme I/O through read, read-char, and read-line is now supported. All I/O is specially boxed in the interactive console to distinguish it from evaluator I/O.
• Two syntactic forms are not yet supported: do without the step form and define-structure (use define-struct instead).

Analysis

• The Analysis tool (MrSpidey) is temporarily unavailable in release 45 and will reappear in a future release.

MrEd

• A new construct has been added: eventspaces. An eventspace encapsulates an independent event loop. A single running MrEd can contain multiple eventspaces, each owning a collection of top-level windows that are connected through the event loop, but indepedent of event-handling for other eventspaces. This supports a better integration of asynchonous threads and synchnous eventspaces.
• A prototype Web browser is available through the standard "Open URL..." menu item in the "File" menu.
• See plt/mred/HISTORY and plt/mred/system/history in the distribution for more information and other changes.

MzScheme

• Multiple return values are now agressively supported, and new forms define-values, letrec-values, set!-values, etc. have been added.
  IMPORTANT: The let-values of previous versions is now let*-values. The new let-values binds a sequence of identifier sets all with the same enviornment.
• See plt/mzscheme/HISTORY in the distribution for more information and other changes.

Known Problems

• DrScheme internally normalizes pathnames, resolving all links to absolute paths. This causes problems with systems that use automounting.
• Even in the R4RS language level, DrScheme does not support case-insensitive identifiers.
• The eval procedure is not supported.
• See also plt/openbugs in the distribution.