17 October, 1996

Announcing version 1.3 of EnvDraw, an instructional package for STk.

EnvDraw is a environment diagramming package which draws environment
diagrams as taught in Abelson and Sussman's _Structure and
Interpretation of Computer Languages_.  It was written as an
instructional tool for the CS61A course at the University of
California at Berkeley.  The environment diagrammer is a metacircular
evaluator which draws procedures, environments, and box and pointer
diagrams along with all the accompanying symbols and mutation.  It
includes a box and pointer diagrammer which handles circular list
structures, cons cell mutation, and also will watch for modification
of any symbols known to be pointing to drawn cells.

			     REQUIREMENTS

EnvDraw works with STk 3.1.1 (Dont use 3.1, its broken!).  Slib must
be installed.  Optionally, a patch to error.c in the source
distribution allows the metacircular evaluator to catch errors nicely.

			   Getting EnvDraw

I have placed a copy of envdraw-1.3.tar.gz in the following places:

ftp://ftp.xcf.berkeley.edu/pub/envdraw/envdraw-1.3.tar.gz

in the incoming directory of the scheme repository:

ftp://ftp.cs.indiana.edu/pub/scheme-repository/incoming/envdraw-1.3.tar.gz

in the incoming directory of the STk home site:

ftp://kaolin.unice.fr/pub/incoming/envdraw-1.3.tar.gz

			      INSTALLING

Pick a directory to install the EnvDraw sources in.  If you would
like to install the sources as a subdirectory of your home directory
and the envdraw-1.3.tar.gz file is located in the same directory,

% cd ~
% gunzip envdraw-1.3.tar.gz
% tar -xf envdraw-1.3.tar

This extracts a subdirectory named envdraw-1.3 with a number of files.
The files are organized as follows:

envdraw-1.3/Help/	HTML help files
envdraw-1.3/doc/	Postscript and LaTeX documentation
envdraw-1.3/icons/	Icons used by Tk
envdraw-1.3/diffs/	The optional diff to error.c described above
envdraw-1.3/test/	Some tests
envdraw-1.3/lib/        Initialization shell and scheme scripts.
envdraw-1.3/*.stk	The source files

See the file envdraw-1.3/lib/envdraw.sh for an example of a Bourne
shell script that has all the required environment variables set.