The accompanying program provides an executable implementation of the 
denotational semantics for the Scheme language, as defined in R5RS. The program 
is itself written in R5RS Scheme.

Full documentation for this program is currently available at:
http://www.appsolutions.com/SchemeDS/

I highly recommend perusing the above documentation in order to understand 
the limitations and issues involved in running the provided interpreter.

The full documentation is not yet packaged in distributable form (this will 
change).

If you can't wait for the incomparable religious experience of interacting 
directly with the actual denotational semantics of the official R5RS Scheme 
language, all you need to know is right here. It's very easy to get the DS-based 
interpreter up and running in any reasonably standard Scheme.

Unzip the files into a new directory, change to that directory, run your 
favorite Scheme interpreter, and type:

	(load "repl.scm")

You should get a double angle prompt, >>, which indicates that the interpreter's 
REPL is running successfully.  You can now type Scheme expressions and, if 
they're supported by the interpreter, they should be evaluated and the result 
should be displayed.

No configuration should be required.  Scheme interpreters on which this program 
has been successfully tested include (alphabetically) Chicken, Guile, JScheme, 
Kawa, MIT Scheme (DrScheme and MzScheme, v103 and v202), PLT Scheme, Scheme 48, 
SISC, and UMB Scheme.

Be aware that the interpreter has a very small library, and is by no means 
complete.  It is intended to provide a way of interacting with the executable 
denotational semantics, not to be a complete implementation of Scheme.

The current state of the interpreter is described in the web documentation at 
http://www.appsolutions.com/SchemeDS/

Error handling is currently imperfect, and many kinds of errors will dump you 
unceremoniously into the host Scheme.  To restart the interpreter in this case, 
type:

	(repl)

Note that all definitions from the previous session will have been lost.

The interpreter supports a procedure for examining the current store 
function, i.e. the interpreter's "memory".  To dump the store, type:

	(dump-store)

For information about the format and meaning of the store, see the web 
documentation.

The interpreter supports the 'load' procedure for loading Scheme source files. 
Two sample source files are provided: factorial.scm and tak.scm. Here's a 
transcript of their use:

>> (load "factorial.scm")

Value: #t

>> (factorial 12)

Value: 479001600

>> (load "tak.scm")

Value: #t

>> (tak 12 8 4)    ; takes a while

Value: 5

>> (exit)          ; exits to host Scheme or shell prompt


Note that after running tak with the above parameters, the interpreter's store 
has been enlarged to the point where performance is noticeably reduced.  Exiting 
and restarting the interpreter using {-(repl)} is suggested.

If you have any questions, feel free to email me at anton@appsolutions.com.

===========================================================================
Copyright (C) 2002 Anton van Straaten <anton@appsolutions.com>

The accompanying program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License, 
version 2, as published by the Free Software Foundation.

This program is distributed in the hope that it will be useful, 
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, see http://www.gnu.org/copyleft/gpl.html