Implementing functional languages
	~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
	Simon Peyton Jones and David Lester
	Prentice Hall 1992

Overview
~~~~~~~~
In the Spring of 1992 Prentice Hall will publish the above book.  This
book gives a practical approach to understanding implementations of
non-strict functional languages using lazy graph reduction.

The main unusual feature of the book is that the text of each chapter
is itself a directly-executable Miranda(TM) program, constituting a
minimal but complete compiler and interpreter for a particular
abstract machine.  The complete source code for the book is available in
machine-readable form by network file transfer (FTP). [Details below.]
A Tutor's Guide, containing solutions to the exercises, is also available
from the authors. 

A second feature is a substantial chapter on the Three Instruction
Machine (TIM).  Most functional language implementors know something
of TIM, and there have been quite a few research papers about variants
of it, but I believe this is the first published unified treatment,
covering arithmetic, data structures, let(rec) expressions and so on,
in a single framework.

Written to allow the reader to modify, extend and experiment with the
implementations provided in the text, we hope that this book will help
to make a course on functional-langauge implementation "come alive".

The main topics covered are:

	* A "core" language, including a parser and pretty printer.
	* A template-instantiation implementation
	* The G-machine
	* The three instruction machine (TIM)
	* A parallel G-machine
	* Lambda lifting and full laziness
	
This book differs from Simon's earlier book on functional-language 
implementations in the following ways

	* it is intended as a course text;
	* it has executable examples of everything discussed (including
		a pointer-reversing garbage collector...);
	* it has a substantial chapter on TIM, which was not covered
		at all in the earlier book;
	* the treatment of full laziness is new, based on
		the ideas in our paper in Software P&E (May 1991)

Release information
~~~~~~~~~~~~~~~~~~~
The patch level of this release is given in the Makefile

The file Release-history tells the changes since the last release.

What is here
~~~~~~~~~~~~
This directory contains material to allow you to build:
 
	- the installation guide
	- the book
	- executable Miranda sources for the implementations described

To get started, print the installation guide, which is in the DVI file

	installation.dvi

It should tell you how to do everything else.  If it doesn't exist, type

	make installation.dvi

Important 
~~~~~~~~~ 
These sources contain the complete source text for the book, both
executable and typesettable, so you can print yourself a copy (about
300 pages).  Needless to say, we'd won't get any of those lovely
royalties if everyone uses their laser-printer rather than their
bookshop; so please buy a copy too when it is in print!  And of
course, please don't reproduce lots of copies.  Meanwhile, we're happy
for you to print individual copies.

The book should be published in the Spring of 1992.

Tutor's guide
~~~~~~~~~~~~~
The solutions to the exercises are collected in a Tutor's Guide, which 
isn't included (because then students would have access to the answers too).
If you want the solutions, write to Simon on your departmental letterhead,
including your email address, and he'll send you the stuff.

Bugs
~~~~
It is quite possible that something won't go smoothly when you try to
build the system as described in the installation guide.  Please let
Simon know if you encounter any problems, and (preferably) how you solved
them, so he can improve the installation guide.

Likewise, the content of the book may well contain errors.  Please tell us
if you find any.

Mailing list
~~~~~~~~~~~~
We would like to have some idea of who is using this material.  If you
have FTP'd the material to your site, please email Simon to say so.

Using this information, we'll keep you informed about bug-fixes and
improvements to the machine-readable sources.



Have fun!


Simon Peyton Jones	[email protected]
David Lester		[email protected]