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@node A Bigger Picture
@chapter A Bigger Picture

Here's a larger perspective on some of the motivations for the
Hackerlab C library:

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Date: Fri, 27 Jul 2001 23:43:50 -0700 (PDT)
From: Tom Lord <lord@@regexps.com>
To: gcc@@gcc.gnu.org
Subject: a .NET alternative (GJC et al)
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This note is about Free Software implementations of high-level
programming languages, including Java and Scheme.  It think it
pertains to GJC, and more generally, to the strategic direction of all
of our language implementations.  At the end of the note there is a
project announcement, requesting participation and support.  The note
begins with some background and motivation.
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I think it is widely recognized, nowadays, that a good approach to
implementing high level languages is to build a common run-time system
on which they run.  The run-time system provides the low-level
functionality these languages have in common, and is a foundation upon
which interoperability between languages can be built.
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It seems to me that Microsoft has come to some similar conclusions, as
evidenced by their inventing and committing to a low level language
that is designed with precise garbage collection in mind (C#), and
using that language to implement a run-time system supporting multiple
languages.  Good for Microsoft!
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I'm concerned about the run-time systems we currently use.  Here are
two reasons that indicate some of my thinking: (1) we seem to have
systems that rely on conservative garbage collectors, which makes
these implementations needlessly unreliable; (2) we don't seem to have
any projects to build a common run-time system, designed to support
several languages (we have Guile, designed to be a multi-lingual
Scheme, but that's not quite the same thing).
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It seems to me that there is now an opportunity and some choices for
the Open Source community.  
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The opportunity is to build a new Free Software run-time system,
providing a precise collector, and support for multiple languages.
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The choices are (1) whether to re-implement the specifications offered
by Microsoft, or try to implement something better, and (2) whether to
tie the implementation of a new run time system to a specific compiler
(GCC, presumably) or try to build something more portable.
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The unofficial strategy of the Open Source community seems to be, in
the always-immortal words of Yogi Berra, "When you come to a fork in
the road, take it."  Thus, for example, we've already seen Java
implementors carve out distinct regions of the implementation design
space, resulting in a pleasing choice of Java implementations for
users.
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There have been announcements in the news recently about the
possibility of building an Open Source clone of C# and .NET.  That's
one branch of the fork, and one that is practically guaranteed to find
commercial support.  I'm not terribly familiar with C#, but what
little I've read looked like a respectable design.  So if part of the
Open Source community commits to that branch of the fork, I'd bet
they'll meet with some form of success.
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But I've always thought that Free Software was about more than just
cloning Microsoft software.  I like to believe that Free Software is
also about creatively exploring new ideas and having the kind of fun
that comes from trying to build something "better".  So I'm interested
in a different branch of the run-time system design space.
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In particular, I've been working towards a run-time system in C, not
C#, supporting multiple high level languages, and providing a a
precise garbage collector (along with lots of other nice features).
My intention is to build a portable implementation, not tied to any
particular compiler.  I have a foundation for my proposed run-time
system: it's called the Hackerlab C library, and its available at
www.regexps.com.  There's a long way to go, but I think the foundation
has several good ideas, implemented and tested well.
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In addition to the code that's there, I have some pretty clear ideas
about what else needs to be built: how to add thread support, how to
build up the Unicode support, what kinds of data structures, and how
to finish the I/O subsystem.  I have less clear ideas, and think a
little bit of experimentation is in order, about what kind of C
interface to provide to the garbage collector, and how to support
binary object externalization (for persistence and migration of
objects).
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So if you're interested in high level language implementations, such
as GJC, please have a look at my web site.  There are some initial
suggestions for how to participate which you can find in the Hackerlab
C Library reference manual, though if the project really takes off,
we'll clearly need to make participation more open and more formal.
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I also need some money to work on this project -- badly.  My web site
implements a form of the "street performer protocol", and that is one
way to help fund further development.  I'm also happy to discuss
employment and consulting opportunities that might be out there.
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Thanks for your attention,
happy hacking, 
peace, love, and penguins,
fondest regards,
over and out,
your eccentric and always friendly Internet pal,
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Tom Lord
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