Reflections on the Future History of Arming Bears

A precis for a proposed ~45 minute talk in the Online Lisp Series

Mark Evenson
Created: 10-JUN-2020
Revised:  <2020-06-10 Wed 16:03>

With the recent releases of Armed Bear Common Lisp over the past six
months, the future of extending the implementation has come into
sharper focus.  The majority of this work has occurred within the head
of one individual with little chance for public review and reflection.
We believe that our externalized exposition of the reasoning behind
these efforts will be of interest to those interested in the future
history of Common Lisp implementations.

In the past few months, we released abcl-1.6.0 in which we extended
the set of underlying Java Virtual Machines (JVM) that the
implementation runs on to include openjdk11 and openjdk14 while
maintaining compatibilty with openjdk6.  With the internal
overhaul or arrays specialized on unsigned bytes in abcl-1.7.0, we
made it possible to share such byte vectors with memory allocated
outside of the hosting JVM via system interfaces such as malloc().  

We first present a brief prehistory on the Armed Bear Common Lisp
Implementation.  Then, we first present the goals and challenges in
affecting these changes within the ABCL codebase by showing examples
from recent experience.  Then, we use this initial exposition to serve
as a springboard to discuss outstanding needed changes in the ABCL 1
branch, and to outline some of the features intended to be present in
ABCL 2, due to be released in the Fall of 2020.