Greetings,
I'm happy to announce that our paper, "Implementing Baker’s SUBTYPEP
decision
procedure", has been accepted to the 12th European Lisp Symposium, to be
held
in Genova on April 1-2 2019. The abstract is given below.
Authors: Léo Valais, Jim Newton and Didier Verna
We present here our partial implementation of Baker’s decision
procedure for SUBTYPEP. In his article “A Decision Procedure for
Common Lisp’s SUBTYPEP Predicate”, he claims to provide
implementation guidelines to obtain a SUBTYPEP more accurate and as
efficient as the average implementation. However, he did not
provide any serious implementation and his description is sometimes
obscure. In this paper we present our implementation of part of his
procedure, only supporting primitive types, CLOS classes, member,
range and logical type specifiers. We explain in our words our
understanding of his procedure, with much more detail and examples
than in Baker’s article. We therefore clarify many parts of his
description and fill in some of its gaps or omissions. We also argue
in
favor and against some of his choices and present our alternative
solutions. We further provide some proofs that might be missing
in his article and some early efficiency results. We have not
released any code yet but we plan to open source it as soon as it is
presentable.
Léo Valais
