Re: Scheme as a standard extension language

[Cris Perdue <clam!cperdue@sun.com>]

Dan,

It is possible in principle to make small Common Lisp applications by
using just part of the language, but there is a problem.  Common Lisp
defines no layers, so it is impossible to decide which parts of the
language can be avoided to reduce the size of an application.  I
believe that most implementations are rather intertwined: support for
one language feature tends to rely on more of the rest of the language
than one might imagine.  Many of these dependencies can be eliminated
if need be, and if we know which ones to eliminate.

One big advantage of Scheme is that the base language is such a layer.
Also, when one uses a language plus a set of libraries, it is usually
possible to find out the dependencies among the libraries and to find
out what features require large amounts of runtime support.

This is in addition to the benefits Scheme provides by not carrying
around a lot of features for backward compatibility.  The
implementations become smaller and the language becomes intellectually
simpler and cleaner.