First Try at Terminology

[David A. Moon <Moon@STONY-BROOK.SCRC.Symbolics.COM>]

I might quibble with one or two details, in particular the idea that it
is possible to prevent programmers from discovering and depending upon
what a particular implementation does in a particular undefined
situation, however on the whole this seems pretty good.  I'd like to
see the terminology for erroneous situations tightened up for all of
Common Lisp, not just CLOS.

I don't think that it's the business of the CLOS subcommittee to do this.
In other words, I'm uncomfortable with the idea that "the CLOS
subcommittee of X3J13 is the only subcommittee that ever does anything"
(incidentally this is not quite true) implies that "the CLOS
subcommittee should do everything."

We can use a working terminology in our deliberations, but we should
be prepared to convert to whatever standard terminology is defined for
Common Lisp as a whole, when that happens.  This suggests that we should
do something fairly simple and not develop an elaborate formalism.
Simply separating the cases of "an error is always signalled", "an error
is signalled unless you tell the compiler not to check for it", "the
effect is undefined", and "the effect is implementation-dependent"
seems sufficient to me.