Re: character objects & representation issues

[Daniel L. Weinreb <DLW at MIT-AI>]

Ah.  I see.  You mention to motivations for character objects; one
works fine in "my" proposal (the one I construed out of what I think
GLS is saying; I take no credit), but the other has problems.

First, you want character objects for debugging, so that when you see a
capital A you can tell that it is a capital A rather than a 101 octal.
With "my" proposal, you do indeed get this, so long as you do your
debugging in NIL rather than on the Lisp Machine.  I don't think
anyone has objections to this.

Secondly, you want character objects to print differently.  Presumably
a capital A prints as #/A, rather than as 101.  This would not work in
"my" proposal.  If you ran the portable FOOBAR on the LispM, and it
prints a data structure, and then you run FOOBAR in NIL and it reads it
back in, then character objects can get converted to fixnums.  I don't
see any solution to this problem, other than to meekly suggest that
maybe it is just not a very common thing.  Code that wants to print
character for human eyes can be made portable by going through a FORMAT
control option whenever printing character objects, rather than ever
using PRINT directly.