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Re: issue BOGUS-FIXNUMS (initial draft)

I can't see getting entirely rid of FIXNUMs and adding something else just
because FIXNUMs aren't really portable. I think it might be more reasonable to
be more explicit about how unportable FIXNUMs are. 

Certainly implementations that have only one representation can arbitrarily
deftype FIXNUM to be SIGNED-BYTE 32 and leave it at that. 

To put it in terms of the proposal: I don't think that the problem statement as
written establishes that there is a significant problem with the language; there
may be a problem with CLtL and with CL programming texts and lots of the CL code
running around, but I think it is OK for the language to have some portable way
of talking about the "most efficient number range". All computers that I know
about have word sizes. 

I certainly would like to discourage programmers from using FIXNUM for
discrimination when they really don't mean it, and from using FIXNUM
declarations when they really mean a given number range, but I don't think
taking FIXNUM out of the language is the proper way to do it. 

I don't see how MAX-INTEGER-LENGTH has anything to do with the problem as
stated. I think it is a separate proposal, if you want to allow for limits on
bignum size.