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(declare (type fixnum ---)) considered etc.
- To: DCP@QUABBIN.SCRC.Symbolics.COM, RAM@CMU-CS-C.ARPA
- Subject: (declare (type fixnum ---)) considered etc.
- From: Daniel L. Weinreb <DLW@QUABBIN.SCRC.Symbolics.COM>
- Date: Wed, 23 Jul 86 14:54 EDT
- Cc: common-lisp@SU-AI.ARPA, Fahlman@CMU-CS-C.ARPA, masinter.PA@XEROX.ARPA
- In-reply-to: <860723124252.9.DCP@FIREBIRD.SCRC.Symbolics.COM>
Date: Wed, 23 Jul 86 12:42 EDT
From: David C. Plummer <DCP@QUABBIN.SCRC.Symbolics.COM>
Date: Wed, 23 Jul 1986 10:39 EDT
From: Rob MacLachlan <RAM@C.CS.CMU.EDU>
It seems that FIXNUM is no less portable than FLOAT, since nothing is
guaranteed about float exponent range and precision. A Common Lisp
program which uses floats cannot be totally portable. One could take
this as an argument against the currently system of float types, but
I don't have a better solution.
Good point. The difference with fixnums is that they are (a) exact and
(b) have overflow provision (into bignums).
All this means to me is that FLOAT is wrong as well. Table 2-1, page
17, specifies "recommended" minimum sizes for the floating types. I
originally argued that these should be required minimum sizes, for
exactly the reasons we're discussing here, and I still think they should
be. A "recommendation" is meaningless if you are trying to write code
and feel secure that it will run in other implementations of CL.