Re: Rational and complex numbers

[Guy.Steele@CMU-CS-A]

Your points are well-taken, and I'm glad they are in the record.
Originally, I suppose that the S-1 LISP implementation (of which I
one implementor) was the primary proponent of complex numbers in
Common LISP, out of a desire to be able to exploit the S-1 hardware
and yet also able to develop software in other implementations.
Hence the need for at least Cartesian complex floating-point data type.

I do foresee one entirely plausible application for Gaussian integers,
which is graphics applications.  For discrete bit-map representations,
Gaussian integers may be a very convenient representation.  Some interesting
work has been done at Yale on picture languages that use complex numbers.

I also admit once again to harboring the secret ambition for some form
of LISP to supplant FORTRAN...
--Guy