number syntax

[Chris Hanson <CPH@AI.AI.MIT.EDU>]

    Date: Thu, 9 Apr 87 16:19:28 cdt
    From: David Bartley <bartley%home%ti-csl.csnet at RELAY.CS.NET>

    Has anyone implemented exactness using a mechanism substantially
    different from the one Kent Dybvig describes in his new book?
    (Quoting his page 111: "In practice, the internal representation for
    an exact quantity is as an integer or ratio, and the internal
    representation for an inexact quantity is as a floating point number,
    although other representations are possible."  Also, "The exactness of
    a complex numeric object depends on the exactness of its real and
    imaginary parts.")  How do people feel about this approach?  Does this
    fulfill the spirit of exactness?  Does anyone want to pay for a more
    orthogonal exactness attribute for numbers?

    Is it permissible for an exact 3.5 to print (by default) as 7/2 or an
    inexact 2 to print as 2.0?

We have not yet implemented exactness.

    Has anyone implemented the -1+2i or 5@7 syntax for complex numbers?
    Is there strong resistance to Common Lisp's #c(-1 2) representation?

We have implemented this syntax.  I don't have strong feelings about this.