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Re: My ideas about infinity in Scheme (revised)

This page is part of the web mail archives of SRFI 70 from before July 7th, 2015. The new archives for SRFI 70 contain all messages, not just those from before July 7th, 2015.

 | Date: Sat, 21 May 2005 14:39:59 -0700
 | From: Alef Null Petrofsky <al@xxxxxxxxxxxxx>
 | > From: Aubrey Jaffer <agj@xxxxxxxxxxxx>
 | > How about "1/0." and "-1/0."?
 | Something I'd just like to throw out there is that one can represent
 | the inexact floating-point entities "NaN" and positive and negative
 | "infinity" without extending the r5rs BNF at all, by using #i0/0,
 | #i1/0, and #i-1/0.

Those would work.

The #e and #i prefixes are not one of the better Scheme inventions:
#e-5 puns 1#e-5; #i-1/0 suggests an imaginary infinity to

 | (I implemented this for kawa back in 1998, but I don't know whether
 | kawa still uses that notation.)

Kawa 1.7.90 accepts #i1/0, #i-1/0, and #i0/0; also #e1/0 and #e-1/0.
[but chokes on 1#.e-5]