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Re: My ideas about infinity in Scheme (revised)



 | 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
non-schemers.

 | (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]