[r6rs-discuss] [Formal] Clarification of chapter 1 overview bits re: exactness and complex numbers

Jeff Read bitwize at gmail.com
Sat Jan 20 11:35:51 EST 2007

This message is a formal comment which was submitted to formal-comment at r6rs.org, following the requirements described at: http://www.r6rs.org/process.html
Submitter: Jeffrey T. Read
Email Address: bitwize at gmail.com
Type of issue: Simplification
Priority: Trivial
R6RS component: Presentation
Report version: 5.92
Summary: The overview of Chapter 1 can be read as implying that all
complex arithmetic is exact.

On page 6, in the introductory material of Chapter 1 dealing with
arithmetic, is the following:

"Scheme distinguishes between exact arithmetic, which corresponds to
the mathematical ideal, and inexact arithmetic on approximations.
Exact arithmetic includes arithmetic on integers, rationals, and
complex numbers."

The second sentence in the above passage is ambiguous, and a casual
reading suggests to the reader that all arithmetic on integers,
rationals, and complex numbers is exact. Section 9.9 puts the lie to
that notion, so the report would benefit from the clarification of the
statement. One possibility is the following:

"Candidates for exact arithmetic include integers, rationals, and
complex numbers."

More information about the r6rs-discuss mailing list