Re: [FWP] Copying hashes

[kragen@pobox.com (Kragen Sitaker)]

Ronald Kimball wrote:
> It does not matter whether the optimization is intuitive or not.  The
> optimization is completely hidden from the user; there is no need to intuit
> it.  The behavior would be the same as it always has been.

This is true as long as the difference in performance is not
observable, and thus is not part of the "behavior".

In Alexander Stepanov and Meng Lee's paper on the Standard Template
Library, they make the argument that at least big-O performance should
be considered part of a library's interface.   (Upon rereading, it
seems that perhaps this is only implicit; the paper is available from
http://www.cs.rpi.edu/~musser/doc.ps.)

Section 2.2 of "Good News, Bad News, How to Win Big", named "Good Lisp
Programming is Hard", makes a similar case, claiming that the death of
Lisp is largely derived from the invisibility of performance
tradeoffs.  It's available at
http://cbl.leeds.ac.uk/nikos/tex2html/examples/good-bad-win/node10.html
and http://www.cs.umbc.edu/www/graduate/rpg/node10.html, among other
places.

-- 
<kragen@pobox.com>       Kragen Sitaker     <http://www.pobox.com/~kragen/>
The Internet stock bubble didn't burst on 1999-11-08.  Hurrah!
<URL:http://www.pobox.com/~kragen/bubble.html>
The power didn't go out on 2000-01-01 either.  :)


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