[idn] Least Astonishment (was: Re: canonicalization)

[John C Klensin <klensin@jck.com>]

--On Sunday, May 28, 2000 10:04 +0800 James Seng
<jseng@pobox.org.sg> wrote:

>...
> Cool. Do you want to define "Principle of Least Astonishment"? 
>...

The Principle (or Law) of Least Astonishment dictates that, if
an action is taken, and there are choices about what outcome
should result, the outcome should be chosen that is least
astonishing to the typical user.  Stated quite differently, if
common sense (or even logic) is applied to a particular
circumstance, the actual outcome should correspond closely to
the prediction.

This can be an extremely difficult criterion in the IDN case
(and may not completely overlap with other criteria as has been
suggested) because differences in local assumptions about how
characters should be mapped or sorted may lead to differences in
"common sense" predictions of behavior and we seem to be in
agreement that the same inputs should always (globally) produce
the same results.  Nonetheless it is very important, especially
for the DNS where the users and arbiters (e.g., lawyers and
politicians) legitimately believe that their interpretations of
how names ought to behave are at least as important as narrow
technical concerns.  And they, of course, can (will) only apply
[their view of] common sense, not the esoterica of mapping rules.

   john