On Jan 20, 2011, at 4:46 AM, Edward C. Zimmermann wrote:
> ISO 8601 is, in fact, a standard format for user input.

That's an interesting point of view.  The last time I read that
spec, though, I remember it making an explicit statement 
that as far as the WG knew the format was not a common
culturally expected format in any language, culture, or locale,
and regarding this as an advantage in that it did not favor
or appear to favor any one cultural practice over another.

So if you mean that ISO 8601 is intended to serve as a way
to make sense of input from general or untrained users, I
think the historical facts of the matter are against you. 

If you only mean that it's a text format and thus typable, then of
course you're quite right, but the observation is perhaps less
compelling.  A date format using integers counting the number 
of days since the death of Julius Caesar (or any other epoch)
is also a text format and readily typable; would anyone say
it's a format for user input?

It's quite true that many formats designed and specified for
interchange may prove to be suitable for input from at least
some users; I know a few technically oriented people
who have acquired the habit of using ISO 8601 dates in
their daily life because they like the format.  

But designing a format to accept and handle unstructured
input from users who are not trained in the details of the format,
and designing a format for interchange among software
systems which may be expected to do some validation of
their input are (in my experience at least) two rather different
activities.  Most obviously, in most data interchange applications,
it's usually regarded as preferable to eliminate as much
variation as possible in formats:  if there is no difference in
meaning between "2011-01-21" and "20110121", people
interested solely in the exchange of data among databases
will (again, in my experience) unanimously prefer to choose
one of these formats and require it, rather than allowing
either.  That seems good practice to me.


* C. M. Sperberg-McQueen, Black Mesa Technologies LLC