--- In

ISO8601@yahoogroups.com, "piebaldconsult" <PIEBALDconsult@...>

wrote:

> If the fractional part of a day represents a time-of-day then

> oughtn't it to be preceded by a T? If so, then wouldn't it also

> require at least one digit before the decimal point (ummm... comma)?

>

> 2006-123T0,5

That would be a half-hour past midnight, i.e. 00:30, although it

should properly be written with two 0s.

Adding an extra digit would be redundant, since the whole number part

of the fraction is the day (of month, week or year). If fractional

days were to be permitted, then the time of day should not be

permitted with the date representation. That is, a decimal fraction

is permitted only for the lowest-order component, a date with a

fractional day could not also include a time of the day

representation, since the highest-order component of the latter is the

hour.

Likewise, when representing time of the day with a decimal fraction of

the hour, you would not represent 00:30 it as :0,5 or as 0,5: but as

00,5. The time designator T is always preceded by the day, and always

followed by the hour. Thus, a representation with a fractional day

would be date-only, even though the fraction could be converted to a

time of the day.

Which is all academic, since decimal fractions of days is not

permitted by the standard, actual use thereof not withstanding. I

would also point out that decimal fractions of years are also used

(although they do not correspond exactly to the Gregorian calendar).

Decimal fractions of months would be difficult to implement, however.

John Hynes

www.decimaltime.org

2006-09-27T11,0Z