[XSLT2.0] formatting zero components of a dateTime

We have aligned the formats used in format-date() with those used in
xsl:number. However, this overlooks the fact that components of the time can
have a value of zero, which cannot arise with xsl:number. A format of "01"
for minutes or seconds is reasonable, and should cause zero to be output as
"00". However, some other format tokens such as "I" and "a" don't make sense
with fields that allow zero values. The spec needs to say something about
this.

 

Michael Kay

(problem raised by a Saxon user)