weekday – Generate "day of week"

Macros \weekday{yyyy}{mm}{dd} (yields day name) and \weekdaydate{yyyy}{mm}{dd} (yields date print-out, including day name). You may use \year, \month, \day, to generate today's day name.

The code bears a note about year 2000 compatibility; it is not clear whether it will be workable in our present post-millennial state.