1:- module(julian_util, [dow_number/2]).    2
    3%%	dow_number(+DayOfWeek:atom, -Number:integer) is semidet.
    4%%	dow_number(-DayOfWeek:atom, +Number:integer) is semidet.
    5%%	dow_number(-DayOfWeek:atom, -Number:integer) is multi.
    6%
    7%	True if Number is the ISO number for DayOfWeek.
    8%   0 is Monday, 6 is Sunday. DayOfWeek is an atom like `monday`,
    9%   `tuesday`, `sunday`, etc.
   10%
   11%   This predicate supports `library(delay)`.
   12:- multifile delay:mode/1.
   13delay:mode(julian_util:dow_number(ground,_)).
   14delay:mode(julian_util:dow_number(_,ground)).
   15
   16dow_number(monday,    0).
   17dow_number(tuesday,   1).
   18dow_number(wednesday, 2).
   19dow_number(thursday,  3).
   20dow_number(friday,    4).
   21dow_number(saturday,  5).
   22dow_number(sunday,    6)