
?X &=< ?Y

   X is before or equal to Y in the domain order

Arguments
   X                   variable or domain value
   Y                   variable or domain value

Type
   library(ic_symbolic)

Description

	Constrains X and Y such that X is before Y or the same as Y in the
	domain order.
	X and Y must be variables or values of the same domain. If one of
	them is domain-less, it will be given the same domain as the other.


Modules
   This predicate is sensitive to its module context (tool predicate, see @/2).

Examples
   
    ?- [X,Y] &:: weekday, X &=< Y.
    X = X{[mo, tu, we, th, fr, sa, su]}
    Y = Y{[mo, tu, we, th, fr, sa, su]}
    There is 1 delayed goal.
    Yes (0.00s cpu)

    ?- mo &=< th.
    Yes (0.00s cpu)

    ?- X &=< th.
    X = X{[mo, tu, we, th]}
    Yes (0.00s cpu)

    ?- fr &=< th.
    No (0.00s cpu)

    ?- X &=< Y.
    Arguments have no domains in X &=< Y in module eclipse
    Abort

    ?- X &:: weekday, X &=< red.
    Arguments have different domains (weekday,colour) in X &=< red ...
    Abort
    

See Also
   &=< / 3, &< / 2, &> / 2, &>= / 2, &= / 2, &\= / 2, shift / 3, rotate / 3, domain / 1
