
excl_range(?Var, ++Lo, ++Hi)

   Exclude the elements Lo..Hi from the domain of Var.

Arguments
   Var                 Integer variable or integer
   Lo                  Lower bound of range to exclude
   Hi                  Upper bound of range to exclude

Type
   library(ic_kernel)

Description

   Primitive for excluding the integers between Lo and Hi (inclusive) from
   the domain of an integer variable.  The call may fail (when the domain of
   Var has no elements outside the range Lo..Hi), succeed (possibly updating
   the variable's domain), or instantiate the variable (in the case where
   the domain gets restricted to a singleton value).

   Note that this predicate is intended for use only in implementing
   constraint propagators, and should not be called from ordinary user code.
   It differs from the usual constraint predicates with respect to the
   execution of delayed goals.  If the call to excl_range/3 results in a
   domain change, any delayed goals suspended on that change will be
   scheduled for execution, as normal.  However, excl_range/3 does not call
   the woken goal scheduler (wake/0), so these goals may not be executed
   immediately.  (It is possible that under some circumstances the goals
   will be executed, if wake/0 is called indirectly - one example would be
   by the unify handler if the variable becomes ground - but this should not
   be relied upon.)  To ensure that the goals are eventually executed, the
   caller should arrange for wake/0 to be called at some appropriate point
   in the subsequent execution.  Please see the "Advanced Control Features"
   section of the User Manual for more information about woken goal
   management.


Examples
   [eclipse 3]: X :: 0..10, excl_range(X, 4, 7).
X = X{[0 .. 3, 8 .. 10]}
Yes (0.00s cpu)

[eclipse 4]: X :: 0..10, excl_range(X, 9, 20).
X = X{0 .. 8}
Yes (0.00s cpu)

[eclipse 5]: X :: [2, 4, 6 .. 10], excl_range(X, 4, 12).
X = 2
Yes (0.00s cpu)


See Also
   excl / 2
