
gfd_vars_exclude_range(+Vars, ++Lo, ++Hi)

   Exclude the elements Lo..Hi from the domains of Vars.

Arguments
   Vars                Collection of existing domain variable or integer
   Lo                  Integer lower bound of range to exclude
   Hi                  Integer upper bound of range to exclude

Type
   library(gfd)

Description

   Primitive for excluding the integers between Lo and Hi (inclusive) from
   the domains of variables in Vars. 

   Note that this predicate is intended for use only in implementing
   co-operation with other solvers and constraint propagators at the
   ECLiPSe level, and should not be called from ordinary user code.
   It differs from the usual constraint in that the propagation is not
   performed immediately. Normally, propagation in gecode is performed by
   a suspended goal that is scheduled and woken after each constraint is
   posted.  However, this predicate does not call the woken goal
   scheduler (wake/0), so the propagation goal may not be executed 
   immediately. (It is possible that under some circumstances the goal 
   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.

   This predicate is specific to lib(gfd), and is more efficient than
   using multiple exclude_range/2 for updating each variable in Vars,
   because this is implementing as one rather than multiple
   events.



