lib/gecoder/interface/constraints/set_enum/operation.rb in gecoder-0.7.0 vs lib/gecoder/interface/constraints/set_enum/operation.rb in gecoder-0.7.1

@@ -12,11 +12,35 @@
     end_code
   end
 end
 
 # A module that gathers the classes and modules used by operation constaints.
-module Gecode::Constraints::SetEnum::Operation
-  # Describes a stub started with a set enumeration followed by a set operation.
+module Gecode::Constraints::SetEnum::Operation #:nodoc:
+  # Describes a CompositeStub for the enumeration operation constraint, which 
+  # constrains the result of applying an operation between all set variables in 
+  # a set enumeration. 
+  # 
+  # The supported operations are:
+  # * union
+  # * disjoint_union
+  # * intersection
+  # * minus
+  # 
+  # == Example
+  # 
+  #   # The union of all set variables in +sets+ must be subset of 1..17.
+  #   sets.union.must_be.subset_of 1..17
+  #   
+  #   # The intersection of all set variables must equal [1,3,5].
+  #   sets.intersection.must == [1,3,5]
+  #   
+  #   # The union of all set variable must be a subset of the set variable
+  #   # +universe+.
+  #   sets.union.must_be.subset_of universe
+  #   
+  #   # The same as above, but reified with the boolean variable 
+  #   # +is_within_universe+. 
+  #   sets.union.must_be.subset_of(universe, :reify => is_within_universe)
   class ExpressionStub < Gecode::Constraints::Set::CompositeStub
     def constrain_equal(variable, params, constrain)
       enum, operation = @params.values_at(:lhs, :operation)
     
       if constrain
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