operation.rb in gecoder-0.9.0

- old
+ new
@@ -1,60 +1,69 @@
-module Gecode::SetEnumMethods
-  Gecode::Constraints::Util::SET_OPERATION_TYPES.each_pair do |name, type|
-    next if type == Gecode::Raw::SOT_MINUS # Does not support this constraint?
+module Gecode::SetEnum
+  module SetEnumOperand
+    # Produces a SetOperand representing the union of all sets in this
+    # enumeration.
+    #
+    # ==== Examples 
+    #
+    #   # The union of all sets in +set_enum+.
+    #   set_enum.union
+    def union
+      set_operation(:union)
+    end
     
-    module_eval <<-"end_code"
-      # Starts a constraint on the #{name} of the sets.
-      def #{name}
-        params = {:lhs => self, :operation => #{type}}
-        Gecode::Constraints::SetEnum::Operation::ExpressionStub.new(
-          @model, params)
-      end
-    end_code
+    # Produces a SetOperand representing the intersection of all sets in this
+    # enumeration.
+    #
+    # ==== Examples 
+    #
+    #   # The intersection of all sets in +set_enum+.
+    #   set_enum.intersection
+    def intersection
+      set_operation(:intersection)
+    end
+
+    # Produces a SetOperand representing the disjoint union of all sets 
+    # in this enumeration.
+    #
+    # ==== Examples 
+    #
+    #   # The disjoint union of all sets in +set_enum+.
+    #   set_enum.disjoint_union
+    def disjoint_union
+      set_operation(:disjoint_union)
+    end
+
+    private
+
+    # Produces the SetOperand resulting from +operator+ applied to this
+    # operand.
+    def set_operation(operator)
+      Operation::OperationSetOperand.new(model, self, operator)
+    end
   end
-end
 
-# A module that gathers the classes and modules used by operation constaints.
-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
-        if operation == Gecode::Raw::SOT_INTER or 
-            operation == Gecode::Raw::SOT_MINUS
-          variable.must_be.subset_of enum.first.upper_bound
-        else
-          variable.must_be.subset_of enum.upper_bound_range
+  # A module that gathers the classes and modules used in operation constraints.
+  module Operation #:nodoc:
+    class OperationSetOperand < Gecode::Set::ShortCircuitEqualityOperand #:nodoc:
+      def initialize(model, enum, operator)
+        super model
+        @enum = enum
+        @operator = operator
+      end
+
+      def constrain_equal(set_operand, constrain_domain, propagation_options)
+        operation = Gecode::Util::SET_OPERATION_TYPES[@operator]
+        if constrain_domain
+          if operation == Gecode::Raw::SOT_INTER
+            set_operand.must_be.subset_of @enum.first.upper_bound
+          else
+            set_operand.must_be.subset_of @enum.upper_bound_range
+          end
         end
+        
+        Gecode::Raw::rel(@model.active_space, operation, 
+          @enum.to_set_enum.bind_array, set_operand.to_set_var.bind)
       end
-      
-      Gecode::Raw::rel(@model.active_space, operation, enum.to_set_var_array,
-        variable.bind)
     end
   end
-end
\ No newline at end of file
+end