channel.rb in gecoder-0.9.0

- old
+ new
@@ -1,64 +1,68 @@
-module Gecode::Constraints::BoolEnum
-  class Expression
-    # Adds a channel constraint on the variables in the enum with the specified
-    # integer variable. Beyond the common options the channel constraint can
+module Gecode::BoolEnum
+  class BoolEnumConstraintReceiver
+    # Constrains this enumeration to "channel" +integer_operand+. This 
+    # constrains the integer operand to take value i exactly when the 
+    # operand at index i in the boolean enumeration is true and the others 
+    # are false.
+    # 
+    # Beyond the common options the channel constraint can
     # also take the following option:
     #
-    # [:offset]  Specifies an offset for the integer variable. If the offset is
-    #            set to k then the integer variable takes value i+k exactly 
-    #            when the variable at index i in the boolean enumeration is true 
-    #            and the rest are false.
-    def channel(int_var, options = {})
+    # [:offset]  Specifies an offset for the integer operand. If the offset is
+    #            set to k then the integer operand takes value i+k exactly 
+    #            when the operand at index i in the boolean enumeration is 
+    #            true and the rest are false.
+    # 
+    # Neither reification nor negation is supported. The int operand
+    # and the enumeration can be interchanged.
+    #
+    # ==== Examples 
+    #
+    #   # Constrains the enumeration called +option_is_selected+ to be false 
+    #   # in the first four positions and have exactly one true operand in 
+    #   # the other. 
+    #   option_is_selected.must.channel selected_option_index 
+    #   selected_option_index.must_be > 3
+    #
+    #   # Constrains the enumeration called +option_is_selected+ to be false 
+    #   # in the first five positions and have exactly one true operand in 
+    #   # the other. 
+    #   selected_option_index.must.channel(option_is_selected, :offset => 1) 
+    #   selected_option_index.must_be > 3
+    def channel(integer_operand, options = {})
       if @params[:negate]
         raise Gecode::MissingConstraintError, 'A negated channel constraint ' + 
           'is not implemented.'
       end
       if options.has_key? :reify
         raise ArgumentError, 'The channel constraint does not support the ' + 
           'reification option.'
       end
-      unless int_var.kind_of? Gecode::FreeIntVar
-        raise TypeError, "Expected an integer variable, got #{int_var.class}."
+      unless integer_operand.respond_to? :to_int_var
+        raise TypeError, 'Expected an integer operand, got ' + 
+          "#{integer_operand.class}."
       end
       
-      @params.update(:rhs => int_var, :offset => options.delete(:offset) || 0)
-      @params.update(Gecode::Constraints::Util.decode_options(options))
+      @params.update(:rhs => integer_operand, 
+        :offset => options.delete(:offset) || 0)
+      @params.update(Gecode::Util.decode_options(options))
       @model.add_constraint Channel::ChannelConstraint.new(@model, @params)
     end
 
-    # Adds a channel constraint on the variables in the enum with the specified 
-    # set variable.
-    provide_commutivity(:channel){ |rhs, _| rhs.kind_of? Gecode::FreeSetVar }
+    # Provides commutativity with SetConstraintReceiver#channel
+    provide_commutativity(:channel){ |rhs, _| rhs.respond_to? :to_set_var }
   end
   
   # A module that gathers the classes and modules used in channel constraints
-  # involving one boolean enum and one integer variable.
+  # involving one boolean enum and one integer operand.
   module Channel #:nodoc:
-    # Describes a channel constraint that "channels" an enumeration of 
-    # boolean variables with an integer variable. This constrains the integer
-    # variable to take value i exactly when the variable at index i in the 
-    # boolean enumeration is true and the others are false.
-    # 
-    # Neither reification nor negation is supported. The int variable
-    # and the enumeration can be interchanged.
-    #
-    # == Examples
-    #
-    # # Constrains the enumeration called +option_is_selected+ to be false in the
-    # # first four positions and have exactly one true variable in the other. 
-    # option_is_selected.must.channel selected_option_index 
-    # selected_option_index.must_be > 3
-    #
-    # # Constrains the enumeration called +option_is_selected+ to be false in the
-    # # first five positions and have exactly one true variable in the other. 
-    # selected_option_index.must.channel(option_is_selected, :offset => 1) 
-    # selected_option_index.must_be > 3
-    class ChannelConstraint < Gecode::Constraints::Constraint
+    class ChannelConstraint < Gecode::Constraint #:nodoc:
       def post
         lhs, rhs, offset = @params.values_at(:lhs, :rhs, :offset)
-        Gecode::Raw::channel(@model.active_space, lhs.to_bool_var_array, 
-          rhs.bind, offset, *propagation_options)
+        Gecode::Raw::channel(@model.active_space, 
+          lhs.to_bool_enum.bind_array, rhs.to_int_var.bind, 
+          offset, *propagation_options)
       end
     end
   end
 end