lib/gecoder/interface/constraints/int_enum/arithmetic.rb in gecoder-0.4.0 vs lib/gecoder/interface/constraints/int_enum/arithmetic.rb in gecoder-0.5.0

@@ -15,58 +15,32 @@
 end
 
 # A module that gathers the classes and modules used by arithmetic constraints.
 module Gecode::Constraints::IntEnum::Arithmetic 
   # Describes an expression stub started with an int var enum following by #max.
-  class MaxExpressionStub < Gecode::Constraints::ExpressionStub
-    include Gecode::Constraints::LeftHandSideMethods
-    
-    private
-    
-    # Produces an expression for the lhs module.
-    def expression(params)
-      # We extract the integer and continue as if it had been specified as
-      # left hand side. This might be elegant, but it could get away with 
-      # fewer constraints at times (when only equality is used) and 
-      # propagation strength can't be specified. 
-      # TODO: cut down on the number of constraints when possible. See if 
-      # there's some neat way of getting the above remarks. 
+  class MaxExpressionStub < Gecode::Constraints::Int::CompositeStub
+    def constrain_equal(variable, params)
+      enum, strength = @params.values_at(:lhs, :strength)
+      if variable.nil?
+        variable = @model.int_var(enum.domain_range)
+      end
       
-      params.update(@params)
-      lhs = params[:lhs]
-      proxy = @model.int_var(lhs.domain_range)
-      lhs = lhs.to_int_var_array
-      
-      Gecode::Raw::max(@model.active_space, lhs, proxy.bind, 
-        Gecode::Raw::ICL_DEF)
-      Gecode::Constraints::Int::Expression.new(@model, 
-        params.update(:lhs => proxy))
+      Gecode::Raw::max(@model.active_space, enum.to_int_var_array, 
+        variable.bind, strength)
+      return variable
     end
   end
   
   # Describes an expression stub started with an int var enum following by #min.
-  class MinExpressionStub < Gecode::Constraints::ExpressionStub
-    include Gecode::Constraints::LeftHandSideMethods
-    
-    private
-    
-    # Produces an expression for the lhs module.
-    def expression(params)
-      # We extract the integer and continue as if it had been specified as
-      # left hand side. This might be elegant, but it could get away with 
-      # fewer constraints at times (when only equality is used) and 
-      # propagation strength can't be specified. 
-      # TODO: cut down on the number of constraints when possible. See if 
-      # there's some neat way of getting the above remarks. 
+  class MinExpressionStub < Gecode::Constraints::Int::CompositeStub
+    def constrain_equal(variable, params)
+      enum, strength = @params.values_at(:lhs, :strength)
+      if variable.nil?
+        variable = @model.int_var(enum.domain_range)
+      end
       
-      params.update(@params)
-      lhs = params[:lhs]
-      proxy = @model.int_var(lhs.domain_range)
-      lhs = lhs.to_int_var_array
-      
-      Gecode::Raw::min(@model.active_space, lhs, proxy.bind, 
-        Gecode::Raw::ICL_DEF)
-      Gecode::Constraints::Int::Expression.new(@model, 
-        params.update(:lhs => proxy))
+      Gecode::Raw::min(@model.active_space, enum.to_int_var_array, 
+        variable.bind, strength)
+      return variable
     end
   end
 end