Class: Gecode::Set::ShortCircuitEqualityOperand

Inherits:
Object
  • Object
show all
Includes:
SetOperand
Defined in:
lib/gecoder/interface/constraints/set_var_constraints.rb

Overview

An operand that short circuits set equality.

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from SetOperand

#disjoint_union, #elements, #intersection, #method_missing, #minus, #size, #union

Methods included from Operand

#must, #must_not

Constructor Details

#initialize(model) ⇒ ShortCircuitEqualityOperand

Returns a new instance of ShortCircuitEqualityOperand.



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# File 'lib/gecoder/interface/constraints/set_var_constraints.rb', line 64

def initialize(model)
  @model = model
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method in the class Gecode::Set::SetOperand

Instance Attribute Details

#model ⇒ Object (readonly)

Returns the value of attribute model.



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# File 'lib/gecoder/interface/constraints/set_var_constraints.rb', line 62

def model
  @model
end

Instance Method Details

#construct_receiver(params) ⇒ Object 



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# File 'lib/gecoder/interface/constraints/set_var_constraints.rb', line 68

def construct_receiver(params)
  params.update(:lhs => self)
  receiver = SetConstraintReceiver.new(@model, params)
  op = self
  receiver.instance_eval{ @short_circuit = op }
  class <<receiver
    alias_method :equality_without_short_circuit, :==
    def ==(operand, options = {})
      if !@params[:negate] and !options.has_key?(:reify) and 
          operand.respond_to? :to_set_var
        # Short circuit the constraint.
        @params.update Gecode::Util.decode_options(options)
        @model.add_constraint(Gecode::BlockConstraint.new(
            @model, @params) do
          @short_circuit.constrain_equal(operand, false,
            @params.values_at(:strength, :kind))
        end)
      else
        equality_without_short_circuit(operand, options)
      end
    end
    alias_comparison_methods
  end

  return receiver
end

#to_set_var ⇒ Object 



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# File 'lib/gecoder/interface/constraints/set_var_constraints.rb', line 95

def to_set_var
  variable = model.set_var
  options = 
    Gecode::Set::Util.decode_options(
      {}).values_at(:strength, :kind)
  model.add_interaction do
    constrain_equal(variable, true, options)
  end
  return variable
end