class Gecode::Set::ShortCircuitRelationsOperand

An operand that short circuits set non-negated and non-reified versions of the relation constraints.

Attributes

model[R]

Public Instance Methods

construct_receiver(params) click to toggle source

# File doc/tmp/rdoc_dev/gecoder/interface/constraints/set_var_constraints.rb, line 127
def construct_receiver(params)
  params.update(:lhs => self)
  receiver = SetConstraintReceiver.new(@model, params)
  op = self
  receiver.instance_eval{ @short_circuit = op }
  class <<receiver
    Gecode::Util::SET_RELATION_TYPES.keys.each do |comp|
      eval <<-end_code
        alias_method :alias_#{comp.to_i}_without_short_circuit, :#{comp}
        def #{comp}(operand, options = {})
          if !@params[:negate] && !options.has_key?(:reify) && 
              (operand.respond_to?(:to_set_var) or 
              Gecode::Util::constant_set?(operand))
            # Short circuit the constraint.
            @params.update Gecode::Set::Util.decode_options(options)
            @model.add_constraint(
              @short_circuit.relation_constraint(
                :#{comp}, operand, @params))
          else
            alias_#{comp.to_i}_without_short_circuit(operand, options)
          end
        end
      end_code
    end
    alias_comparison_methods
  end

  return receiver
end

relation_constraint(relation, set_operand_or_constant_set, params) click to toggle source

Returns a constraint that constrains this operand to have relation relation to set_operand_or_constant_set, which is either a set operand or a constant set, given the specified hash params of parameters. The constraints are never negated nor reified.

# File doc/tmp/rdoc_dev/gecoder/interface/constraints/set_var_constraints.rb, line 169
def relation_constraint(relation, set_operand_or_constant_set, params)
  raise NotImplementedError, 'Abstract method has not been implemented.'
end

to_set_var() click to toggle source

# File doc/tmp/rdoc_dev/gecoder/interface/constraints/set_var_constraints.rb, line 157
def to_set_var
  variable = model.set_var
  params = {:lhs => self}
  params.update Gecode::Set::Util.decode_options({})
  model.add_constraint relation_constraint(:==, variable, params)
  return variable
end

Public Class Methods

new(model) click to toggle source

# File doc/tmp/rdoc_dev/gecoder/interface/constraints/set_var_constraints.rb, line 123
def initialize(model)
  @model = model
end