class Gecode::Bool::BoolConstraintReceiver

BoolConstraintReceiver contains all constraints that can be placed on a BoolOperand.

Constraints are placed by calling Gecode::Operand#must (or any other of the variations defined in Operand), which produces a BoolConstraintReceiver from which the desired constraint can be used.

Each constraint accepts a number of options. See ConstraintReceiver for more information.

Examples ¶ ↑

Constrains bool_operand to be true using #true:

bool_operand.must_be.true

Constrains bool_operand1 AND bool_operand2 to be true using the BoolOperand#& property and #true:

(bool_operand1 & bool_operand2).must_be.true

Constrains the conjunction of all boolean operands in bool_enum to not imply bool_operand using the BoolEnumOperand#conjunction property and #imply:

bool_enum.conjunction.must_not.imply bool_operand

The same as above, but specifying that strength :domain should be used and that the constraint should be reified with bool_operand2:

bool_enum.conjunction.must_not.imply(bool_operand, :strength => :domain, :reify => bool_operand2)

Public Instance Methods

==(bool_op, options = {}) click to toggle source

Constrains the boolean operand to be equal to bool_op. Any of ==, equal and equal_to may be used for equality.

Examples ¶ ↑

# +b1+ and +b2+ must equal +b1+ or +b2+.
(b1 & b2).must == (b1 | b2)

# +b1+ and +b2+ must not equal +b3+. We reify it with +bool+ and select 
# the strength +domain+.
(b1 & b2).must_not.equal(b3, :reify => bool, :select => :domain)

# File doc/tmp/rdoc_dev/gecoder/interface/constraints/bool/boolean.rb, line 72
def ==(bool_op, options = {})
  unless bool_op.respond_to? :to_minimodel_bool_expr
    bool_op = ExpressionNode.new(bool_op, @model)
  end
  @params.update Gecode::Util.decode_options(options)
  @params.update(:lhs => @params[:lhs], :rhs => bool_op)
  @model.add_constraint BooleanConstraint.new(@model, @params)
end

false(options = {}) click to toggle source

Constrains the boolean operand to be false.

Examples ¶ ↑

# +b1+ and +b2+ must be false.
(b1 & b2).must_be.false

# (+b1+ implies +b2+) and (+b3+ implies +b2+) must be false.
((b1.implies b2) & (b3.implies b2)).must_be.false

# +b1+ and +b2+ must be false. We reify it with +bool+ and select the
# strength +domain+.
(b1 & b2).must_be.false(:reify => bool, :strength => :domain)

# File doc/tmp/rdoc_dev/gecoder/interface/constraints/bool/boolean.rb, line 130
def false(options = {})
  @params[:negate] = !@params[:negate]
  self.true(options)
end

imply(bool_op, options = {}) click to toggle source

Constrains the boolean operand to imply bool_op.

Examples ¶ ↑

# +b1+ must imply +b2+
b1.must.imply b2

# +b1+ and +b2+ must not imply +b3+. We reify it with +bool+ and select
# +domain+ as strength.
(b1 & b2).must_not.imply(b3, :reify => bool, :strength => :domain)

# File doc/tmp/rdoc_dev/gecoder/interface/constraints/bool/boolean.rb, line 92
def imply(bool_op, options = {})
  @params.update Gecode::Util.decode_options(options)
  @params.update(:lhs => @params[:lhs].implies(bool_op), :rhs => true)
  @model.add_constraint BooleanConstraint.new(@model, @params)
end

true(options = {}) click to toggle source

Constrains the boolean operand to be true.

Examples ¶ ↑

# +b1+ and +b2+ must be true.
(b1 & b2).must_be.true

# (+b1+ implies +b2+) and (+b3+ implies +b2+) must be true.
((b1.implies b2) & (b3.implies b2)).must_be.true

# +b1+ and +b2+ must be true. We reify it with +bool+ and select the
# strength +domain+.
(b1 & b2).must_be.true(:reify => bool, :strength => :domain)

# File doc/tmp/rdoc_dev/gecoder/interface/constraints/bool/boolean.rb, line 111
def true(options = {})
  @params.update Gecode::Util.decode_options(options)
  @model.add_constraint BooleanConstraint.new(@model, 
    @params.update(:rhs => true))
end

Public Class Methods

new(model, params) click to toggle source

Raises TypeError unless the left hand side is an bool operand.

Calls superclass method Gecode::ConstraintReceiver.new

# File doc/tmp/rdoc_dev/gecoder/interface/constraints/bool_var_constraints.rb, line 86
def initialize(model, params) 
  super

  unless params[:lhs].respond_to? :to_bool_var
    raise TypeError, 'Must have bool operand as left hand side.'
  end
end