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Contents
module Gecode::Set
class SetConstraintReceiver
# Constrains this set to channel +bool_enum+. The set is constrained
# to include value i exactly when the operand at index i in the
# boolean enumeration is true.
#
# Neither reification nor negation is supported. The boolean enum and set
# can be interchanged.
#
# ==== Examples
#
# # Constrains the enumeration of boolean operands called +bools+ to at
# # least have the first and third operands set to true
# set.must_be.superset_of [0, 2]
# set.must.channel bools
#
# # An alternative way of writing the above.
# set.must_be.superset_of [0, 2]
# bools.must.channel set
def channel(bool_enum, 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 bool_enum.respond_to? :to_bool_enum
raise TypeError, 'Expected an enum of bool operands, ' +
"got #{bool_enum.class}."
end
@params.update(:rhs => bool_enum)
@params.update Gecode::Set::Util.decode_options(options)
@model.add_constraint Channel::ChannelConstraint.new(@model, @params)
end
end
# A module that gathers the classes and modules used in channel constraints
# involving one set operand and a boolean enum.
module Channel #:nodoc:
class ChannelConstraint < Gecode::Constraint #:nodoc:
def post
lhs, rhs = @params.values_at(:lhs, :rhs)
Gecode::Raw::channel(@model.active_space, rhs.to_bool_enum.bind_array,
lhs.to_set_var.bind)
end
end
end
end
Version data entries
14 entries across 14 versions & 2 rubygems