class Ransack::Nodes::Condition

def extract(context, key, values)
  attributes, predicate, combinator =
    extract_values_for_condition(key, context)
  if attributes.size > 0 && predicate
    condition = self.new(context)
    condition.build(
      :a => attributes,
      :p => predicate.name,
      :m => combinator,
      :v => predicate.wants_array ? Array(values) : [values]
    )
    # TODO: Figure out what to do with multiple types of attributes,
    # if anything. Tempted to go with "garbage in, garbage out" here.
    if predicate.validate(condition.values, condition.default_type)
      condition
    else
      nil
    end
  end
end