support for multi range (multi_period?)

[tomasc]

I have implemented very rudimentary suport for multi range type in my app. Some example snippets below. I start to use these types of ranges more and more, as they proved very useful.

It would be great if torque-postgresql would have support for this. I can prepare a PR, but would need some guidance with how to implement this in the current gem's architecture.

# SQL
range_agg(tstzrange(starttime, endtime, '[]')) AS multi_period

# MultiPeriod.value(self[:multi_period]) => converts column to Array of Range objects
class MultiPeriod
  extend Dry::Initializer

  param :multi_period, type: Types::Array.of(Types.Instance(Range)) | Types::Coercible::String

  def self.value(...)
    new(...).value
  end

  def value
    return multi_period if multi_period.is_a?(Array)

    json_value.map do |from, to|
      (Time.zone.parse(from).to_datetime..Time.zone.parse(to).to_datetime)
    end.sort_by(&:first)
  end

  private
    def json_value
      JSON.parse("[#{multi_period[1..-2]}]")
    end
end

scope :order_by_lower, -> (dir = :asc) { order(Arel.sql("lower(multi_period) #{dir}")) }
scope :order_by_upper, -> (dir = :asc) { order(Arel.sql("upper(multi_period) #{dir}")) }

scope :multi_period_overlapping, -> (from, to) { where("multi_period && ?", Arel.sql("{[#{from},#{to}]}")) }

[crashtech]

Hey @tomasc, sorry for taking so long to reply. I've been quite engaged in my current project!
I'll be checking this tomorrow. My first instinct is that AR already handles arrays of types as a modifier. That said, what might need to be provided is a way to alias or give the proper name for them (which I think it's possible with a few lines).

[tomasc]

Thank you @crashtech , that would be lovely!