dry-types => Mutable Struct

mutable.rb

module Dry
  module Types
    class Struct
      # A variation on dry-types Struct that includes property writers
      class Mutable < Struct
        constructor_type :schema

        def self.attributes(new_schema)
          super
          new_schema.keys.each do |key|
            define_method("#{key}=") do |value|
              # Courtesy of Andy Holland in the dry-rb gitter chat
              instance_variable_set("@#{key}", self.class.schema[key][value])
            end
          end
          self
        end
      end
    end
  end
end