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method_missing_respond_to_missing

🕵️ Advanced method_missing with respond_to_missing?​

Override method_missing judiciously to delegate or synthesize methods, but pair it with respond_to_missing? so introspection (and Rails) works correctly.

class Config
  def initialize(settings)
    @settings = settings
  end

  def method_missing(name, *args, &block)
    key = name.to_s.chomp("?")
    return @settings[key.to_sym] if name.to_s.end_with?('?')
    super
  end

  def respond_to_missing?(name, include_private = false)
    name.to_s.end_with?('?') || super
  end
end

cfg = Config.new(debug: true)
p cfg.debug?  # => true
p cfg.respond_to?(:debug?) # => true