class Tynn
  # Adds extra matchers to Tynn.
  #
  # ```
  # require "tynn"
  # require "tynn/matchers"
  #
  # Tynn.helpers(Tynn::Matchers)
  # ```
  #
  module Matchers
    # A catch-all matcher.
    #
    # ```
    # Tynn.define do
    #   authenticated? do
    #     # ...
    #   end
    #
    #   default do # on true
    #     # ...
    #   end
    # end
    # ```
    #
    # :call-seq: default(&block)
    #
    def default
      yield

      halt(res.finish)
    end

    # Match if the given `key` is present in `req.params`.
    #
    # ```
    # Tynn.define do
    #   param(:user) do |params|
    #     user = User.create(params)
    #
    #     # ...
    #   end
    #
    #   default do
    #     res.write("missing user param")
    #   end
    # end
    # ```
    #
    # :call-seq: param(key, &block)
    #
    def param(key)
      if (v = req[key]) && !v.empty?
        yield(v)

        halt(res.finish)
      end
    end
  end
end