Crystal Proc#curry method (implemented with macros)

curry.cr

struct Proc(*T, R)
  def curry
    {% begin %}
      {% for i in 0...T.size %}
        ->(arg_{{i}} : {{T[i]}}) {
      {% end %}
          self.call(
            {% for i in 0...T.size %}
              arg_{{i}},
            {% end %}
          )
      {% for i in 0...T.size %}
        }
      {% end %}
    {% end %}
  end
end