as_n_tuple.cr

# with this, appropriate as_n_tuple methods are generated as used

class Array(T)
  macro method_missing(call)
    {% if call.name =~ /as_(\d+)_tuple(\?)/ %}
      def as_{{$1}}_tuple{{$2}}
        {
        {% for j in 0..($1 - 1) %}
          self[{{j}}]{{$2}},
        {% end %}
      }
      end
    {% end %}
  end
end



# OLD VERSION:

class Array(T)
  {% for i in 1..10 %}
    def as_{{i}}_tuple
      {
        {% for j in 0..(i - 1) %}
        self[{{j}}],
        {% end %}
      }
    end

    def as_{{i}}_tuple?
      {
        {% for j in 0..(i - 1) %}
        self[{{j}}]?,
        {% end %}
      }
    end
  {% end %}
end



# resulting in

class Array(T)
  def as_1_tuple
    { self[0] }
  end
  
  def as_2_tuple
    { self[0], self[1] }
  end
  
  def as_3_tuple
    { self[0], self[1], self[2] }
  end
  
  # ...
  
  def as_1_tuple?
    { self[0]? }
  end
  
  def as_2_tuple?
    { self[0]?, self[1]? }
  end
  
  def as_3_tuple?
    { self[0]?, self[1]?, self[2]? }
  end
  
  # ...

end