David Vollbracht

Here’s a hack I cooked up some time ago for situations where you want an enumerable with a minimum length. It decorates an existing enum instance (an object supporting the each method) to contain a minimum number of objects, returning a “filler” object if the end of the wrapped enum is reached before hitting the minimum length. It’s probably easier understood through a simple code example.

  MinLengthEnum.new(4,[1,2],"filler").to_a #=> [1, 2, "filler", "filler"]

And then the implementation, which is quite simple

  class MinLengthEnum
    include Enumerable

    def initialize(length,enum,filler = nil)
      @length = length
      @enum   = enum
      @filler = filler
    end

    def each
      filler = [@filler] * @length
      @enum.each {|o| yield o; filler.shift}
      filler.each {|o| yield o}
    end
  end

There you have it. Nothing special, but something. Have a great day!