split

# File activesupport/lib/active_support/core_ext/array/grouping.rb, line 91
  def split(value = nil)
    if block_given?
      inject([[]]) do |results, element|
        if yield(element)
          results << []
        else
          results.last << element
        end

        results
      end
    else
      results, arr = [[]], self.dup
      until arr.empty?
        if (idx = arr.index(value))
          results.last.concat(arr.shift(idx))
          arr.shift
          results << []
        else
          results.last.concat(arr.shift(arr.size))
        end
      end
      results
    end
  end