all mutations

kmer_find.rb

class Array
  def expand(master, mut)
    collection = []
    each do |str|
      c = str.count('.') 
      case 
      when c < mut 
        collection << str + master[str.length]
        collection << str + '.'
      when c == mut 
        collection << str + master[str.length]
      end
    end
    collection
  end
  def mutagenize_frags(master, mut, len=master.length)
    var = self.dup
    while var.first.length < len do
      var = var.send(:expand, *[master, mut])
    end
    var.sort
  end
end

class String
  def mutagenize_frags(mut,len=self.length)
    [''].mutagenize_frags(self,mut,len)
  end
end
puts "ABCDEF".mutagenize_frags(5)