just_hacking.rb

def ham_dist(word)
  a = SHA1.hexdigest(word).to_i(16)
  b = "6cac827bae250971a8b1fb6e2a96676f7a077b60".to_i(16)
  (a ^ b).to_s(2).split('').inject(0) {|sum,i| sum + i.to_i }
end

def permute(sentence)
  non_space_chars = sentence.scan(/\S/).count
  (0...(2**non_space_chars)).each do |mask|
    yield apply_mask(sentence,mask)
  end
end

def apply_mask(sentence,mask)
  i = 0
  sentence.gsub(/\S/) do |char|
    char = char.swapcase if mask[i] == 1 
    i += 1
    char
  end
end

def yield_all_endings(original)
  (0...(2**5)).each do |mask|
    'a'.upto('zzzzz') do |ending|
      # yield something  
    end
  end
end