#* http://rosettacode.org/wiki/Pangram_checker
  Check if a string contains all letters at least once.
*#

pangram? = { sentence |
  letters = [:a :b :c :d :e :f :g :h :i :j :k :l :m
    :n :o :p :q :r :s :t :u :v :w :x :y :z]

    sentence.downcase!

    letters.reject! { l |
      sentence.include? l
    }

  letters.empty?
}

p pangram? 'The quick brown fox jumps over the lazy dog.' #Prints true
p pangram? 'Probably not a pangram.'  #Prints false

### Alternative, probably less efficient version
alt_pangram? = { sentence |
  sentence.downcase.dice.unique.select(:alpha?).length == 26
}

p alt_pangram? 'The quick brown fox jumps over the lazy dog.' #Prints true
p alt_pangram? 'Probably not a pangram.' #Prints false