A solution to the Ruby Quiz: http://rubyquiz.com/quiz121.html

mores_code.rb

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# A solution to the Ruby Quiz: http://rubyquiz.com/quiz121.html #
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INPUT = "...---..-....-"    # Eugenia or Sofia
HELLO = "......-...-..---"  # Hello
OK    = "----.-"            # Ok or Toa

class Morse
  LETTERS_REPRESENTATION = {
    "A" => ".-"  , "N" => "-."  ,
    "B" => "-...", "O" => "---" ,
    "C" => "-.-.", "P" => ".--.",
    "D" => "-.." , "Q" => "--.-",
    "E" => "."   , "R" => ".-." ,
    "F" => "..-.", "S" => "..." ,
    "G" => "--." , "T" => "-"   ,
    "H" => "....", "U" => "..-" ,
    "I" => ".."  , "V" => "...-",
    "J" => ".---", "W" => ".--" ,
    "K" => "-.-" , "X" => "-..-",
    "L" => ".-..", "Y" => "-.--",
    "M" => "--"  , "Z" => "--.."
  }
  MORSE_TO_LETTERS = LETTERS_REPRESENTATION.invert

  # Returns an array of all possible decoded permutations of the input morse code
  def self.words(code)
    words = []
    # Decode the first letter (which might be 1-4 charecters long)
    # and recursively parse the rest of the input
    possible_first_letters(code) do |letter, length|
      remeaning = words(code[length+1..-1])
      possible_words(letter, remeaning) do |word|
        words.push word
      end
    end
    words
  end

private

  def self.possible_first_letters(input)
    max_letter_length = [3, input.length-1].min
    for length in 0..max_letter_length do
      letter = MORSE_TO_LETTERS[input[0..length]]
      yield letter, length if letter
    end
  end

  def self.possible_words(first_letter, remeaning)
    if remeaning.empty?
      yield first_letter
    else
      remeaning.each do |letters| 
        yield first_letter + letters
      end
    end
  end
end

class Dictionary
  DICTIONARY_FILE = '/usr/share/dict/words'

  def self.preload
    # Build a hash of dictionary words from the dictionary file
    @@dict ||= Hash[File.readlines(DICTIONARY_FILE).map {|word| [word.strip.downcase, true]}]
  end

  def self.include?(word)
    # If the dictioary was not initialized search the file
    return open(DICTIONARY_FILE) { |f| f.grep(/^#{word.downcase}$/i) }.any? unless @@dict
    @@dict[word.downcase]
  end
end

class BoredClerk
  def initialize
    puts "I am busy! Please wait while I read a bit from the dictionary... Ohh how I love to learn new words!"
    Dictionary.preload
    puts "Yes, how may I help you?"
  end

  def read_morse(code)
    repsond words(code)
  end

private

  def repsond(words)
    if words.empty?
      puts "This Gibberish doesn't make any sense!"
    elsif words.length == 1
      puts "Your code says '#{words.first}'"
    else
      puts "Your code might mean #{words.join(' or ')}."
    end
  end

  def words(code)
    Morse.words(code).map { |word| word if Dictionary.include? word }.compact
  end
end