stringShape

  /** Return a string that captures the generic "shape" of the original word, 
      mapping lowercase alphabetics to 'a', uppercase to 'A', digits to '1', whitespace to ' '.
      Skip more than 'maxRepetitions' of the same character class. */
  def stringShape(word:String, maxRepetitions:Int): String = {
    val sb = new StringBuffer
    var i = 0; var c = 'x'; var prevc = 'x'; var repetitions = 0
    while (i < word.length) {
      val char = word(i)
      if (Character.isUpperCase(char)) c = 'A'
      else if (Character.isLowerCase(char)) c = 'a'
      else if (Character.isDigit(char)) c = '1'
      else if (Character.isWhitespace(char)) c = ' '
      else c = char
      if (c == prevc) repetitions += 1
      else { prevc = c; repetitions = 0 }
      if (repetitions < maxRepetitions) sb.append(c)
      i += 1
    }
    sb.toString
  }