#!/usr/bin/env ruby -wKU
letters_only = /^[a-z]+$/i
phone_number = /^\(\d{3}\)\s?\d{3}-\d{4}$/
numbers_below_18 = /^(([0-1]?[0-8])|(-\d*))$/
html_tag = /^<([A-Z]*)>(.*)<\/\1>$/

print "Input text: "
input = gets.strip
until input == "quit" do
  puts case input
         when letters_only then "Letters"
         when phone_number then "Phone Number"
         when numbers_below_18 then "Number below 18"
         when html_tag then "HTML tag"
         else "No matches"
       end
  print "Input text: "
  input = gets.strip
end