class Thor::Runner

def display_klasses(with_modules=false, show_internal=false, klasses=Thor::Base.subclasses)
  klasses -= [Thor, Thor::Runner, Thor::Group] unless show_internal
  raise Error, "No Thor tasks available" if klasses.empty?
  show_modules if with_modules && !thor_yaml.empty?
  list = Hash.new { |h,k| h[k] = [] }
  groups = klasses.select { |k| k.ancestors.include?(Thor::Group) }
  # Get classes which inherit from Thor
  (klasses - groups).each { |k| list[k.namespace.split(":").first] += k.printable_tasks(false) }
  # Get classes which inherit from Thor::Base
  groups.map! { |k| k.printable_tasks(false).first }
  list["root"] = groups
  # Order namespaces with default coming first
  list = list.sort{ |a,b| a[0].sub(/^default/, '') <=> b[0].sub(/^default/, '') }
  list.each { |n, tasks| display_tasks(n, tasks) unless tasks.empty? }
end