module Rails::Generators

def self.help(command = 'generate')
  lookup!
  namespaces = subclasses.map{ |k| k.namespace }
  namespaces.sort!
  groups = Hash.new { |h,k| h[k] = [] }
  namespaces.each do |namespace|
    base = namespace.split(':').first
    groups[base] << namespace
  end
  puts "Usage: rails #{command} GENERATOR [args] [options]"
  puts
  puts "General options:"
  puts "  -h, [--help]     # Print generator's options and usage"
  puts "  -p, [--pretend]  # Run but do not make any changes"
  puts "  -f, [--force]    # Overwrite files that already exist"
  puts "  -s, [--skip]     # Skip files that already exist"
  puts "  -q, [--quiet]    # Suppress status output"
  puts
  puts "Please choose a generator below."
  puts
  # Print Rails defaults first.
  rails = groups.delete("rails")
  rails.map! { |n| n.sub(/^rails:/, '') }
  rails.delete("app")
  print_list("rails", rails)
  hidden_namespaces.each {|n| groups.delete(n.to_s) }
  groups.sort.each { |b, n| print_list(b, n) }
end