A module may or may not have a name.
module M; end M.name # => "M" m = Module.new m.name # => ""
A module gets a name when it is first assigned to a constant. Either via the module or class keyword or by an explicit assignment:
m = Module.new # creates an anonymous module M = m # => m gets a name here as a side-effect m.name # => "M"
# File activesupport/lib/active_support/core_ext/module/anonymous.rb, line 19 def anonymous? # Uses blank? because the name of an anonymous class is an empty # string in 1.8, and nil in 1.9. name.blank? end