Proof-of-concept of using `_` for Ruby class/module namespaces, with Rails-like autoloading, while avoiding the constant lookup gotchas of using `::`. Inspired by how namespaces work in Elixir (no magic; they're just module names that happen to share a prefix). This is the complexity of constant lookups in Ruby: http://cirw.in/blog/constant-look…

foo-slash-bar.rb

# Path: foo/bar.rb

class Foo_Bar
  def self.hello
    puts "Hello from Foo_Bar!"
  end
end

underscore_namespace_autoloading.rb

module UnderscoreNamespaceAutoloading
  def const_missing(name)
    parts = name.to_s.downcase.split("_")
    path = parts.join("/") + ".rb"

    if File.exist?(path)
      require_relative path
      const_get(name)
    else
      super
    end
  end
end

class Object
  singleton_class.prepend UnderscoreNamespaceAutoloading
end

Foo_Bar.hello
Foo_Baz.hello

Z_output.txt

$ ruby example.rb
Hello from Foo_Bar!
example.rb:10:in `const_missing': uninitialized constant Foo_Baz (NameError)
Did you mean?  Foo_Bar
	from example.rb:20:in `<main>'