获取类/模块名称

Question

Is there a better way to get class/module name viz, C from A::B::C , B from A::B::C , and A From A::B::C . The following code uses string and split to get "Stegosaurus" from Cowsay::Character::Stegosaurus , How to do away with string and split?

require 'cowsay'
x = Cowsay.random_character().class
x.name.split("::")[2]
require 'cowsay'
true
x = Cowsay.random_character().class
Cowsay::Character::Stegosaurus
x.name.split("::")[2]
"Stegosaurus"

Answer 1

I don't think there's anything for handling this in core/standard library.

As an alternative to custom written methods there is always activesupport :

require 'active_support/core_ext/string/inflections'
Cowsay::Character::Stegosaurus.name.demodulize
#=> "Stegosaurus"
Cowsay::Character::Stegosaurus.name.deconstantize
#=> "Cowsay::Character"

These methods are implemented as follows:

def demodulize(path)
  path = path.to_s
  if i = path.rindex('::')
    path[(i+2)..-1]
  else
    path
  end
end

def deconstantize(path)
  path.to_s[0, path.rindex('::') || 0] # implementation based on the one in facets' Module#spacename
end

Take a look into docs if interested in more methods.

As to

A From A::B::C

If you'd require the whole activesupport , you'd get bunch of Module methods, including parent :

require 'active_support'
Cowsay::Character::Stegosaurus.parent
#=> Cowsay

If you're not going to use it extensively, I recommend to just grab the needed methods from activesupport and put it into some helper, because loading it whole might be an overkill.