Ruby: How to make a public static method?

Your given example is working very well

class Ask
  def self.make_permalink(phrase)
    phrase.strip.downcase.gsub! /\ +/, '-'
  end
end

Ask.make_permalink("make a slug out of this line")

I tried in 1.8.7 and also in 1.9.3 Do you have a typo in you original script?

All the best

There is one more syntax which is has the benefit that you can add more static methods

class TestClass

  # all methods in this block are static
  class << self
    def first_method
      # body omitted
    end

    def second_method_etc
      # body omitted
    end
  end

  # more typing because of the self. but much clear that the method is static
  def self.first_method
    # body omitted
  end

  def self.second_method_etc
    # body omitted
  end
end

Here's my copy/paste of your code into IRB. Seems to work fine.

$ irb
1.8.7 :001 > class Ask
1.8.7 :002?>   
1.8.7 :003 >   def self.make_permalink(phrase)
1.8.7 :004?>     phrase.strip.downcase.gsub! /\ +/, '-'
1.8.7 :005?>   end
1.8.7 :006?>   
1.8.7 :007 > end
 => nil 
1.8.7 :008 > Ask.make_permalink("make a slug out of this line")
 => "make-a-slug-out-of-this-line"

Seems to work. Test it out in your irb as well, and see what results you're getting. I'm using 1.8.7 in this example, but I also tried it in a Ruby 1.9.3 session and it worked identically.

Are you using MRI as your Ruby implementation (not that I think that should make a difference in this case)?

In irb make a call to Ask.public_methods and make sure your method name is in the list. For example:

1.8.7 :008 > Ask.public_methods
 => [:make_permalink, :allocate, :new, :superclass, :freeze, :===, 
     ...etc, etc.] 

Since you also marked this as a ruby-on-rails question, if you want to troubleshoot the actual model in your app, you can of course use the rails console: (bundle exec rails c) and verify the publicness of the method in question.