# Another Ruby language question **URL:** \ **Category:** Ruby\ **Created:** [January 27, 2007, 6:16am UTC](https://www.ruby-forum.com/t/another-ruby-language-question/83584 "2007-01-27T06:16:08Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![nevf](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/97f17d/32.png) [@nevf](https://www.ruby-forum.com/u/nevf)\ **Post date:** [January 27, 2007, 6:16am UTC](https://www.ruby-forum.com/t/another-ruby-language-question/83584/1 "2007-01-27T06:16:08Z")
Following from yesterday I have a few more Ruby questions. Can someone please explain what ‘self’ does in the following: module Mod1 def self.a\_method puts ‘a’ end def b\_method puts ‘b’ end end If self isn’t specificed I’m unable to call the method. ex. Mod1::b\_method fails. I’ve scoured on-line docs about module and come up empty. Next. What does ‘/upload’ mean in: class Upload \< R ‘/upload’ This is from: > **[O'Reilly Media - Technology and Business Training](https://www.oreilly.com)** > > Gain technology and business knowledge and hone your skills with learning resources created and curated by O'Reilly's experts: live online training, video, books, our platform has content from 200+ of the world's best publishers. Thanks. * * * Neville F., [http://www.getsoft.com](http://www.getsoft.com) [http://www.surfulater.com](http://www.surfulater.com) ---
**Author:** ![nevf](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/97f17d/32.png) [@nevf](https://www.ruby-forum.com/u/nevf)\ **Post date:** [January 27, 2007, 6:43am UTC](https://www.ruby-forum.com/t/another-ruby-language-question/83584/2 "2007-01-27T06:43:53Z")
On 1/27/07, Neville F. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > ``` > puts 'b' > > ``` > > end > end > > If self isn’t specificed I’m unable to call the method. ex. > Mod1::b\_method fails. So in this particular case, ‘self’ here refers to the Module called Mod1. Your code defines a method (a\_method) on the module itself which allows you to call it with the :: syntax. The other method (b\_method) is merely a method defined inside the module. In this case the module is acting as a namespace. If you ‘include’ this module somewhere in your code you’ll be adding the b\_method to that place (scope?) (disclaimer: I’m still learning ruby myself, so that may not be the best answer ever, but it is how I understand it… And knowing these guys these days I’ll be corrected if I’m wrong, mere moments from now.) > Next. What does ‘/upload’ mean in: > class Upload \< R ‘/upload’ > This is from: > [O'Reilly Media - Technology and Business Training](http://www.oreillynet.com/ruby/blog/2007/01/the_joy_of_rolling_your_own_wi.html) Right here you’re fishing in \_why territory (specifically the camping framework) where things are way over my head, someone else will have to help you there. hth, -Harold ---
**Author:** ![nevf](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/97f17d/32.png) [@nevf](https://www.ruby-forum.com/u/nevf)\ **Post date:** [January 27, 2007, 7:07am UTC](https://www.ruby-forum.com/t/another-ruby-language-question/83584/3 "2007-01-27T07:07:21Z")
Harold H. wrote: > On 1/27/07, Neville F. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > > ``` > > puts 'b' > > > > ``` > > > > end > > end > > > > If self isn’t specificed I’m unable to call the method. ex. > > Mod1::b\_method fails. > > So in this particular case, ‘self’ here refers to the Module called > Mod1. Your code defines a method (a\_method) on the module itself which > allows you to call it with the :: syntax. > > The other method (b\_method) is merely a method defined inside the > module. In this case the module is acting as a namespace. If you > ‘include’ this module somewhere in your code you’ll be adding the > b\_method to that place (scope?) > > (disclaimer: I’m still learning ruby myself, so that may not be the > best answer ever, but it is how I understand it… And knowing these > guys these days I’ll be corrected if I’m wrong, mere moments from > now.) Harold, Thanks for that. I figured I understood the use of self, but assumed it was redundant and therefore I couldn’t see the difference between a\_method and b\_method. Now I get it. In my C++ world we don’t qualify methods like this. * * * Neville F., [http://www.getsoft.com](http://www.getsoft.com) [http://www.surfulater.com](http://www.surfulater.com) ---
**Author:** ![nevf](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/97f17d/32.png) [@nevf](https://www.ruby-forum.com/u/nevf)\ **Post date:** [January 27, 2007, 7:25am UTC](https://www.ruby-forum.com/t/another-ruby-language-question/83584/4 "2007-01-27T07:25:55Z")
On 1/27/07, Neville F. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > was redundant and therefore I couldn’t see the difference between > a\_method and b\_method. Now I get it. In my C++ world we don’t qualify > methods like this. No problemo. In comparison to C++, your a\_method is (kinda sorta) like a static method, but not really, but kindof because you can use the :: syntax to call it. b\_method is more like a method belonging to a class which you’re inheriting. The instances of your new class can call b\_method (assuming you’ve included Mod1) … Ruby only supports single inheritance directly, but you can emulate multiple inheritance like this by just including multiple modules into your class… I believe the rubyists like to call this mixing-in… hth, -Harold ---
**Author:** ![nevf](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/97f17d/32.png) [@nevf](https://www.ruby-forum.com/u/nevf)\ **Post date:** [January 27, 2007, 7:27am UTC](https://www.ruby-forum.com/t/another-ruby-language-question/83584/5 "2007-01-27T07:27:16Z")
So I assume that: module Mod1 def self.a\_method puts ‘a’ end end is identical to: module Mod1 def Mod1.a\_method puts ‘a’ end end * * * Neville F., [http://www.getsoft.com](http://www.getsoft.com) [http://www.surfulater.com](http://www.surfulater.com) ---
**Author:** ![nevf](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/97f17d/32.png) [@nevf](https://www.ruby-forum.com/u/nevf)\ **Post date:** [January 27, 2007, 7:32am UTC](https://www.ruby-forum.com/t/another-ruby-language-question/83584/6 "2007-01-27T07:32:56Z")
On 1/27/07, Neville F. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > module Mod1 > def Mod1.a\_method > puts ‘a’ > end > end indeed. (apologies to anyone not reading this in a threaded fashion for the extremely short reply.) -Harold ---
**Author:** ![nevf](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/97f17d/32.png) [@nevf](https://www.ruby-forum.com/u/nevf)\ **Post date:** [January 27, 2007, 10:00pm UTC](https://www.ruby-forum.com/t/another-ruby-language-question/83584/7 "2007-01-27T22:00:29Z")
On 1/26/07, Neville F. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > ``` > puts 'b' > > ``` > > end > end > > If self isn’t specificed I’m unable to call the method. ex. > Mod1::b\_method fails. > > I’ve scoured on-line docs about module and come up empty. I see people already helped you with this one > Next. What does ‘/upload’ mean in: > class Upload \< R ‘/upload’ This is the beginning of a controller definition in the Camping microframework. The class is “inheriting” from the method R() which takes a regex argument of the route to bind to. The R() method then adds some meta-info to the runtime, and returns an anonymous class that Upload actually inherits from.