# Class#aliases? **URL:** \ **Category:** Ruby\ **Created:** [October 11, 2007, 6:59am UTC](https://www.ruby-forum.com/t/class-aliases/116919 "2007-10-11T06:59:37Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![Giles\_B](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/848f3c/32.png) [@Giles\_B](https://www.ruby-forum.com/u/Giles_B)\ **Post date:** [October 11, 2007, 6:59am UTC](https://www.ruby-forum.com/t/class-aliases/116919/1 "2007-10-11T06:59:37Z")
Does this method exist? I think that it doesn’t, but I just thought I’d make sure. – Giles B. Blog: [http://gilesbowkett.blogspot.com](http://gilesbowkett.blogspot.com) Portfolio: [http://www.gilesgoatboy.org](http://www.gilesgoatboy.org) Tumblelog: [http://giles.tumblr.com/](http://giles.tumblr.com/) ---
**Author:** ![Giles\_B](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/848f3c/32.png) [@Giles\_B](https://www.ruby-forum.com/u/Giles_B)\ **Post date:** [October 11, 2007, 7:37am UTC](https://www.ruby-forum.com/t/class-aliases/116919/2 "2007-10-11T07:37:29Z")
Giles B. wrote: > Does this method exist? I think that it doesn’t, but I just thought > I’d make sure. > > – > Giles B. > > Blog: [http://gilesbowkett.blogspot.com](http://gilesbowkett.blogspot.com) > Portfolio: [http://www.gilesgoatboy.org](http://www.gilesgoatboy.org) > Tumblelog: [http://giles.tumblr.com/](http://giles.tumblr.com/) It is not necessary, because Classe are objects… irb(main):001:0\> class Otto irb(main):002:1\> def hi irb(main):003:2\> puts “Hi!” irb(main):004:2\> end irb(main):005:1\> end =\> nil irb(main):006:0\> Hugo = Otto =\> Otto irb(main):007:0\> Otto.new.hi Hi! =\> nil irb(main):008:0\> Hugo.new.hi Hi! =\> nil Wolfgang Nádasi-Donner ---
**Author:** ![Giles\_B](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/848f3c/32.png) [@Giles\_B](https://www.ruby-forum.com/u/Giles_B)\ **Post date:** [October 11, 2007, 9:46am UTC](https://www.ruby-forum.com/t/class-aliases/116919/3 "2007-10-11T09:46:07Z")
Giles B. wrote: > Does this method exist? I think that it doesn’t, but I just thought > I’d make sure. > > – > Giles B. > > Blog: [http://gilesbowkett.blogspot.com](http://gilesbowkett.blogspot.com) > Portfolio: [http://www.gilesgoatboy.org](http://www.gilesgoatboy.org) > Tumblelog: [http://giles.tumblr.com/](http://giles.tumblr.com/) Again - it cannot exist. The syntactic element “alias” cannot be applied to local variables, instance variables, class variables and constants - because class names are (usually) constants, they can’t have aliases. If you use normal assignment to constants for aliasing classes a simple method can be defined… class Class def aliases? Module.constants.find\_all{|c|self.equal?(const\_get(c))} end end Otto = String Hugo = String p String.aliases? # =\> [“Hugo”, “String”, “Otto”] Wolfgang Nádasi-Donner ---
**Author:** ![Giles\_B](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/848f3c/32.png) [@Giles\_B](https://www.ruby-forum.com/u/Giles_B)\ **Post date:** [October 11, 2007, 7:40am UTC](https://www.ruby-forum.com/t/class-aliases/116919/4 "2007-10-11T07:40:03Z")
Quoth Giles B.: > Does this method exist? I think that it doesn’t, but I just thought > I’d make sure. > > – > Giles B. > > Blog: [http://gilesbowkett.blogspot.com](http://gilesbowkett.blogspot.com) > Portfolio: [http://www.gilesgoatboy.org](http://www.gilesgoatboy.org) > Tumblelog: [http://giles.tumblr.com/](http://giles.tumblr.com/) Irb says no, but I’d guess you’d have already tried that. ---
**Author:** ![Giles\_B](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/848f3c/32.png) [@Giles\_B](https://www.ruby-forum.com/u/Giles_B)\ **Post date:** [October 11, 2007, 12:12pm UTC](https://www.ruby-forum.com/t/class-aliases/116919/5 "2007-10-11T12:12:52Z")
Wolfgang Nádasi-Donner wrote: > Giles B. wrote: > > > … btw - is there a difference between “alias” and “alias\_method” if applied to a method name (I don’t mean that I must use Symbols in "alias\_method)? Wolfgang Nádasi-Donner ---
**Author:** ![Giles\_B](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/848f3c/32.png) [@Giles\_B](https://www.ruby-forum.com/u/Giles_B)\ **Post date:** [October 11, 2007, 4:29pm UTC](https://www.ruby-forum.com/t/class-aliases/116919/6 "2007-10-11T16:29:10Z")
On Oct 10, 9:58 pm, “Giles B.” [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > Does this method exist? I think that it doesn’t, but I just thought > I’d make sure. Do you mean that you’d like a list of all aliases defined in a class, similar to #instance\_methods? T. ---
**Author:** ![Giles\_B](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/848f3c/32.png) [@Giles\_B](https://www.ruby-forum.com/u/Giles_B)\ **Post date:** [October 11, 2007, 4:32pm UTC](https://www.ruby-forum.com/t/class-aliases/116919/7 "2007-10-11T16:32:06Z")
On Oct 11, 2:46 am, “Wolfgang Nádasi-Donner” [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > end > > Otto = String > Hugo = String > p String.aliases? # =\> [“Hugo”, “String”, “Otto”] > > Wolfgang Nádasi-Donner > > – > Posted viahttp://www.ruby-forum.com/. It seems you and I understood the question in two different ways. Only Giles can answer this for certain, but I don’t think you’re answering the question he asked. I understood the point of Class#aliases to mean not “Are there any other constants out there that are really the same class object, and if so, what are they?” but “Are there any methods in this class that are aliases for other methods, and if so, what are the connections?” Giles, please explain. ---
**Author:** ![Giles\_B](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/848f3c/32.png) [@Giles\_B](https://www.ruby-forum.com/u/Giles_B)\ **Post date:** [October 11, 2007, 9:22pm UTC](https://www.ruby-forum.com/t/class-aliases/116919/8 "2007-10-11T21:22:30Z")
> Giles, please explain. > > – > -yossef I was skimming, and read that as “Giles, please explain yourself.” Anyway - > Do you mean that you’d like a list of all aliases defined in a class, > similar to #instance\_methods? Actually no. I was looking at an error message that expected #aliases to exist, and I thought it was weird. > I understood the point of Class#aliases to mean not “Are there any > other constants out there that are really the same class object, and > if so, what are they?” but “Are there any methods in this class that > are aliases for other methods, and if so, what are the connections?” Nope, it was just a weird error message referencing some internal code. But both these interpretations are pretty interesting. Technically, as I learned from Ryan D., you **can** actually “alias” a class, even though you can’t **alias** a class. > > Monkey = String > > =\> String > > m = Monkey.new(“asdf”) > > =\> “asdf” > > m.gsub!(/asdf/, “qwerty”) > > =\> “qwerty” – Giles B. Blog: [http://gilesbowkett.blogspot.com](http://gilesbowkett.blogspot.com) Portfolio: [http://www.gilesgoatboy.org](http://www.gilesgoatboy.org) Tumblelog: [http://giles.tumblr.com/](http://giles.tumblr.com/) ---
**Author:** ![Giles\_B](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/848f3c/32.png) [@Giles\_B](https://www.ruby-forum.com/u/Giles_B)\ **Post date:** [October 18, 2007, 1:22pm UTC](https://www.ruby-forum.com/t/class-aliases/116919/9 "2007-10-18T13:22:13Z")
Trans wrote: > On Oct 10, 9:58 pm, “Giles B.” [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > > Does this method exist? I think that it doesn’t, but I just thought > > I’d make sure. > > Do you mean that you’d like a list of all aliases defined in a class, > similar to #instance\_methods? If so, I brought this up a while back: [http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-talk/196740](http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-talk/196740) Ryan D. came up with a rather interesting solution. 🙂 One problem right off the bat, however, is that the Ruby source would need to be modified to be more stringent about using true aliases in order such a method to be accurate. Regards, Dan