From: Logan Capaldo <logancapaldo@...>
Date: 2006-09-05T21:49:33+09:00
Subject: Re: Enum


On Sep 5, 2006, at 5:24 AM, Ohad Lutzky wrote:

> I want an enum of sorts in my Rails application.
>
> I have a Project object, which has four possible status settings, as
> indicated here:
>
>   class Project < ActiveRecord:Base
>     ...
>     class << self
>       def statuses
>         [ 'Hidden', 'Available', 'In progress', 'Complete' ]
>       end
>     end
>     ...
>   end
>
> These are not expected to change, so hardcoding is preferable. Of
> course, there is a 'status' column in the project table, so rails
> creates a 'status' accessor.
>
> However, later in the code I will want to check the status myself. For
> example, 'Complete' projects won't be shown in the same place as
> 'Available' ones, and 'In progress' and 'Hidden' projects won't be  
> shown
> at all (not sure about In progress ATM though, so I want to keep it
> flexible). Now, it would be pretty ugly checking
>
>   if a_project.status == 2 # Project is in progress
>
> [snip]
> Any other ideas for elegance?
>

I usually do:

class A
   [ 'Hidden', 'Available', 'Etc' ].each do |s|
     const_set(s, k = Object.new)
     def k.to_s
       "A::#{s}"
     end
     k.freeze
   end
end

Then you can say if obj.status  == A::Available, etc.


>
> -- 
> Posted via http://www.ruby-forum.com/.
>