Rails - Jan 2008 - using same validation-set in more than one class

hello,
lets describe my situation: i have two classes which have a lot same
validations defined ... to stay DRY i want to put them in one place and
use it within both ActiveRecord classes.

- i think subclassing is not possible because both classes are AR of
different tables

- tried to include a module but this didnt work either:

module CustomExtensions
 validates_length_of :a, :in => 1..10
 validates_length_of :b, :in => 1..20
end

class A < AR::Base
  include CustomExtensions
end

thx for help!
-- 
Posted via http://www.ruby-forum.com/.

--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Talk" group.
To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en
-~----------~----~----~----~------~----~------~--~---

On 22 Jan 2008, at 09:16, Michal Gabrukiewicz wrote:
>
> hello,
> lets describe my situation: i have two classes which have a lot same
> validations defined ... to stay DRY i want to put them in one place  
> and
> use it within both ActiveRecord classes.
>
> - i think subclassing is not possible because both classes are AR of
> different tables
>
> - tried to include a module but this didnt work either:
>
> module CustomExtensions
> validates_length_of :a, :in => 1..10
> validates_length_of :b, :in => 1..20
> end
>
> class A < AR::Base
>  include CustomExtensions
> end
>
nearly there!

module CommonStuff
   def self.included(base)
     base.instance_eval do
       validates_length_of :a, :in => 1..10
       validates_length_of :b, :in => 1..20
     end
   end
   ...
end

class A < AR::Base
   include CommonStuff
end
> thx for help!
> -- 
> Posted via http://www.ruby-forum.com/.
>
> >

--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Talk" group.
To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en
-~----------~----~----~----~------~----~------~--~---

hey thx for the quick reply .. it worked!
i am just wondering why its "instance_eval" and not
"class_eval"...
should the validations not be applied to the whole class?
> nearly there!
> 
> module CommonStuff
>    def self.included(base)
>      base.instance_eval do
>        validates_length_of :a, :in => 1..10
>        validates_length_of :b, :in => 1..20
>      end
>    end
>    ...
> end
> 
> class A < AR::Base
>    include CommonStuff
> end
-- 
Posted via http://www.ruby-forum.com/.

--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Talk" group.
To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en
-~----------~----~----~----~------~----~------~--~---

On 22 Jan 2008, at 09:44, Michal Gabrukiewicz wrote:
>
> hey thx for the quick reply .. it worked!
> i am just wondering why its "instance_eval" and not
"class_eval"...
> should the validations not be applied to the whole class?
>
In this particular case it doesn''t make any difference. instance_eval  
means that self will be the base class (ie A) when the validates_*  
calls are made. module_eval (which is the same as class eval) would do  
the same thing (it would be different if we were defining methods  
inside the eval block, but we''re not)

Fred
>> nearly there!
>>
>> module CommonStuff
>>   def self.included(base)
>>     base.instance_eval do
>>       validates_length_of :a, :in => 1..10
>>       validates_length_of :b, :in => 1..20
>>     end
>>   end
>>   ...
>> end
>>
>> class A < AR::Base
>>   include CommonStuff
>> end
>
> -- 
> Posted via http://www.ruby-forum.com/.
>
> >

--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Talk" group.
To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en
-~----------~----~----~----~------~----~------~--~---

Frederick Cheung wrote:
> In this particular case it doesn''t make any difference.
instance_eval
> means that self will be the base class (ie A) when the validates_*
> calls are made. module_eval (which is the same as class eval) would do
> the same thing (it would be different if we were defining methods
> inside the eval block, but we''re not)
i see.. you mean if we would do this??

def self.included(base)
  class_eval do
    ...
  end
end
> 
> Fred
-- 
Posted via http://www.ruby-forum.com/.

--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Talk" group.
To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en
-~----------~----~----~----~------~----~------~--~---

On 22 Jan 2008, at 10:28, Michal Gabrukiewicz wrote:
>
> Frederick Cheung wrote:
>
>> In this particular case it doesn''t make any difference.
instance_eval
>> means that self will be the base class (ie A) when the validates_*
>> calls are made. module_eval (which is the same as class eval) would  
>> do
>> the same thing (it would be different if we were defining methods
>> inside the eval block, but we''re not)
>
> i see.. you mean if we would do this??
>
I mean
module CommonStuff
  def self.included(base)
    base.instance_eval do
      validates_length_of :a, :in => 1..10
      validates_length_of :b, :in => 1..20
    end
  end

has the same effect as

module CommonStuff
  def self.included(base)
    base.class_eval do
      validates_length_of :a, :in => 1..10
      validates_length_of :b, :in => 1..20
    end
  end

but if your eval block had

def foo
end
then the method would be added in different places (A.foo instead of  
A.new.foo)

Fred
> def self.included(base)
>  class_eval do
>    ...
>  end
> end
>
>>
>> Fred
>
> -- 
> Posted via http://www.ruby-forum.com/.
>
> >

--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Talk" group.
To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en
-~----------~----~----~----~------~----~------~--~---

Frederick Cheung wrote:

oh i see now... thanks for your time! learned something again
> 
> but if your eval block had
> 
> def foo
> end
> then the method would be added in different places (A.foo instead of
> A.new.foo)
> 
> Fred
-- 
Posted via http://www.ruby-forum.com/.

--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Talk" group.
To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en
-~----------~----~----~----~------~----~------~--~---