As I said in my previous post, I need to override some AR accessor
methods. I thought that alias_method would work, it didn''t, I believe
because AR methods are invoked via method_missing. I thought
alias_attribute would work, but apparently that just makes a copy of the
accessor methods, so the original and the alias both point to the same
thing.
What I got to work was this - I need to get the object''s name, unless
it''s nil and the object is a child in acts_as_tree.
def name
if read_attribute(:name)
read_attribute(:name)
elsif read_attribute(:parent_id)
self.parent.name
end
end
def real_name
read_attribute(:name)
end
I don''t know if I need the real_name accessor, but either way
it''s ugly
to write out a method like the name method for each of the 10 attributes
I need to do this with. Any suggestions would be much appreciated.
Jason
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I''ve have to be overriding a _lot_ of accessors to want to get any more
clever than:
def name
my_or_parental(:name)
end
def nationality
my_or_parental(:nationality)
end
# ...
def my_or_parental(attrib)
if read_attribute(attrib)
read_attribute(attrib)
elsif self.parent_id
self.parent.send(attrib)
end
end
Ciao,
Sheldon.
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Right on - I was thinking along those lines on the way home from work. I''ve never really done any programming of this type(is this meta-programming?), but I think I''m going to try for something like this: defaults_to_parent :attr_1, :attr_2, :attr_3 I''ll post back if I get anything in case anyone else needs something like this. Jason On 1/22/07, Sheldon Hearn <sheldonh-Uqlk7TKVmMlWaveUIWBRJg@public.gmane.org> wrote:> > > > I''ve have to be overriding a _lot_ of accessors to want to get any more > clever than: > > def name > my_or_parental(:name) > end > > def nationality > my_or_parental(:nationality) > end > > # ... > > def my_or_parental(attrib) > if read_attribute(attrib) > read_attribute(attrib) > elsif self.parent_id > self.parent.send(attrib) > end > end > > Ciao, > Sheldon. > > > > >--~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
Hello Jason,> Right on - I was thinking along those lines on the way home from > work. I've never really done any programming of this type(is this > meta-programming?), but I think I'm going to try for something > like this: > > defaults_to_parent :attr_1, :attr_2, :attr_3 > > I'll post back if I get anything in case anyone else needs something > like this.You can write something like this : class MyModel < AR::B def self.defaults_to_parent(*getters) getters.each do |method| class_eval(<<-EOM, __FILE__, __LINE__) def #{method} if read_attribute(:#{method}) read_attribute(:#{method}) elsif read_attribute(:parent_id) self.parent.#{method} end end EOM end end defaults_to_parent :attr_1, :attr_2, :attr_3 end (not tested) HTH, -- Jean-François. -- À la renverse. --~--~---------~--~----~------------~-------~--~----~ 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@googlegroups.com To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe@googlegroups.com For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
Thank you , Jean-François. As far as I can tell, it works perfectly. If my object has a nil attribute, it defaults to the parent, and if the paren''t attribute is nil too, it returns nil. I''m not sure if I understand, though, what __FILE__ and __LINE__ do. OK, those params are just for error reporting. I was thinking I would have to use eval, I didn''t know about class_eval and it probably would have taken me awhile to figure it out. Your help is much appreciated. Jason Jean-François wrote:> Hello Jason, > > >> Right on - I was thinking along those lines on the way home from >> work. I''ve never really done any programming of this type(is this >> meta-programming?), but I think I''m going to try for something >> like this: >> >> defaults_to_parent :attr_1, :attr_2, :attr_3 >> >> I''ll post back if I get anything in case anyone else needs something >> like this. >> > > You can write something like this : > > class MyModel < AR::B > def self.defaults_to_parent(*getters) > getters.each do |method| > class_eval(<<-EOM, __FILE__, __LINE__) > def #{method} > if read_attribute(:#{method}) > read_attribute(:#{method}) > elsif read_attribute(:parent_id) > self.parent.#{method} > end > end > EOM > end > end > > defaults_to_parent :attr_1, :attr_2, :attr_3 > end > > (not tested) > > HTH, > > -- Jean-François. > >--~--~---------~--~----~------------~-------~--~----~ 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@googlegroups.com For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---