Where and how is defined "attr_accessor"?

[Iñaki Baz Castillo]

Hi, I've done some custom "field_accessor" (similar to "attr_accessor" but=
=20
with some neccessary difference). It works perfectly if I=20
defined "field_accessor" in the same class:

class Header
def self.field_accessor(name)
module_eval %{ def #{name}() .... end }
end
end

class From < Header
field_accessor :user, :domain
end


But I'd like to have field_accessor definition out of "Header" class, maybe=
in=20
a module but don't get it working. If I do:

module FieldAccessor
module_eval %{ def #{name}() .... end }
end

class From
include FieldAccessor
field_accessor :user, :domain
end


Then I get:
NoMethodError: undefined method `field_accessor' for From:Class


Later I've tryed with the following and it seems to work:

module FieldAccessor
module_eval %{ def #{name}() .... end }
# It also works with "class_eval".
end

class From
extend FieldAccessor
field_accessor :user, :domain
end



So, while I was writting this mail I found the solution, but would like to=
=20
know if it's the correct way. Thanks a lot.

=2D-=20
I=C3=B1aki Baz Castillo

 

[Iñaki Baz Castillo]

El Mi=C3=A9rcoles, 30 de Abril de 2008, David A. Black escribi=C3=B3:

The last two definitions of FieldAccessor look wrong; you haven't
defined the field_accessor method. But assuming that you correct that,
then yes, extending your class is the best way.

Yes, sorry, what I did is:

module FieldAccessor
def self.field_accessor(name)
module_eval %{ def #{name}() .... end }
# It also works with "class_eval".
end
end

class From
extend FieldAccessor
field_accessor :user, :domain
end

To answer the question in your subject line: attr_accessor is an
instance method of Module. That's why all modules and classes can call
it. You could add field_accessor to Module, but extend is cleaner.

Nice to know, so I was in the good way

Thanks a lot for your help.



=2D-=20
I=C3=B1aki Baz Castillo

 

[Ken Bloom]

El Miércoles, 30 de Abril de 2008, David A. Black escribió:

Another reasonable place is in class Module. See Ruby Quiz #67:
Metakoans, which involved creating an attr_accessor like method.
http://www.rubyquiz.com/quiz67.html

--Ken