#append_features deprecated?

Ruby
1

Somone else mentioned this. Is it true?

Thanks,
T.

2

Trans wrote:

Somone else mentioned this. Is it true?

This says Module#included " should be used in preference to
Module.append_features if your code wants to perform some action when a
module is included in another."

http://www.ruby-doc.org/core/classes/Module.html#M000704

Cheers,
Dave

3

Dave B. wrote:

Dave
module M
def self.included(klass)
puts “Included in #{klass}”
end
end

class A
include M # -> Included in A
end

class B
M.append_features(self) # Nothing
end

As you can see, Module#append_features doesn’t call the .included method
on the module, include does.

Cheers,
Daniel

4

Daniel S. wrote:

Cheers,
end
Daniel
Oooops, #append_features is private, so it should be

M.send :append_features, self

Cheers,
Daniel

5

ts wrote:

def self.included(klass)

module M
end
Guy Decoux
Um, yeah. append_features' does the actual work (appending the methods of a module to a class/module),include’ just calls append_features' and thenincluded’.

class Module
def include(*mods)
mods.each do |mod|
mod.append_features(self)
mod.included(self)
end
end
end

Cheers,
Daniel

6

“D” == Daniel S. [email protected] writes:

D> Um, yeah. append_features' does the actual work (appending the methods D> of a module to a class/module), include’ just calls
append_features' D> and then included’.

yes, and this is why you must call super in #append_features (if you
redefine it) otherwise ruby don’t include the module.

Guy Decoux

7

ts wrote:

“D” == Daniel S. [email protected] writes:

D> Um, yeah. append_features' does the actual work (appending the methods D> of a module to a class/module), include’ just calls append_features' D> and then included’.

yes, and this is why you must call super in #append_features (if you
redefine it) otherwise ruby don’t include the module.

Guy Decoux

Yup.

8

“D” == Daniel S. [email protected] writes:

D> As you can see, Module#append_features doesn’t call the .included
method
D> on the module, include does.

Well, it’s best to see it like this :

moulon% cat b.rb
#!/usr/bin/ruby
module M
def self.included(klass)
puts “Included in #{klass}”
end
def a
puts “a”
end
end

class A
include M
end

A.new.a
moulon%

moulon% ./b.rb
Included in A
a
moulon%

moulon% cat b.rb
#!/usr/bin/ruby
module M
def self.append_features(klass)
puts “Included in #{klass}”
end
def a
puts “a”
end
end

class A
include M
end

A.new.a
moulon%

moulon% ./b.rb
Included in A
./b.rb:15: undefined method `a’ for #<A:0xb7d64b38> (NoMethodError)
moulon%

Guy Decoux

9

Daniel S. wrote:

   end
 end

end

It does? Looking at the C code it seems a lot more complicated then
that.

T.