Double extend of object

Ruby
1

does anyone know if this can be relied upon?

cfp:~ > cat a.rb
class C
def singleton_class &b
sc =
class << self;
self
end
b ? sc.instance_eval(&b) : sc
end
def extend m
ancestors = [singleton_class.ancestors,
self.class.ancestors].flatten.uniq
super(ancestors.index(m) ? m.dup : m)
end
end

module A
def foo() ‘A’ end
end

module B
def foo() ‘B’ end
end

c = C.new

c.extend A
p c.foo

c.extend B
p c.foo

c.extend A
p c.foo

cfp:~ > ruby a.rb
“A”
“B”
“A”

??

-a

2

ara.t.howard wrote:

does anyone know if this can be relied upon?

Is this the part you are really asking about?

module M; end

c = Object.new

c.extend M
c.extend M.dup

class << c; p ancestors; end

==> [#Module:0xb7cf26ac, M, Object, Kernel]

3

On May 21, 2007, at 4:15 PM, Joel VanderWerf wrote:

c.extend M.dup

class << c; p ancestors; end

==> [#Module:0xb7cf26ac, M, Object, Kernel]

yes :wink:

-a