Forum: Ruby Singleton method

C:\>ruby -v
ruby 2.0.0p0 (2013-02-24) [i386-mingw32]

C:\>irb --simple-prompt
DL is deprecated, please use Fiddle
>> N = 1
=> 1
>> obj = Object.new
=> #<Object:0x2166c00>
>> class << obj
>> N = 2
>> end
=> 2
>> def obj.a_method
>> puts N
>> end
=> nil
>> class << obj
>> def another_method
>> puts N
>> end
>> end
=> nil
>> obj.a_method
1
=> nil
>> obj.another_method
2
=> nil
>>

Both `a_method` and `another_method` are the singleton methods of the
object `obj`. Then why gave different output for `N` ?

Because def obj.foo uses the top-level value of N = 1, whereas the
class << obj; ...; end version uses the value of N previously defined
in that scope, and is thus 2. Different scopes.

both `another_method` and `a_method` are the singleton methods of
`obj`. Does they reside in the same singleton class? if not where
does `a_method` lives?

Thanks

Scopes and look-ups for Ruby constants.

Adam Prescott wrote in post #1101486:
> Scopes and look-ups for Ruby constants.

Couldn't understand you. :(

Here is a decent article on the matter:
http://jfire.io/blog/2011/01/21/making-sense-of-co...

Basically, it seems arbitrary how constant lookup works :(