Retrieving an object by it's id

ruby-talk
1

Hello,

how can I write a method f which fullfills the following
specification?

The function f has one Fixnum argument oi.
f(oi) == [true, obj], if there's an object obj with obj.object_id == oi;
f(oi) == [false, nil], otherwise.

Regards
  Thomas

2

def f(oi)
  g = [false, nil]
  ObjectSpace.each_object { |a|
    g = [true, a] if a.object_id == oi
  }
  g
end

···

On Mon, Jan 29, 2007 at 02:15:11AM +0900, Thomas Hafner wrote:

Hello,

how can I write a method f which fullfills the following
specification?

The function f has one Fixnum argument oi.
f(oi) == [true, obj], if there's an object obj with obj.object_id == oi;
f(oi) == [false, nil], otherwise.

--
Aaron Patterson
http://tenderlovemaking.com/

3

Aaron Patterson <aaron_patterson@speakeasy.net> wrote/schrieb <20070128190516.GA5600@eviladmins.lan>:

def f(oi)
  g = [false, nil]
  ObjectSpace.each_object { |a|
    g = [true, a] if a.object_id == oi
  }
  g
end

Thanks, but:
4.object_id
=> 9
f(9)
=> [false, nil]
I'd expect [true,4], instead.

Regards
  Thomas

4

You don't want to use #each_object for this - this is way to inefficient. You want #_id2ref:

irb(main):006:0> ObjectSpace._id2ref 4.object_id
=> 4
irb(main):007:0> ObjectSpace._id2ref "foo".object_id
=> "foo"

Kind regards

  robert

···

On 28.01.2007 19:18, Thomas Hafner wrote:

Aaron Patterson <aaron_patterson@speakeasy.net> wrote/schrieb <20070128190516.GA5600@eviladmins.lan>:

def f(oi)
  g = [false, nil]
  ObjectSpace.each_object { |a|
    g = [true, a] if a.object_id == oi
  }
  g
end

Thanks, but:
4.object_id
=> 9
f(9)
=> [false, nil]
I'd expect [true,4], instead.