Add e method "inline" to an object?

ruby-talk
1

Hi, I know that I can extend a Class instance (an object) with a
method(s) by doing:

  object.extend Module

but can I do it in a "inline" way without the need of a module?
I just want something as follows:

  time = Time.now
  object.add_method 'def say_time(); return time; end'

  > object.say_time
  --> time

Note that I **don't** want to include the "add_method" in object class
or in Object class. This is, I don't want to "dirty" object class.

Also note that I can't use "object.extend Module" since the method
"say_time" must return a variable "time" value that I pass as an
argument.

Is there some way? Thanks a lot.

···

--
Iñaki Baz Castillo
<ibc@aliax.net>

2

I'll explain it by example:

a = "a"
#=> "a"
class << a
   def fooify
    return "foo #{self}"
   end
end

a.fooify
#=> "foo a"
b = "b"
#=> "b"
b.fooify
#NoMethodError: undefined method `fooify' for "b":String
# from (irb):9
# from :0

···

On Aug 20, 2008, at 6:31 PM, Iñaki Baz Castillo wrote:

Hi, I know that I can extend a Class instance (an object) with a
method(s) by doing:

object.extend Module

but can I do it in a "inline" way without the need of a module?
I just want something as follows:

time = Time.now
object.add_method 'def say_time(); return time; end'

> object.say_time
--> time

Note that I **don't** want to include the "add_method" in object class
or in Object class. This is, I don't want to "dirty" object class.

Also note that I can't use "object.extend Module" since the method
"say_time" must return a variable "time" value that I pass as an
argument.

Is there some way? Thanks a lot.

--
Iñaki Baz Castillo
<ibc@aliax.net>

3

You can do this with singleton methods:

   irb(main):001:0> object = Object.new
   => #<Object:0x304af8>

   irb(main):002:0> def object.say_time; Time.now; end
   => nil

   irb(main):003:0> object.say_time
   => Wed Aug 20 10:13:29 -0700 2008

···

On Aug 20, 2008, at 9:31 AM, Iñaki Baz Castillo wrote:

Hi, I know that I can extend a Class instance (an object) with a
method(s) by doing:

object.extend Module

but can I do it in a "inline" way without the need of a module?
I just want something as follows:

time = Time.now
object.add_method 'def say_time(); return time; end'

> object.say_time
--> time

--
Michael Granger <ged@FaerieMUD.org>
Rubymage, Architect, Believer
The FaerieMUD Consortium <http://www.FaerieMUD.org/&gt;

4

Thanks to both :slight_smile:

···

El Miércoles, 20 de Agosto de 2008, Michael Granger escribió:

You can do this with singleton methods:

   irb(main):001:0> object = Object.new
   => #<Object:0x304af8>

   irb(main):002:0> def object.say_time; Time.now; end
   => nil

   irb(main):003:0> object.say_time
   => Wed Aug 20 10:13:29 -0700 2008

--
Iñaki Baz Castillo