Hi,
I' ve got problem with instance_eval.
I tried the following with irb:
obj = "3"
=> "3"
obj.instance_eval "def a ; puts 'x'; end"
=> nil
obj.a
x
=> nil
obj = 3
=> 3
obj.instance_eval "def a ; puts 'x'; end"
TypeError: (eval):1:in `irb_binding': no class/module to add method
from (irb):31
Why does the instance_eval not work for the Fixnum?
Best regards,
Thomas
Alle Wednesday 20 February 2008, bitmox ha scritto:
Hi,
I' ve got problem with instance_eval.
I tried the following with irb:
>> obj = "3"=> "3"
>> obj.instance_eval "def a ; puts 'x'; end"
=> nil
>> obj.a
x
=> nil>> obj = 3
=> 3
>> obj.instance_eval "def a ; puts 'x'; end"
TypeError: (eval):1:in `irb_binding': no class/module to add method
from (irb):31Why does the instance_eval not work for the Fixnum?
Best regards,
Thomas
instance_eval works for Fixnums. For example:
(-1).instance_eval("abs")
=> 1
The problem is that you can't define singleton methods for Fixnums (this is
also true for Floats and Bignums):
x = 1
def x.a
end
=> TypeError: can't define singleton method "a" for Fixnum
Stefano
Alle Wednesday 20 February 2008, bitmox ha scritto:
> Hi,
> I' ve got problem with instance_eval.
> I tried the following with irb:
> >> obj = "3"> => "3"
> >> obj.instance_eval "def a ; puts 'x'; end"
> => nil
> >> obj.a
> x
> => nil> >> obj = 3
> => 3
> >> obj.instance_eval "def a ; puts 'x'; end"
> TypeError: (eval):1:in `irb_binding': no class/module to add method
> from (irb):31> Why does the instance_eval not work for the Fixnum?
> Best regards,
> Thomas
Hi Stefano,
thank you for your hint.
I checked the documentation for Fixnum meanwhile. There is described,
that is impossible to a singleton method.
Thomas
On 20 Feb., 13:43, Stefano Crocco <stefano.cro...@alice.it> wrote:
instance_eval works for Fixnums. For example:
(-1).instance_eval("abs")
=> 1The problem is that you can't define singleton methods for Fixnums (this is
also true for Floats and Bignums):x = 1
def x.a
end
=> TypeError: can't define singleton method "a" for FixnumStefano