[Q] class and case

ruby-talk
1

Hi,

a = 3

#A
case a
   when Fixnum
     p "Fixnum"
end

#B
case a.class
   when Fixnum
     p "Fixnum"
end

why ist #A working while #B isn't?

Thanks!

Eric.

2

% ri "Module.==="
------------------------------------------------------------- Module#===
     mod === obj => true or false

···

On Thu, 29 Jul 2004 22:01:53 +0900, E.-R. Bruecklmeier <unet01@radio-eriwan.de> wrote:

Hi,

a = 3

#A
case a
   when Fixnum
     p "Fixnum"
end

#B
case a.class
   when Fixnum
     p "Fixnum"
end

why ist #A working while #B isn't?

------------------------------------------------------------------------
     Case Equality---Returns +true+ if _anObject_ is an instance of
     _mod_ or one of _mod_'s descendents. Of limited use for modules,
     but can be used in +case+ statements to classify objects by class.

Thus:

  case a.class
    when Fixnum
      p "Fixnum" # => Never Reached
    when Class
      p "Class!" # => or Object, or Module, or several others, see
a.class.ancestors
  end

-austin
--
Austin Ziegler * halostatue@gmail.com
               * Alternate: austin@halostatue.ca

3

Because #A and #B are not the same!

Gavin

···

On Thursday, July 29, 2004, 11:01:53 PM, E.-R. wrote:

Hi,

a = 3

#A
case a
   when Fixnum
     p "Fixnum"
end

#B
case a.class
   when Fixnum
     p "Fixnum"
end

why ist #A working while #B isn't?

4

Austin Ziegler schrieb:

% ri "Module.==="
------------------------------------------------------------- Module#===
     mod === obj => true or false
------------------------------------------------------------------------
     Case Equality---Returns +true+ if _anObject_ is an instance of
     _mod_ or one of _mod_'s descendents. Of limited use for modules,
     but can be used in +case+ statements to classify objects by class.

Thanks a lot!

Eric.