Super bug or (most likely) I am doing something wrong?


(Philip Mateescu) #1

Hi,

I can’t seem to get it right with a super (newbie stuff :)).
I expect the following program :

···

class Boo
def say_what
puts "boo what ?"
end
end

a = Boo.new
a.say_what

class Foo < Boo
def say_what
super.say_what
puts "FOO this!"
end
end

b = Foo.new
b.say_what

to output
boo what?
boo what?
FOO this!

Instead I get :

boo what ?


on ruby 1.7.2 (2002-03-29) [i686-cygwin]

and

boo what ?
boo what ?
class_object_vars.rb:12:in say_what': undefined methodsay_what’ for nil
(NoMethodError)
from class_object_vars.rb:18

on ruby 1.7.2 (2002-03-20) [i386-mswin32]

class_object_vars.rb:12: being the super.say_what line…

Could someone please clear me out why is this happening ?

Thanks,
philip


(Tobi Reif) #2

Philip Mateescu wrote:

  • super.say_what
  • super

Tobi

···


http://www.pinkjuice.com/


(Marko Schulz) #3

I can’t seem to get it right with a super (newbie stuff :)).
:
class Foo < Boo
def say_what
super.say_what
puts "FOO this!"
end
end
:
Could someone please clear me out why is this happening ?

To quote matz from ruby-talk:38327

···

On Tue, Jun 04, 2002 at 03:37:07AM +0900, Philip Mateescu wrote:

it should be super(). Forget your Smalltalk (or Objective-C)
experience about “super”.


marko schulz


(Philip Mateescu) #4

Thank you Tobias and thank you Marko.

However, what if I would want to call another method of its ancestor ?
Something along the lines of :
class Boo
def say_what
puts "boo what?"
def
def say_who
puts "class Boo"
end
end

class Foo < Boo
def say_what
# none of the following three work
super.say_who # xor
super().say_who # xor
super.send :say_who #

I do have an extra question (TIA) : why does it (Foo.new.say_what) still
prints “boo what?” in all three cases ?
Does it executes super (thus Boo#say_what) and then gets lots in which is
the current object ?

Thanks,
philip

···

----- Original Message -----
From: “Tobias Reif” tobiasreif@pinkjuice.com
To: “ruby-talk ML” ruby-talk@ruby-lang.org
Sent: Monday, 03 June, 2002 9:48 PM
Subject: Re: super bug or (most likely) I am doing something wrong ?

Philip Mateescu wrote:

  • super.say_what
  • super

Tobi


http://www.pinkjuice.com/


#5

“Philip Mateescu” philip@dynasty.com wrote in message news:010e01c20b36$51276130$0a01a8c0@DynRom.local

Thank you Tobias and thank you Marko.

However, what if I would want to call another method of its ancestor ?
Something along the lines of :
class Boo
def say_what
puts "boo what?"
def
def say_who
puts "class Boo"
end
end

class Foo < Boo
def say_what
# none of the following three work
super.say_who # xor
super().say_who # xor
super.send :say_who #

I do have an extra question (TIA) : why does it (Foo.new.say_what) still
prints “boo what?” in all three cases ?

super # <== looks for say_what in superclass

so, your example is calling the Boo.say_what, then trying to send a
say_who message to the returned value. also, does do what you want?

class Foo < Boo
alias say_what say_who
end

hope this was helpful, I’m a little bleary eyed right now.

night,

Patrick