Inheriting from FalseClass fails

ruby-talk
1

Apologies if that is covered somewhere. I searched the FAQ and
could not find it.

Consider this code snippet:

class Klass < FalseClass
def initialize(*args)
puts "It works"
end
end

‘ruby -v example.rb’ gives:
ruby 1.6.8 (2002-11-07) [i686-linux]
example.rb:2: warning: overriding global function initialize' example.rb:7: undefined methodnew’ for Klass:Class (NameError)

Klass.methods shows that Klass is indeed missing the method new.
The same applies for FalseClass.

Is it possible to inherit from FalseClass (or NilClass, for that
matter)?
Benedikt

2

It doesn’t work because “new” is explicitly undefined in object.c.
FalseClass ist just the class of the sole object “false” and can’t be
instantiated. However, if you want to add methods to FalseClass you can
just reopen it:

class FalseClass

def foo
	"foo"
end

end
==>nil
false.foo
==>“foo”

···

On 2002-11-20 03:29:53 +0900, Benedikt Rosenau wrote:

Consider this code snippet:

class Klass < FalseClass
def initialize(*args)
puts “It works”
end
end

‘ruby -v example.rb’ gives:
ruby 1.6.8 (2002-11-07) [i686-linux]
example.rb:2: warning: overriding global function initialize' example.rb:7: undefined method new’ for Klass:Class (NameError)

Klass.methods shows that Klass is indeed missing the method new.
The same applies for FalseClass.

Is it possible to inherit from FalseClass (or NilClass, for that
matter)?

–
Java and C++ make you think that the new ideas are like the old ones. Java
is the most distressing thing to hit computing since MS-DOS.
– Alan Kay