Singleton Methods

Ruby
1

Could anyone explain what exactly we meant by a Singleton Method ?
See if i am thinking it right…

class A
end
a = A.new
a.instance_eval <<-EOS
def wishing_hello
puts “HELLO !!”
end
EOS

so, here wishing_hello will be a singleton method ?

2

Hi –

On Sat, 11 Nov 2006, sur max wrote:

EOS

so, here wishing_hello will be a singleton method ?

Yes. A singleton method is basically a method that belongs to one
object only. Since methods actually “belong to” classes and modules,
rather than objects in general, Ruby implements singleton methods by
means of singleton classes. Each object has its own, dedicated class
– its singleton class – where its singleton methods are stored.

You can gain direct access to an object’s singleton class like this:

class << a # from your example
def wishing_goodbye
puts “GOODBYE!!”
end
end

wishing_goodbye is now defined as an instance method in the singleton
class of a.

David

3

Thanks David !!

4

:fr sur max [mailto:[email protected]]

Could anyone explain what exactly we meant by a Singleton Method ?

See if i am thinking it right…

fr ola bini’s blog
Ola Bini: Programming Language Synchronicity: The Ruby singleton class.

just in case you want to think ruby :slight_smile:

kind regards -botp