From: Alexandru Popescu <the.mindstorm.mailinglist@...>
Date: 2005-08-21T11:02:25+09:00
Subject: include and extend Module - Ruby Way

Hi!

I am reading the excellent The Ruby Way. I most probably not understand correctly the following pieces:

[quote page=38]
With include, the module's methods become available as instance methods; with extend, they become 
available as class methods
[/quote]

I have written the following code example:

[code]
module ExampleModule
	def moduleMethod
	    puts 'module method'
	end
end

class IncludeModule
     include ExampleModule
end

class ExtendModule
     extend ExampleModule
end

im = IncludeModule.new
# IncludeModule.moduleMethod # this is correct
im.moduleMethod # module method becomes instance method

em = ExtendModule.new
ExtendModule.moduleMethod # module method becomes class method
em.moduleMethod # this is failing! WHY?
[/code]

As pointed above the em#moduleMethod is failing. Being a class method I expect it to be available 
also on every instance. What I wrongly understood?

Later I can read the following:

[quote page=275]
The extend method will mix a module into an object. The instance methods from the module become 
instance methods for the object.
[/quote]

Isn't this in contradiction with the first quote?

Please enlighten me.

:alex |.::the_mindstorm::.|