From: LAMBEAU Bernard <blambeau@...>
Date: 2009-01-10T00:22:48+09:00
Subject: Re: How Ruby

Ruby allows you to install methods on objects (called singleton
methods because installed on individual objects instead of being
shared by all instances of a class):

o = Object.new
def o.sayhello
  puts "hello"
end

o.sayhello    # prints hello to the console

blambeau

On Fri, Jan 9, 2009 at 3:25 PM, Stuart Ellis <stuart@stuartellis.eu> wrote:
>
> On 9 Jan 2009, at 13:30, David A. Black wrote:
>
>> Hi --
>>
>> On Fri, 9 Jan 2009, Tom Cloyd wrote:
>>
>>> Thanks Mike. I appreciated your post. I'm an awful Ruby programmer, and
>>> write tightly organized, well documented procedural Ruby. I'm only now,
>>> after probably 1.5 years of on and off work in the language, getting around
>>> to writing classes. I really couldn't see why I'd want to, until very
>>> recently. Then, thanks to some folks on this list, I "got it". I can't wait
>>> to dive in to using classes, now.
>>
>> Dave Thomas issued a challenge in a recent keynote address, where he
>> suggested that when each of us writes our next Ruby program, we try to
>> do it without writing any classes. It's an artificial exercise, of
>> course, but it keeps the focus on the objects as opposed to the class
>> hierarchy, which is all to the good in most cases.
>>
>> When I teach the Ruby language, I actually illustrate singleton
>> methods before I talk about classes, because I consider the dynamism
>> of objects (their independence from their classes) to be a more
>> important foundational principle of Ruby than the fact that every
>> object is an instance of a class. Mind you, like everyone else I write
>> "class Thing" more often than "def thing.something" in my own code (I
>> think :-) But it's still important, in my view, to get the hang of the
>> fact that Ruby classes are not the center of gravity.
>>
>> So it sounds like you've done it in the right order :-) Keep modules
>> in mind, too. They're very cool, especially when you #extend objects
>> with them....
>
> *Raises hand*
>
> At the risk of looking very silly, could I ask you to say a bit more about
> this? As a newbie, I have automatically read "object" to mean "an instance
> of a defined class", and assumed that object orientation in Ruby leads to
> mostly thinking in terms of classes.
>
> Thank you,
>
> --
> Stuart Ellis
> http://www.stuartellis.eu
>
>
>