From: Joel VanderWerf <vjoel@...>
Date: 2005-08-09T04:50:25+09:00
Subject: Re: polymorphism and/or named parameters: the ruby way?

Eric Mahurin wrote:
...
> Functionally, I guess something like this would be most
> flexible (no performance advantage like "ensure"):
> 
> class Object
>   def post
>     yield(self)
>     self
>   end
> end
> 
> Then you could do these types of things:
> 
> a[i.post{i+=1}]
> 
> foo = Foo.new.post do |f|
>    f.bar = "hello"
>    f.baz = 5
>    f.zap = "world"
> end
> 
> With this, no need for the "yield(self) if block_given?" in
> initialize.
> 
> This very useful little method is a nice thing to have in your
> bag-o-tricks.

Nice. you could even call it #then:

class Object
  def then
    yield(self)
    self
  end
end

#Then you could do these types of things:
a = (0..10).to_a
i = 3
p a[i.then{i+=1}]
p i

Foo = Struct.new :bar, :baz, :zap

foo = Foo.new.then do |f|
   f.bar = "hello"
   f.baz = 5
   f.zap = "world"
end

p foo

__END__

output:

3
4
#<struct Foo bar="hello", baz=5, zap="world">

-- 
      vjoel : Joel VanderWerf : path berkeley edu : 510 665 3407