From: Simon Mullis <simon@...>
Date: 2007-09-28T19:54:12+09:00
Subject: Fwd: how to do "do" blocks

I posted this earlier, but it didn't get through... (see my other post
"Ac Cautionary Tale").

hehe

SM

---------- Forwarded message ----------
From: Simon Mullis <simon@mullis.co.uk>
Date: Sep 28, 2007 10:32 AM
Subject: Re: how to do "do" blocks
To: ruby-talk@ruby-lang.org


Hey

The "do..end" and "{..}" are almost equivalent (although "{..}" has
higher precedence).

So,

collection_of_objects = []
 10.times do
   collection_of_objects << MyObject.create
end

Is the equivalent to:

collection_of_objects = []
 10.times {
   collection_of_objects << MyObject.create
}


But (from the Ruby Cookbook), you may need to look at precedence.

So,

1.upto 3 do |x|
  puts x
end

is ok.

But,

1.upto 3 { |x|
 puts x
end

is not, as the code block binds to the 3, not the function call.

So, it would have to be:

1.upto(3) { |x|
 puts x
end

Hope this helps!

SM

On 9/28/07, Daniel Talsky <danieltalsky@gmail.com> wrote:
> How come this works:
>
> collection_of_objects = []
> 10.times do
>   collection_of_objects << MyObject.create
> end
>
> But this doesn't:
>
> collection_of_objects = []
> 10.times do { collection_of_objects << MyObject.create }
>
> I didn't understand there was ANY difference between the two syntaxes
> really.  Can someone explain to me the finer points?
> --
> Posted via http://www.ruby-forum.com/.
>
>


--
Simon Mullis
_________________
simon@mullis.co.uk


-- 
Simon Mullis
_________________
simon@mullis.co.uk