From: James Edward Gray II <james@...>
Date: 2005-12-08T23:47:02+09:00
Subject: Re: do/end vs braces

On Dec 8, 2005, at 8:13 AM, Joe Van Dyk wrote:

> On 12/8/05, Steve Litt <slitt@earthlink.net> wrote:
>> Hi all,
>>
>> It looks to me like when you use an iterator (each for instance),  
>> you can make
>> the block either from a do/end pair, or from curly braces. All  
>> things being
>> equal, I'd greatly prefer to use do/end. Are there any differences  
>> in runtime
>> speed, capabilities, or Rubyness?
>
> Typically,
>
> 5.times { |i| puts i }
>
> 5.times do |i|
>   puts i
> end
>
> Generally people save do .. end for multiline stuff.  Don't think
> there's a difference in speed.

Another convention some use is that { ... } are for the times when  
you care about the return value and do ... end is for when you're  
interested in the side effects.  For example:

sum = [1, 2, 3].inject { |sum, n| sum + n }  # return value

File.open("total.txt", "w") do |file|  # side effects
   file.puts sum
end

James Edward Gray II