From: Eric Hodel <drbrain@...7.net>
Date: 2006-11-16T06:49:30+09:00
Subject: Re: #returning and #tap

On Nov 8, 2006, at 6:40 AM, Trans wrote:

> Had use for this today: #returning is a convenience method you'll find
> in both Facets and ActiveSupport. Jamis' blogged it the other day:
>
> http://weblog.jamisbuck.org/2006/10/27/mining-activesupport-object- 
> returning
>
> Any one else think this is worthy of standard Ruby?

 From the blog post:

>> The latter is no shorter than the former, but it reads more  
>> elegantly. It feels more �Rubyish�. And there are times that it  
>> can save you a few lines of code, if that�s important. (Just scan  
>> the Rails source code for more examples.)

So... it usually doesn't save any lines, it adds typing, it hides the  
object you're returning in the middle of a statement and it is  
significantly more expensive to execute[1].  (Oh, but maybe, in some  
cases, it might save you one or two lines of code.)

No thanks.

I don't think that makes it more rubyish.  Every time I've  
encountered #returning in Rails I've found it decreased the  
readability of the code and uselessly increased the complexity.   
(Wait, now what does this return? oh, yeah, way up there.)

1:

Rehearsal ---------------------------------------------
empty       0.290000   0.000000   0.290000 (  0.391447)
returning   5.120000   0.050000   5.170000 (  5.467861)
regular     2.660000   0.020000   2.680000 (  2.900946)
------------------------------------ total: 8.140000sec

                 user     system      total        real
empty       0.300000   0.000000   0.300000 (  0.316623)
returning   5.160000   0.050000   5.210000 (  5.815804)
regular     2.650000   0.020000   2.670000 (  2.824744)

require 'benchmark'

def returning(value)
   yield(value)
   value
end

N = 1_000_000

Benchmark.bmbm do |bm|
   bm.report 'empty' do
     N.times do end
   end

   bm.report 'returning' do
     N.times do returning(Object.new) do |o| o.nil? end end
   end

   bm.report 'regular' do
     N.times do o = Object.new; o.nil?; o end
   end

end

-- 
Eric Hodel - drbrain@segment7.net - http://blog.segment7.net
This implementation is HODEL-HASH-9600 compliant

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