From: Robert Klemme <shortcutter@...>
Date: 2010-01-22T18:32:15+09:00
Subject: Re: Ruby equivalent of C# "using keword" and IDispose

2010/1/22 Allen Lee <allenlooplee@gmail.com>:
> I finally came up with this toy:

This looks interesting.  Although I have to say that the functionality
should be rather built into the classes at hand (like e.g. File has)
IMHO.

> def using(res, options = { release_with: :close })

Since you have a single option only you can as well do

def using(res, close = :close)

>  yield res
> ensure
>  if res.respond_to?(options[:release_with])
>    res.send(options[:release_with])
>  end

I'd rather do

  res.send(options[:release_with]) rescue nil

Because the idea of respond_to? and what the class really understands
may differ.

irb(main):001:0> class X
irb(main):002:1> def method_missing(s,*a,&b)
irb(main):003:2>   "I can #{s}!"
irb(main):004:2> end
irb(main):005:1> end
=> nil
irb(main):006:0> o = X.new
=> #<X:0x101596fc>
irb(main):007:0> o.respond_to? :dance
=> false
irb(main):008:0> o.dance
=> "I can dance!"
irb(main):009:0> o.dance!
=> "I can dance!!"
irb(main):010:0>

> end
>
> Note that you need to go back to :release_with => "close" if you are
> targeting version before 1.9.

This is not necessary if you just use a single additional parameter (see above).

Kind regards

robert


-- 
remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/