Re: To Yield or Not to Yield: An Inferable Question

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From	Brian Candler <b.candler@pobox.com>
Newsgroups	comp.lang.ruby
Subject	Re: To Yield or Not to Yield: An Inferable Question
Date	Mon, 18 Apr 2011 10:53:08 -0500
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Michael Edgar wrote in post #993395:
>> 1. In my experience, very little real-world Ruby code uses
>> 'block_given?'. If it needs to yield, it just yields. I'd consider this
>> to be a case of duck-typing.
>
> This seems to suggest Rubyists rarely write methods that take blocks
> optionally. Of this, I am highly skeptical.

Ah, by "optionally" I think you mean "does one thing when a block is 
given, but something else when a block is not given". Now I think some 
more, there is a fairly common case:

class MyFile
  def self.open(*args)
    file = open_it(*args)
    if block_given?
      begin
        yield file
      ensure
        file.close
      end
    else
      return file
    end
  end
end

Code analysis can tell you that it's OK to call the method either with 
or without a block (at least assuming no pathological use cases, like 
redefining 'block_given?')

Regards,

Brian.

-- 
Posted via http://www.ruby-forum.com/.

Thread

[ANN] To Yield or Not to Yield: An Inferable Question Michael Edgar <adgar@carboni.ca> - 2011-04-14 12:47 -0500
  Re: To Yield or Not to Yield: An Inferable Question Brian Candler <b.candler@pobox.com> - 2011-04-17 15:22 -0500
    Re: To Yield or Not to Yield: An Inferable Question Michael Edgar <adgar@carboni.ca> - 2011-04-17 16:40 -0500
      Re: To Yield or Not to Yield: An Inferable Question Ryan Davis <ryand-ruby@zenspider.com> - 2011-04-18 03:41 -0500
      Re: To Yield or Not to Yield: An Inferable Question Brian Candler <b.candler@pobox.com> - 2011-04-18 10:53 -0500
      Re: To Yield or Not to Yield: An Inferable Question Brian Candler <b.candler@pobox.com> - 2011-04-20 03:59 -0500
        Re: To Yield or Not to Yield: An Inferable Question Michael Edgar <adgar@carboni.ca> - 2011-04-20 16:46 -0500
          Re: To Yield or Not to Yield: An Inferable Question Brian Candler <b.candler@pobox.com> - 2011-04-21 04:47 -0500
            Re: To Yield or Not to Yield: An Inferable Question Robert Klemme <shortcutter@googlemail.com> - 2011-04-21 06:18 -0500
              Re: To Yield or Not to Yield: An Inferable Question Brian Candler <b.candler@pobox.com> - 2011-04-21 12:55 -0500
  Re: [ANN] To Yield or Not to Yield: An Inferable Question Robert Klemme <shortcutter@googlemail.com> - 2011-04-18 04:34 -0500
    Re: [ANN] To Yield or Not to Yield: An Inferable Question Michael Edgar <adgar@carboni.ca> - 2011-04-18 04:46 -0500
      Re: [ANN] To Yield or Not to Yield: An Inferable Question Robert Klemme <shortcutter@googlemail.com> - 2011-04-18 06:16 -0500
        Re: [ANN] To Yield or Not to Yield: An Inferable Question Michael Edgar <adgar@carboni.ca> - 2011-04-18 07:26 -0500

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