From: Michael Morin <uzimonkey@...>
Date: 2008-08-20T08:50:28+09:00
Subject: Re: passing a variable from a block back to the method

James Dinkel wrote:
> Michael Morin wrote:
>> You can also use catch and throw.  I think this method is a little 
>> cleaner.
>>
> 
> ah, I think I like the catch and throw method.  That's pretty close to 
> what I was visualizing in my head.
> 
> Just one thing though:
> 
>> class File
>>
>>    def self.change(filename)
>>      catch(:nochanges) do
>>        # read the file, execute a block, then write the file
>>        File.open(filename, 'r+') do|file|
>>          lines = file.readlines
>>
>>          # return if not changing anything
>>          return if yield(lines) == false
>>
>>          file.pos = 0
>>          file.print lines
>>          file.truncate(file.pos)
>>        end
>>      end
>>    end
>> end
>>
> 
> You left in the "return if yield(lines) == false", was that a typo?  I'm 
> guessing it was.

Oh yeah, that is a typo left over from the other example.  That line 
should read just "yield lines".

-- 
Michael Morin
Guide to Ruby
http://ruby.about.com/
Become an About.com Guide:  beaguide.about.com
About.com is part of the New York Times Company