In Smalltalk its normal to add behavior to third party and kernel classes if said behavior feels “natural” to said class. That’s one of the reasons why you won’t find classes like StringUtils in Smalltalk. Instead if a behavior is something that a String should do well that’s where it goes.

I’m reminded of this because recently I was working on a task where I need to use “zipping” in Ruby. I naturally went to RubyGems which is my default stop to look for Ruby “goodies” where I found the gem rubyzip. Scanning thru the api I could not find something where I could just stipulate the path to a zip file and consequently ask it to extract itself to a destination path. i.e.

file = ZipFile.open 'myzip.zip'

file.extract_to '/home/charles/extracts'

Unfortunately , the exact api wasn’t quite there. I Googled and found folks complaining about the same thing. I also found somebody that actually provided the implementation that achieved the objectives which was fine except for where it was implemented.
The code I found was this:

def extract_archive (file, destination)

Zip::ZipFile.open(file) { |zip_file|
 zip_file.each { |f|
 f_path=File.join(destination, f.name)
 FileUtils.mkdir_p(File.dirname(f_path))
 zip_file.extract(f, f_path)
 }
 }
end

That rubs the Smalltalker in me the wrong way and actually I’m sure it bothers the experienced Ruby developer as well. Ruby like Smalltalk has been built around a culture of thinking of objects and messages but many that come from C and Java backgrounds are just not used to thinking that way.
Ruby has a very nice and simple way of providing for class extensions. All you have to do is simply re-state the class definition and add the methods you want to extend the class with. I therefore created an extension ruby file I called ZipFileExtensions.rb which goes like this:

class Zip::ZipFile

#Instance Side Methods

def extract_to destination

self.each { |f|
 f_path=File.join(destination, f.name)
 FileUtils.mkdir_p(File.dirname(f_path))
 extract(f, f_path)
 }

end

end

This allows me to simply ask a zip_file extract_to destination.
Just like God intended.