From: "s.ross" <cwdinfo@...>
Date: 2008-02-20T08:34:40+09:00
Subject: Re: Is there any object-oriented File class in ruby ?

On Feb 19, 2008, at 2:45 PM, tom_33 wrote:

> For example, the ruby method File.basename is documented as only
> supporting forward slashes, regardless of the local file system.
> File.basename("/home/gumby/work/ruby.rb")          #=> "ruby.rb"
> Essentially, this seems to be not much more than a string parsing
> function with no OO abstraction that represents a file object.
> Compare this with doing the same thing with java:
> File f = new File("/home/gumby/work/ruby.rb"); // or new File("C:\ 
> \home
> \\gumby\\work\\ruby.rb");
> f.getName() #=> "ruby.rb"

File is an OO abstraction and the fact that you don't see explicit  
support for alternative path separators does not bear on object  
orientedness. Consider this:

class WinFile < File
   def self.basename(filename, suffix ='')
     File.basename(filename.gsub(/\\/, '/'), suffix)
   end
end

That allows you to use WinFile everywhere you might have used File,  
complete with File's attributes, collections, iterators, and so on. It  
sounds like you are more *used* to Java's implementation of this class.

The reason for the "pure" adjective is that everything is derived from  
a base class, Object. Fixnum, String, File, everything. So anything  
that works on Object works on all of these. Try this:

irb
 >> 1.public_methods
# long list of methods follows
 >> 1.public_methods - Object.public_methods
# shorter list of methods belonging to Fixnum. How do we know?
 >> 1.class
=> Fixnum

This kind of introspection and single-root object-orientation is much  
more difficult in more static languages and allows for much of the  
"magic" of Ruby.