From: Ron Jeffries <ronjeffries@...>
Date: 2002-01-13T14:07:25+09:00
Subject: Re: FileHandle (was: Re: Dir.entries have no home)

On Sun, 13 Jan 2002 02:56:32 GMT, Massimiliano Mirra
<list@chromatic-harp.com> wrote:

>  def location=(new)
>    @info[:location][:new] = new
>    @info[:path][:new]     = File.join(@info[:location][:new], @info[:name][:new])
>  end
>
>  def name=(new)
>    @info[:name][:new] = new
>    @info[:path][:new] = File.join(@info[:location][:new], @info[:name][:new])
>  end
>  
>  def path=(new)
>    @info[:path][:new]     = new
>    @info[:name][:new]     = File.basename(@info[:path][:new])
>    @info[:location][:new] = File.dirname(@info[:path][:new])
>  end

A couple more things, then I really am going to bed. Seems like that
last method could be written as

>  def path=(new)
>    @info[:path][:new]     = new
>    @info[:name][:new]     = File.basename(new)
>    @info[:location][:new] = File.dirname(new))
>  end

unless I'm missing something. Am I?

 Also, it seems that these methods are trying to maintain a
consistency relationship between name, path, and location. 

Why not instead just let path be virtual and maintain the other two,
something like this:

>  def location=(new)
>    @info[:location][:new] = new
>  end
>
>  def name=(new)
>    @info[:name][:new] = new
>  end
>  
>  def path=(new)
>    @info[:name][:new]     = File.basename(new)
>    @info[:location][:new] = File.dirname(new)
>  end

with also

> def path
>    File.join(@info[:location][:new], @info[:name][:new])
> end

Wouldn't something like that be simpler and less prone to error?

Then, finally, instead of the hash, I might prefer to set up an object
of class, say, FileInfo with instance variables and accessors
location, path, name and so on, and to have two instances of FileInfo
in FileHandle, @newInfo and @oldInfo, so we could write

def name=(new)
  @newInfo.name=new
end

and the like. Maybe there's some complex manipulation of the new and
old that I don't understand yet that would get in the way of doing
this ...

Or maybe I just don't get it. Hmm?

Regards,

Ronald E Jeffries
http://www.XProgramming.com
http://www.objectmentor.com
I'm giving the best advice I have. You get to decide whether it's true for you.