From: James Edward Gray II <james@...>
Date: 2007-10-03T08:00:33+09:00
Subject: Re: Config files

On Oct 1, 2007, at 6:21 PM, Lee Jarvis wrote:

> I am writing an application that will read and grab values from a
> configuration file. I am wondering what peoples opinions are on  
> what to
> use. YAML? XML? Does anyone have any preference? Are any better  
> then the
> others or is it just down to user preference?

YAML tends to work out well, when it's very simple data fields being  
collected.  That said, YAML's syntax rules are quite complex and  
asking a user to edit any non-trivial data in the format is a bad  
idea, in my opinion.

If you need markup at all, use XML.  It's a markup language, after  
all.  YAML is not.

Also, while more verbose, XML has a much easier syntax that far more  
people are familiar with.  I'm not saying that means you have to use  
it, but it's something to stay aware of.

Finally, I've used this trick a couple of times now and I just love it:

#!/usr/bin/env ruby -wKU

require "ostruct"

module Config
   module_function

   def load_config_file(path)
     eval <<-END_CONFIG
     config = OpenStruct.new
     #{File.read(path)}
     config
     END_CONFIG
   end
end

__END__

That let's me do my configurations in pure Ruby, which may or may not  
be appropriate for your needs.

I guess the most important thing is to consider your audience.

James Edward Gray II