From: Luke Kanies <luke@...>
Date: 2006-08-20T14:11:23+09:00
Subject: Re: Dir.bitbucket?

On Aug 19, 2006, at 11:34 PM, Daniel Berger wrote:

> Hi all,
>
> Occasionally I have to do something like this:
>
> bitbucket = RUBY_PLATFORM.match('mswin') ? 'NUL' : '/dev/null'
>
> How about a Dir.bitbucket method? Or Dir.null, or whatever you want  
> to call it.

it's not quite the same thing, since it's not a part of the Ruby  
core, but I've got a library, Facter[1], specifically meant to help  
handle this kind of platform variety.  This kind of simple code would  
look like this:

Facter.add :bitbucket do
	setcode do
		case Facter.operatingsystem
		when /mswin/i: 'NUL'
		when /amiga/i: 'NIL'
		when /openvms/i: 'NL:'
		else
			'/dev/null'
		end
	end
end

The reason the code is set separately is that, for more complicated  
facts, you could have a separate resolution mechanism for every  
platform:

Facter.add :bitbucket do
	confine :operatingsystem => :mswin
	setcode { "NUL" } # strings get executed as shell code, so you have  
to use a block
end

Facter.add :bitbucket do
	confine :operatingsystem => :amiga
	setcode { "NIL" }
end
...

Any fact can be be confined based on other facts, so you could  
confine a fact to work only on a given release of a specific platform  
(e.g., Mac OS X seems to change the config file that stores the IP  
configuration on every release).

The interface could probably be slimmed down some, but the basic idea  
is there:  Make it simple to get a fact on different platforms.  It's  
especially useful for things like domain names, which can often be  
resolved multiple ways (/etc/resolv.conf, /bin/domainname, dns, /etc/ 
hosts, etc.)


1 - http://reductivelabs.com/projects/facter

-- 
Luke Kanies
http://madstop.com | http://reductivelabs.com | 615-594-8199