From: gabriele renzi <surrender_it@...>
Date: 2005-05-23T16:30:25+09:00
Subject: Re: Gem Dependancies

Jeremy Hinegardner ha scritto:
> On Mon, May 23, 2005 at 10:24:27AM +0900, James Edward Gray II wrote:
> 
>>On May 22, 2005, at 7:12 PM, Jim Weirich wrote:
>>
>>
>>>On Sunday 22 May 2005 01:27 pm, James Edward Gray II wrote:
>>>
>>>
>>>>With HighLine, we've recently moved over to using termios... on Unix
>>>>only.  I set it up as a gem dependancy and this is causing problems
>>>>with the Window's install (and we don't even need it on that
>>>>platform).  That leads me to the following questions:
>>>>
>>>>1.  Is it possible to change dependancies based on the platform?
>>>>
>>>
>>>Not within a single gem.  You could provide separate gems with  
>>>different
>>>dependencies.
>>
>>Do a few projects do this?  Can you point me toward an example project?
>>
>>Is this on the RubyGems feature request list?  If not, can I put it  
>>there?  :)
> 
> 
> I'll add to it too...
> 
> I'm looking at a need for 'optional' dependencies.   That is, given a
> list of dependencies, at least one of them must be installed for the gem
> to work.
<snip>

I think this are called "virtual" more than optional.
I definitely agree this is needed, but I also see the need for 
"optional" gems (which AFAICT are not there, though I may be wrong).
Say, actioncontroller has an utility method that rely on RedCloth.

Putting the whole RedCloth as a dependency would be an overkill, but 
telling the user they *could* cooperate would be needed imho.