Subject: Re: Optional Dependancies
To: Chris Gilbert <>
From: David Brownlee <>
List: tech-pkg
Date: 04/22/2001 00:28:05
	Have you taken a look at OpenBSD's flavours - they appear to be a
	determenistic way to solve the 'package variation' issue...

		David/absolute		-- No hype required --

On Sat, 21 Apr 2001, Chris Gilbert wrote:

> Hi,
> A while back I mentioned something about the idea of having optional
> dependancies.  Having stumbled onto something I'd like, but perhaps not
> everyone, I decided it's about time I came up with a more concrete suggestion.
> what are optional dependancies?
> Optional dependancies will allow the ability to have extra features turned on
> if you have that package installed.  Eg kdepim2 would enable kpilot if you've
> got misc/pilot-link installed, something that not everyone would want but
> some might.  It might also assist in cases of circular dependancies.
> How do we handle binary packages?
> My suggestion would be that if an optional package was found on the build
> system then it becomes a dependancy for that binary package.  This will
> complicate doing bulk builds, but it depends on how many optional
> dependancies there are.  However to handle this it would perhaps be worth
> having a global flag saying ignore optional dependancies.
> How would it be implemented?
> I'd expect that it's use would  do something like:
> OPTIONAL_DEPENDS +=	pilot-link>=0.9.3:../../misc/pilot-link:message about
> what this extra package will add.
> If it finds something in the OPTIONAL_DEPENDS section installed it adds it to
> DEPENDS.  If it doesn't find the package it can optionally display the
> message as to what functionality would be added.
> If an optional package needs to set options to enable the functionality some
> way of detecting this might be needed eg:
> .if ${OPT_pilot-link}
> 	CONFIGURE_ENV+=  -enable-palm-link
> .endif
> I believe that implementing the OPTIONAL_DEPENDS should be possible, but
> doing an implementation of the .if parts maybe somewhat trickier (it's been a
> long time since I last did makefile work)
> I'm hoping that others have suggestions and ideas on why or why this would
> [not] work.  If it looks like people are interested I'll actually do some
> work on trying to implement it.
> Cheers,
> Chris