Re: [PATCH] Add yaggo.

[Pjotr Prins]

On Wed, Jun 24, 2015 at 08:32:51AM -0400, Thompson, David wrote:
> I don't know about $GEM_SPEC_CACHE, but $GEM_HOME cannot be a native
> search path that is part of our ruby packages, because native search
> paths are relative to store items, which are immutable.  My feeling is
> that if the user wants to use the 'gem' utility instead of using Guix
> packages, they're going to have to set an environment variable or two
> by themselves.

It is just a convenience. I believe GNU Guix should allow extra
package systems - like those of emacs. So point GEM_HOME to something
that is not immutable.

> > which would install directly from rubygems.org (including contained
> > dependencies when missing in the existing environment).
> 
> Are you saying that it would bundle the dependencies if there were no
> Guix packages for them?

Exactly.

> > This would greatly facilitate adding Ruby gems to guix.
> 
> I must reiterate my concern about this approach to the wider
> guix-devel audience.  From what I can see, the gem archives hosted on
> rubygems.org are build artifacts and should probably be treated like
> pre-built binaries.  They are not the complete, corresponding source
> code.  Can anyone else weigh in here?  I understand the convenience of
> using rubygems.org, but I really need some evidence that the archives
> hosted there are complete, corresponding source code.

Please see it as a migration path. There are tens of thousands of
useful gems out there with complex dependencies. There is no way we
are going to replace and test those overnight. Same for Python and
Perl modules (and all those other languages with their own module
system). I do favour pure Guix packages, also for gems, so we should
aim for replacing the most important ones over time. 

Making it hard(er) to install gems from GNU Guix for normal users will
only slow down adoption. Allow using rubygems for those gems that are
not (yet) supported by us. When enough Ruby people move to using Guix
for their development we may get rid of rubygems altogether. I would
love that. I already got rid of rvm :)

Nix experimented by converting all gems to Nix packages, that is
another possibility. But I think they proved it is hard and now
defunct (correct me if I am wrong). 

Pj.