Re: Managing environments (Python venv, guix environment, etc.)

[Dmitry Gutov]

On 07/18/2016 10:13 PM, address@hidden wrote:
> Stefan Monnier <address@hidden> writes:
> > That was my assumption: your "environments" correspond to
> > specific subdirectories in the file-system.
>
> Nope, not necessarily. Python virtualenvs do have an associated
> directory that contains the installed libraries for that
> environment. But guix environment only updates environment variables to
> point to the locations of already existing libraries, and so guix
> environments don't exist in the filesystem at all. They're only a
> runtime thing. (Libraries are installed on demand at fixed paths when
> constructing an environment, and garbage-collected later)

How will the guix environment to use be determined, then?

If it's strictly "prompt the user", that might be incompatible with the 
way project.el determines the current project.

> Oh, no, I do want to get this into Emacs. Because the use of these kind
> of environments is pretty common at this point, and it would be nice if
> Emacs natively understood them in a generic way. Then, yes, ELPA
> packages could build on that functionality to support specific
> kinds of environments. Same with the new project and xref functionality.

We can't move xref to ELPA because Emacs's default key bindings use it. 
And project.el, because it's used by xref.

> Yes, I think this is important functionality that other packages
> distributed with Emacs should be able to build on. Using virtualenvs is
> very common for Python, for example, and Emacs should support that.

I don't see why virtualenvs support can't be distributed via GNU ELPA, 
too. Anyway, as soon as python.el decides to depend on it, we could move 
environment.el to the core.

> Also, since this is a headline feature of GNU Guix, it would be nice to
> support it in GNU Emacs.

I'm sure people working on that distribution can pre-install a few ELPA 
packages.