Re: Subprojects in project.el (Was: Eglot, project.el, and python virtual environments)

[Eli Zaretskii]

> Date: Fri, 25 Nov 2022 19:24:26 +0200
> Cc: joaotavora@gmail.com, monnier@iro.umontreal.ca, danny@dfreeman.email,
>  eric@ericabrahamsen.net, emacs-devel@gnu.org
> From: Dmitry Gutov <dgutov@yandex.ru>
> 
> On 25/11/22 09:30, Eli Zaretskii wrote:
> > I'm probably missing something: how does a Lisp program construct an
> > instance of a project with a known backend?  For example, if the project is
> > of the 'transient' kind, how would such a Lisp program go about constructing
> > an instance without exposing/knowing about the internals of the project
> > object?  I see no generic make-project API that such a Lisp program could
> > call.  What did I miss?
> 
> The Lisp program that constructs instances of 'transient' is 
> 'project-current'.

I meant to ask about building customized project objects, not the standard
ones that are already created by project-current.  This started with a
function João wrote to that effect, and he wrote it, AFAIU, because the
standard kinds of project objects didn't satisfy his needs.

> The program that creates instances of 'vc' type is called 
> 'project-try-vc'. But we could similarly add a generic method belonging 
> to the same unit of code (called 'project-subprojects') which would 
> "belong" to the VC project backend and create a list of instances of its 
> type.

Again, you are talking about project kinds already supported by project.el
as its built-ins.  I'm asking how to produce a project of a custom type.