Re: Subprojects in project.el

[Dmitry Gutov]

On 30/11/2022 00:52, João Távora wrote:
> Dmitry Gutov <dgutov@yandex.ru> writes:
>
> > What do you mean, without breaking compatibility? Adding a new
> > required argument means it will break any Lisp code that calls this
> > function.
>
> The example I gave you was for a function explicitly marked "interactive
> only", so it's not a problem.  In fact all these functions should be
> "interactive only".  But in other cases, make that argument optional.

The commands that are marked 'interactive-only' are those that we have 
decided are useless in Lisp programs. Others aren't marked such.

> > +(defun project-parent (project)
> > +  (project-current nil (file-name-as-directory
> > +                        (file-name-directory
> > +                         (directory-file-name (project-root project))))))
> > +
> > +(defun project-current-or-parent (lookup-parent)
> > +  (let ((project (project-current t)))
> > +    (when lookup-parent
> > +      (setq project (project-parent project)))
> > +    (unless project
> > +      (user-error "No parent project"))
> > +    project))
> > +
> >   (defcustom project-compilation-buffer-name-function nil
> >     "Function to compute the name of a project compilation buffer.
> >   If non-nil, it overrides `compilation-buffer-name-function' for
> > @@ -1155,7 +1168,8 @@ project-compile
> >     "Run `compile' in the project root."
> >     (declare (interactive-only compile))
> >     (interactive)
> > -  (let ((default-directory (project-root (project-current t)))
> > +  (let ((default-directory (project-root (project-current-or-parent
> > +                                          (eq current-prefix-arg '-))))
> >           (compilation-buffer-name-function
> >            (or project-compilation-buffer-name-function
> >                compilation-buffer-name-function)))
>
> Sounds more complicated that it needs to be, and no reason why
> project-current-or-parent shouldn't be just project-current, with
> another optional argument at most.

If it's a new optional argument vs new function, I can see the benefits 
of either. OT1H, project-current is shorter.

OT2H, some code (or even a person) might like to check (fboundp 
'project-current-or-parent).

Anyway, I'm not crazy about the name of the argument (lookup-parent), so 
suggestions are welcome on that.