Re: Generalizing find-definition

[Stefan Monnier]

> For Python, there is nothing suitable for "identifier at point" that I

Yet, you say that you offer a tab-completable selection of identifiers.
So obviously, there is a suitable "identifier at point".

Do you mean by the above not that the concept is meaningless but that
it's difficult to write a function that reliably returns the appropriate
identifier at point?

If so, I can definitely agree that for some modes it can be difficult,
and it should not be necessary to write such a function if the backend
can use a buffer-position instead (and delegate the hard work to some
external tool).

But having such an identifier-at-point-function can be useful for all
kinds of things (typically default for minibuffer inputs of various
commands), so it makes a lot of sense to standardize it.

> For Python, I do provide a tab-completable list of identifiers
> (currently only for pydoc, but the code should be reusable for this),
> but it is not a simple list of identifiers, but a tree. The tab
> completion starts with top-level modules (like "json"), but when you
> add a ".", it will continue to complete attributes of the module or
> class etc.. Providing the full list of possible completions right
> away would take a very long time.

Of course.  But such completion is nothing new.  File names are
completed this way.  Bzr revision names are completed this way as well.
No need for a special completion command, you can do that just fine with
just a completion-table (and then partial-completion style will let you
complete "js.fo" to anything that matches "js*.fo*").

Note that such completion tables are clearly not lists of strings, but
they're functions (actually, they're objects represented as functions,
for lack of an object system).

> This is getting extremely complex and I do not see how this would
> benefit the user much.

As long as the "set of use-kinds" and the "set of identifier categories"
is determined by the backend itself, I don't think it increases
complexity of the backends or the backend API very much.

And there are clearly example of existing systems which do provide such
refinements (e.g. find-variable vs find-function on Elisp, and the C-c
C-w s versus C-c C-w b versus C-c C-w r in SLIME), so it makes sense to
include it in the design of the backend API.

> There are definitions of an identifier, and uses of an identifier.

Yes, clearly this is the main distinction and we should focus on this
functionality w.r.t designing the UI.


        Stefan