bug#18643: 25.0.50; elisp--expect-function-p

[Stefan Monnier]

> It is the false negatives that kill its usefulness in the case of elisp.
> For example, (ert-deftest |) and (defun |) no longer have the
> completions I need.

Dmitry, what is it exactly that changed?
I mean, Elisp completion has been context-sensitive "for ever", so the
change is not that it now is, but that it now reacts to the
context differently.

Oh, I think I see: the change is the introduction of
elisp--form-quoted-p such that if elisp--form-quoted-p returns nil
(and we're not expecting a function), we only complete against var names
instead of the previous behavior of expanding against "anything".

I think this is not right: we should have a elisp--expect-exp-p
which returns non-nil in a context where we know the symbol at point
should be a valid expression (i.e. a variable).  Not sure how to write
it, tho, but in its absence I think we're better off completing against
"anything" than restricting ourselves to variables.

BTW, to improve on these behaviors, one approach is to take the
macro-expansion code used in elisp--local-variables and use it
"everywhere".  I.e. expand elisp--local-variables so it doesn't just
return the list of local vars, but also returns whether we're inside
a quote, or we're expecting a function, or we're expecting an expression.


        Stefan