bug#47665: elisp-completion-at-point doesn't work when no characters typed

[Dmitry Gutov <dgutov@yandex.ru>]

X-Debbugs-CC: Stefan Monnier <monnier@IRO.UMontreal.CA>

Example:

(|)

press C-M-i -> nothing

(a|)

press C-M-i -> lots of completions

That's not very conducive to API exploration via completion.

Further, it triggers a problem when used with company: if I initiate 
completion when prefix is empty, it switches to the dabbrev-code 
backend. Then, even after I type some chars, the same backend continues 
to be used. Not company-capf, which I would want.

This patch seems to fix it:

diff --git a/lisp/progmodes/elisp-mode.el b/lisp/progmodes/elisp-mode.el
index 8ade718640..203712f45d 100644
--- a/lisp/progmodes/elisp-mode.el
+++ b/lisp/progmodes/elisp-mode.el
@@ -496,7 +496,7 @@ elisp-completion-at-point
  	   (end
  	    (unless (or (eq beg (point-max))
  			(member (char-syntax (char-after beg))
-                                '(?\s ?\" ?\( ?\))))
+                                '(?\" ?\()))
  	      (condition-case nil
  		  (save-excursion
  		    (goto-char beg)


But I'm not sure why those elements were there in the first place.