Define and use `completion-table-merge'

* lisp/minibuffer.el (completion-table-merge): New function.

* lisp/emacs-lisp/lisp.el (lisp-completion-at-point): Use
`completion-table-merge' instead of `completion-table-in-turn'.

Fixes: debbugs:16604

3 files changed, 35 insertions, 1 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 5ce9ab4913c..571f9547279 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,11 @@
+2014-02-06  Dmitry Gutov  <dgutov@yandex.ru>
+
+        * emacs-lisp/lisp.el (lisp-completion-at-point): Use
+        `completion-table-merge' instead of `completion-table-in-turn'
+        (bug#16604).
+
+        * minibuffer.el (completion-table-merge): New function.
+
 2014-02-05  Michael Albinus  <michael.albinus@gmx.de>
 
         * net/tramp-sh.el (tramp-end-of-heredoc): New defconst.
diff --git a/lisp/emacs-lisp/lisp.el b/lisp/emacs-lisp/lisp.el
index 3ff4f64d24c..716df8a4cca 100644
--- a/lisp/emacs-lisp/lisp.el
+++ b/lisp/emacs-lisp/lisp.el
@@ -830,7 +830,7 @@ considered."
                 ;; use it to provide a more specific completion table in some
                 ;; cases.  E.g. filter out keywords that are not understood by
                 ;; the macro/function being called.
-                (list nil (completion-table-in-turn
+                (list nil (completion-table-merge
                            lisp--local-variables-completion-table
                            obarray)       ;Could be anything.
                       :annotation-function
diff --git a/lisp/minibuffer.el b/lisp/minibuffer.el
index c87fcc1c3ea..105075524bf 100644
--- a/lisp/minibuffer.el
+++ b/lisp/minibuffer.el
@@ -388,11 +388,37 @@ Note: TABLE needs to be a proper completion table which obeys predicates."
   "Create a completion table that tries each table in TABLES in turn."
   ;; FIXME: the boundaries may come from TABLE1 even when the completion list
   ;; is returned by TABLE2 (because TABLE1 returned an empty list).
+  ;; Same potential problem if any of the tables use quoting.
   (lambda (string pred action)
     (completion--some (lambda (table)
                         (complete-with-action action table string pred))
                       tables)))
 
+(defun completion-table-merge (&rest tables)
+  "Create a completion table that collects completions from all TABLES."
+  ;; FIXME: same caveats as in `completion-table-in-turn'.
+  (lambda (string pred action)
+    (cond
+     ((null action)
+      (let ((retvals (mapcar (lambda (table)
+                               (try-completion string table pred))
+                             tables)))
+        (if (member string retvals)
+            string
+          (try-completion string
+                          (mapcar (lambda (value)
+                                    (if (eq value t) string value))
+                                  (delq nil retvals))
+                          pred))))
+     ((eq action t)
+      (apply #'append (mapcar (lambda (table)
+                                (all-completions string table pred))
+                              tables)))
+     (t
+      (completion--some (lambda (table)
+                          (complete-with-action action table string pred))
+                        tables)))))
+
 (defun completion-table-with-quoting (table unquote requote)
   ;; A difficult part of completion-with-quoting is to map positions in the
   ;; quoted string to equivalent positions in the unquoted string and