feature/completions-customs 6b3c665d2a 1/3: completion-auto-help new values.

[Jimmy Aguilar Mena]

branch: feature/completions-customs
commit 6b3c665d2a8070791dff6520652c00c7b44d64bd
Author: Jimmy Aguilar Mena <spacibba@aol.com>
Commit: Jimmy Aguilar Mena <spacibba@aol.com>

    completion-auto-help new values.
    
    Added also entries to news and manual
---
 doc/emacs/mini.texi |  9 ++++++++-
 etc/NEWS            |  9 +++++++++
 lisp/minibuffer.el  | 29 ++++++++++++++++++-----------
 3 files changed, 35 insertions(+), 12 deletions(-)

diff --git a/doc/emacs/mini.texi b/doc/emacs/mini.texi
index 13d9269c68..5d351dd10b 100644
--- a/doc/emacs/mini.texi
+++ b/doc/emacs/mini.texi
@@ -628,7 +628,14 @@ commands never display the completion list buffer; you 
must type
 shows the completion list buffer on the second attempt to complete.
 In other words, if there is nothing to complete, the first @key{TAB}
 echoes @samp{Next char not unique}; the second @key{TAB} shows the
-completion list buffer.
+completion list buffer.  With the previous values and the default
+@code{t} the completions are hidden when some unique completion is
+executed.  If @code{completion-auto-help} is set to @code{always} the
+completion commands are always shown after a completion attempt or
+updated if they are already visible. If the value is @code{visible}
+then completions are not hidden, but updated if they are already
+visible while the current behavior stays the same as default if they
+are not.
 
 @vindex completion-cycle-threshold
   If @code{completion-cycle-threshold} is non-@code{nil}, completion
diff --git a/etc/NEWS b/etc/NEWS
index 80cf0a2f72..3d32513386 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -554,6 +554,15 @@ This option controls the sorting of the completion 
candidates in
 the "*Completions*" buffer.  Available styles are no sorting,
 alphabetical (the default), or a custom sort function.
 
+*** New values for the 'completion-auto-select' option.
+
+There are two new values to control the way *Completions* behave after
+a <tab> if completion is not unique.  'always updates or shows
+the *Completions* buffer after any attempt to complete.  'visual is
+like 'always, but only update the completions if they are already
+visible.  The default value t always hide the completion buffer after
+some completion is made.
+
 ** Isearch and Replace
 
 +++
diff --git a/lisp/minibuffer.el b/lisp/minibuffer.el
index 36b8d80841..c6a803cbc4 100644
--- a/lisp/minibuffer.el
+++ b/lisp/minibuffer.el
@@ -898,7 +898,11 @@ If the value is t the *Completions* buffer is displayed 
whenever completion
 is requested but cannot be done.
 If the value is `lazy', the *Completions* buffer is only displayed after
 the second failed attempt to complete."
-  :type '(choice (const nil) (const t) (const lazy)))
+  :type '(choice (const :tag "Disabled" nil)
+                 (const :tag "Enabled legacy" t)
+                 (const :tag "After a second attempt" lazy)
+                 (const :tag "Visible update" visible)
+                 (const :tag "Always update" always)))
 
 (defvar completion-styles-alist
   '((emacs21
@@ -1343,16 +1347,19 @@ when the buffer's text is already an exact match."
               (completion--cache-all-sorted-completions beg end comps)
               (minibuffer-force-complete beg end))
              (completed
-              ;; We could also decide to refresh the completions,
-              ;; if they're displayed (and assuming there are
-              ;; completions left).
-              (minibuffer-hide-completions)
-              (if exact
-                  ;; If completion did not put point at end of field,
-                  ;; it's a sign that completion is not finished.
-                  (completion--done completion
-                                    (if (< comp-pos (length completion))
-                                        'exact 'unknown))))
+              (cond
+               (exact
+                ;; If completion did not put point at end of field,
+                ;; it's a sign that completion is not finished.
+                (minibuffer-hide-completions)
+                (completion--done completion
+                                  (if (< comp-pos (length completion))
+                                      'exact 'unknown)))
+               ((pcase completion-auto-help
+                  ('visible (get-buffer-window "*Completions*" 0))
+                  ('always t))
+                (minibuffer-completion-help beg end))
+               (t (minibuffer-hide-completions))))
              ;; Show the completion table, if requested.
              ((not exact)
              (if (pcase completion-auto-help