* lisp/minibuffer.el (completion-metadata): Prepend the alist with `metadata'.

(completion-try-completion, completion-all-completions): Compute the
metadata argument if it's missing; make it optional.

Fixes: debbugs:8795

2 files changed, 16 insertions, 5 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 957c751750b..ceab0a14fcf 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,5 +1,9 @@
 2011-06-20  Stefan Monnier  <monnier@iro.umontreal.ca>
 
+        * minibuffer.el (completion-metadata): Prepend the alist with `metadata'.
+        (completion-try-completion, completion-all-completions): Compute the
+        metadata argument if it's missing; make it optional (bug#8795).
+
         * wid-edit.el: Use lexical scoping and move towards completion-at-point.
         (widget-complete): Use new :completion-function property.
         (widget-completions-at-point): New function.
diff --git a/lisp/minibuffer.el b/lisp/minibuffer.el
index 03e8225f0c5..a7ffc8d061a 100644
--- a/lisp/minibuffer.el
+++ b/lisp/minibuffer.el
@@ -135,7 +135,8 @@ The metadata of a completion table should be constant between two boundaries."
   (let ((metadata (if (functionp table)
                       (funcall table string pred 'metadata))))
     (if (eq (car-safe metadata) 'metadata)
-        (cdr metadata))))
+        metadata
+      '(metadata))))
 
 (defun completion--field-metadata (field-start)
   (completion-metadata (buffer-substring-no-properties field-start (point))
@@ -513,7 +514,7 @@ an association list that can specify properties such as:
         (delete-dups (append (cdr over) (copy-sequence completion-styles)))
        completion-styles)))
 
-(defun completion-try-completion (string table pred point metadata)
+(defun completion-try-completion (string table pred point &optional metadata)
   "Try to complete STRING using completion table TABLE.
 Only the elements of table that satisfy predicate PRED are considered.
 POINT is the position of point within STRING.
@@ -524,9 +525,12 @@ a new position for point."
   (completion--some (lambda (style)
                       (funcall (nth 1 (assq style completion-styles-alist))
                                string table pred point))
-                    (completion--styles metadata)))
+                    (completion--styles (or metadata
+                                            (completion-metadata
+                                             (substring string 0 point)
+                                             table pred)))))
 
-(defun completion-all-completions (string table pred point metadata)
+(defun completion-all-completions (string table pred point &optional metadata)
   "List the possible completions of STRING in completion table TABLE.
 Only the elements of table that satisfy predicate PRED are considered.
 POINT is the position of point within STRING.
@@ -537,7 +541,10 @@ in the last `cdr'."
   (completion--some (lambda (style)
                       (funcall (nth 2 (assq style completion-styles-alist))
                                string table pred point))
-                    (completion--styles metadata)))
+                    (completion--styles (or metadata
+                                            (completion-metadata
+                                             (substring string 0 point)
+                                             table pred)))))
 
 (defun minibuffer--bitset (modified completions exact)
   (logior (if modified    4 0)