Re: completion-at-point + semantic : erroneous error

[Stefan Monnier]

> PS: It would also be good to replace uses of
> define-overloadable-function with cl-defmethod, although the mapping
> from one to the other is not immediate.

The patch below is an attempt to do that for
semantic-analyze-possible-completions.  I'd be interested to hear your
opinion on this (especially the with-mode-local part).


        Stefan


diff --git a/lisp/cedet/semantic/analyze/complete.el 
b/lisp/cedet/semantic/analyze/complete.el
index b471c0d1a1..193c975c47 100644
--- a/lisp/cedet/semantic/analyze/complete.el
+++ b/lisp/cedet/semantic/analyze/complete.el
@@ -63,7 +63,7 @@ semantic-analyze-tags-of-class-list
 ;;; MAIN completion calculator
 ;;
 ;;;###autoload
-(define-overloadable-function semantic-analyze-possible-completions (context 
&rest flags)
+(cl-defgeneric semantic-analyze-possible-completions (context &optional flags)
   "Return a list of semantic tags which are possible completions.
 CONTEXT is either a position (such as point), or a precalculated
 context.  Passing in a context is useful if the caller also needs
@@ -83,7 +83,9 @@ semantic-analyze-possible-completions
   * Argument to a function with type constraints.
 When called interactively, displays the list of possible completions
 in a buffer."
-  (interactive "d")
+  (semantic-analyze-possible-completions-default context flags))
+
+(cl-defmethod semantic-analyze-possible-completions :around (context &rest 
flags)
   ;; In theory, we don't need the below since the context will
   ;; do it for us.
   ;;(semantic-refresh-tags-safe)
@@ -93,8 +95,9 @@ semantic-analyze-possible-completions
                          context
                        (semantic-analyze-current-context context)))
             (ans (if (not context)
-                     (error "Nothing to complete")
-                   (:override))))
+                     (when (called-interactively-p 'any)
+                       (error "Nothing to complete"))
+                   (cl-call-next-method))))
        ;; If interactive, display them.
        (when (called-interactively-p 'any)
          (with-output-to-temp-buffer "*Possible Completions*"
diff --git a/lisp/cedet/semantic/bovine/make.el 
b/lisp/cedet/semantic/bovine/make.el
index 3676c6972f..dbfa060b5d 100644
--- a/lisp/cedet/semantic/bovine/make.el
+++ b/lisp/cedet/semantic/bovine/make.el
@@ -32,9 +32,6 @@
 (require 'semantic/analyze)
 (require 'semantic/dep)
 
-(declare-function semantic-analyze-possible-completions-default
-                 "semantic/analyze/complete")
-
 ;;; Code:
 (define-lex-analyzer semantic-lex-make-backslash-no-newline
   "Detect and create a beginning of line token (BOL)."
@@ -174,13 +171,13 @@ semantic-format-tag-uml-prototype
 This is the same as a regular prototype."
   (semantic-format-tag-prototype tag parent color))
 
-(define-mode-local-override semantic-analyze-possible-completions
-  makefile-mode (context)
+(cl-defmethod semantic-analyze-possible-completions
+  (context &context (major-mode makefile-mode) &rest _)
   "Return a list of possible completions in a Makefile.
 Uses default implementation, and also gets a list of filenames."
   (require 'semantic/analyze/complete)
   (with-current-buffer (oref context buffer)
-    (let* ((normal (semantic-analyze-possible-completions-default context))
+    (let* ((normal (cl-call-next-method))
           (classes (oref context prefixclass))
           (filetags nil))
       (when (memq 'filename classes)
diff --git a/lisp/cedet/semantic/grammar.el b/lisp/cedet/semantic/grammar.el
index 813580ba6c..6767cb10fc 100644
--- a/lisp/cedet/semantic/grammar.el
+++ b/lisp/cedet/semantic/grammar.el
@@ -1914,13 +1914,15 @@ semantic-analyze-current-context
 
       context-return)))
 
-(define-mode-local-override semantic-analyze-possible-completions
-  semantic-grammar-mode (context)
+(cl-defmethod semantic-analyze-possible-completions
+  (context &context (major-mode semantic-grammar-mode) &rest _)
   "Return a list of possible completions based on CONTEXT."
   (require 'semantic/analyze/complete)
   (if (semantic-grammar-in-lisp-p)
+      ;; FIXME: Does the `let' make the `with-mode-local' redundant here?
       (with-mode-local emacs-lisp-mode
-       (semantic-analyze-possible-completions context))
+       (let ((major-mode 'emacs-lisp-mode))
+         (semantic-analyze-possible-completions context)))
     (with-current-buffer (oref context buffer)
       (let* ((prefix (car (oref context prefix)))
             (completetext (cond ((semantic-tag-p prefix)
diff --git a/lisp/cedet/semantic/texi.el b/lisp/cedet/semantic/texi.el
index 3a0050b920..510c4ea043 100644
--- a/lisp/cedet/semantic/texi.el
+++ b/lisp/cedet/semantic/texi.el
@@ -412,8 +412,8 @@ semantic-texi-command-completion-list
          )
   "List of commands that we might bother completing.")
 
-(define-mode-local-override semantic-analyze-possible-completions
-  texinfo-mode (context)
+(cl-defmethod semantic-analyze-possible-completions
+  (context &context (major-mode texinfo-mode) &rest _)
   "List smart completions at point.
 Since texinfo is not a programming language the default version is not
 useful.  Instead, look at the current symbol.  If it is a command