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

[Eric Ludlam <ericludlam@gmail.com>]

On 10/11/19 1:34 PM, Stefan Monnier wrote:
>> 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).
>
Hi Stefan,


As a followup, I started using the shorter version of your patch, and 
found there are additional errors thrown from 
semantic-analyze-possible-completions-default (what will be a method in 
your patch).  I had to eliminate those errors to fully clean up the 
original problem that started this thread.

I used catch/throw to solve the problem (see below: patch is against the 
original semantic/analyze/complete.el, not your patched version with 
methods.)

As an added wrinkle on the `should it be interactive' front, there is a 
keybinding in semantic.el for semantic-analyze-possible-completions that 
would need to be dealt with.


Eric



diff --git a/lisp/cedet/semantic/analyze/complete.el 
b/lisp/cedet/semantic/analyze/complete.el
index b471c0d1a1..b8820b927f 100644
--- a/lisp/cedet/semantic/analyze/complete.el
+++ b/lisp/cedet/semantic/analyze/complete.el
@@ -93,7 +93,8 @@ semantic-analyze-possible-completions
                context
              (semantic-analyze-current-context context)))
           (ans (if (not context)
-              (error "Nothing to complete")
+              (when (called-interactively-p 'any)
+                        (error "Nothing to complete"))
              (:override))))
      ;; If interactive, display them.
      (when (called-interactively-p 'any)
@@ -132,155 +133,159 @@ semantic-analyze-possible-completions-default
       (do-unique (not (memq 'no-unique flags)))
       )

-    (when (not do-longprefix)
-      ;; If we are not doing the long prefix, shorten all the key
-      ;; elements.
-      (setq prefix (list (car (reverse prefix)))
-        prefixtypes nil))
-
-    ;; Calculate what our prefix string is so that we can
-    ;; find all our matching text.
-    (setq completetext (car (reverse prefix)))
-    (if (semantic-tag-p completetext)
-    (setq completetext (semantic-tag-name completetext)))
-
-    (if (and (not completetext) (not desired-type))
-    (error "Nothing to complete"))
-
-    (if (not completetext) (setq completetext ""))
-
-    ;; This better be a reasonable type, or we should fry it.
-    ;; The prefixtypes should always be at least 1 less than
-    ;; the prefix since the type is never looked up for the last
-    ;; item when calculating a sequence.
-    (setq completetexttype (car (reverse prefixtypes)))
-    (when (or (not completetexttype)
-          (not (and (semantic-tag-p completetexttype)
-            (eq (semantic-tag-class completetexttype) 'type))))
-      ;; What should I do here?  I think this is an error condition.
-      (setq completetexttype nil)
-      ;; If we had something that was a completetexttype but it wasn't
-      ;; valid, then express our dismay!
-      (when (> (length prefix) 1)
-    (let* ((errprefix (car (cdr (reverse prefix)))))
-      (error "Cannot find types for `%s'"
-         (cond ((semantic-tag-p errprefix)
-            (semantic-format-tag-prototype errprefix))
-               (t
-            (format "%S" errprefix)))))
-    ))
-
-    ;; There are many places to get our completion stream for.
-    ;; Here we go.
-    (if completetexttype
-
-    (setq c (semantic-find-tags-for-completion
-         completetext
-         (semantic-analyze-scoped-type-parts completetexttype scope)
-         ))
-
-      ;; No type based on the completetext.  This is a free-range
-      ;; var or function.  We need to expand our search beyond this
-      ;; scope into semanticdb, etc.
-      (setq c (nconc
-           ;; Argument list and local variables
-           (semantic-find-tags-for-completion completetext localvar)
-           ;; The current scope
-           (semantic-find-tags-for-completion completetext (when scope 
(oref scope fullscope)))
-           ;; The world
-           (semantic-analyze-find-tags-by-prefix completetext))
-        )
-      )
-
-    (let ((loopc c)
-      (dtname (semantic-tag-name desired-type)))
-
-      ;; Save off our first batch of completions
-      (setq origc c)
-
-      ;; Reset c.
-      (setq c nil)
-
-      ;; Loop over all the found matches, and categorize them
-      ;; as being possible features.
-      (while (and loopc do-typeconstraint)
-
-    (cond
-     ;; Strip operators
-     ((semantic-tag-get-attribute (car loopc) :operator-flag)
-      nil
-      )
-
-     ;; If we are completing from within some prefix,
-     ;; then we want to exclude constructors and destructors
-     ((and completetexttype
-           (or (semantic-tag-get-attribute (car loopc) :constructor-flag)
-           (semantic-tag-get-attribute (car loopc) :destructor-flag)))
-      nil
-      )
-
-     ;; If there is a desired type, we need a pair of restrictions
-     (desired-type
+    (catch 'cant-complete
+      (when (not do-longprefix)
+        ;; If we are not doing the long prefix, shorten all the key
+        ;; elements.
+        (setq prefix (list (car (reverse prefix)))
+          prefixtypes nil))
+
+      ;; Calculate what our prefix string is so that we can
+      ;; find all our matching text.
+      (setq completetext (car (reverse prefix)))
+      (if (semantic-tag-p completetext)
+      (setq completetext (semantic-tag-name completetext)))
+
+      (if (and (not completetext) (not desired-type))
+          (throw 'cant-complete nil)
+      ;;(error "Nothing to complete")
+        )
+
+      (if (not completetext) (setq completetext ""))
+
+      ;; This better be a reasonable type, or we should fry it.
+      ;; The prefixtypes should always be at least 1 less than
+      ;; the prefix since the type is never looked up for the last
+      ;; item when calculating a sequence.
+      (setq completetexttype (car (reverse prefixtypes)))
+      (when (or (not completetexttype)
+            (not (and (semantic-tag-p completetexttype)
+              (eq (semantic-tag-class completetexttype) 'type))))
+        ;; What should I do here?  I think this is an error condition.
+        (setq completetexttype nil)
+        ;; If we had something that was a completetexttype but it wasn't
+        ;; valid, then express our dismay!
+        (when (> (length prefix) 1)
+          (throw 'cant-complete nil)
+;;;      (let* ((errprefix (car (cdr (reverse prefix)))))
+;;;        (error "Cannot find types for `%s'"
+;;;           (cond ((semantic-tag-p errprefix)
+;;;              (semantic-format-tag-prototype errprefix))
+;;;                 (t
+;;;              (format "%S" errprefix)))))
+      ))
+
+      ;; There are many places to get our completion stream for.
+      ;; Here we go.
+      (if completetexttype
+
+      (setq c (semantic-find-tags-for-completion
+           completetext
+           (semantic-analyze-scoped-type-parts completetexttype scope)
+           ))
+
+        ;; No type based on the completetext.  This is a free-range
+        ;; var or function.  We need to expand our search beyond this
+        ;; scope into semanticdb, etc.
+        (setq c (nconc
+             ;; Argument list and local variables
+             (semantic-find-tags-for-completion completetext localvar)
+             ;; The current scope
+             (semantic-find-tags-for-completion completetext (when 
scope (oref scope fullscope)))
+             ;; The world
+             (semantic-analyze-find-tags-by-prefix completetext))
+          )
+        )
+
+      (let ((loopc c)
+        (dtname (semantic-tag-name desired-type)))
+
+        ;; Save off our first batch of completions
+        (setq origc c)
+
+        ;; Reset c.
+        (setq c nil)
+
+        ;; Loop over all the found matches, and categorize them
+        ;; as being possible features.
+        (while (and loopc do-typeconstraint)

        (cond
-       ;; Ok, we now have a completion list based on the text we found
-       ;; we want to complete on.  Now filter that stream against the
-       ;; type we want to search for.
-       ((string= dtname (semantic-analyze-type-to-name 
(semantic-tag-type (car loopc))))
-        (setq c (cons (car loopc) c))
+       ;; Strip operators
+       ((semantic-tag-get-attribute (car loopc) :operator-flag)
+        nil
          )

-       ;; Now anything that is a compound type which could contain
-       ;; additional things which are of the desired type
-       ((semantic-tag-type (car loopc))
-        (let ((att (semantic-analyze-tag-type (car loopc) scope))
-        )
-          (if (and att (semantic-tag-type-members att))
-          (setq c (cons (car loopc) c))))
+       ;; If we are completing from within some prefix,
+       ;; then we want to exclude constructors and destructors
+       ((and completetexttype
+             (or (semantic-tag-get-attribute (car loopc) :constructor-flag)
+             (semantic-tag-get-attribute (car loopc) :destructor-flag)))
+        nil
          )

-       ) ; cond
-      ); desired type
-
-     ;; No desired type, no other restrictions.  Just add.
-     (t
-      (setq c (cons (car loopc) c)))
-
-     ); cond
-
-    (setq loopc (cdr loopc)))
-
-      (when desired-type
-    ;; Some types, like the enum in C, have special constant values that
-    ;; we could complete with.  Thus, if the target is an enum, we can
-    ;; find possible symbol values to fill in that value.
-    (let ((constants
-           (semantic-analyze-type-constants desired-type)))
-      (if constants
-          (progn
-        ;; Filter
-        (setq constants
-              (semantic-find-tags-for-completion
-               completetext constants))
-        ;; Add to the list
-        (setq c (nconc c constants)))
-        )))
-      )
-
-    (when desired-class
-      (setq c (semantic-analyze-tags-of-class-list c desired-class)))
-
-    (if do-unique
-    (if c
-        ;; Pull out trash.
-        ;; NOTE TO SELF: Is this too slow?
-        (setq c (semantic-unique-tag-table-by-name c))
-      (setq c (semantic-unique-tag-table-by-name origc)))
-      (when (not c)
-    (setq c origc)))
-
-    ;; All done!
-    c))
+       ;; If there is a desired type, we need a pair of restrictions
+       (desired-type
+
+        (cond
+         ;; Ok, we now have a completion list based on the text we found
+         ;; we want to complete on.  Now filter that stream against the
+         ;; type we want to search for.
+         ((string= dtname (semantic-analyze-type-to-name 
(semantic-tag-type (car loopc))))
+          (setq c (cons (car loopc) c))
+          )
+
+         ;; Now anything that is a compound type which could contain
+         ;; additional things which are of the desired type
+         ((semantic-tag-type (car loopc))
+          (let ((att (semantic-analyze-tag-type (car loopc) scope))
+            )
+            (if (and att (semantic-tag-type-members att))
+            (setq c (cons (car loopc) c))))
+          )
+
+         )                          ; cond
+        )                           ; desired type
+
+       ;; No desired type, no other restrictions.  Just add.
+       (t
+        (setq c (cons (car loopc) c)))
+
+       )                            ; cond
+
+      (setq loopc (cdr loopc)))
+
+        (when desired-type
+      ;; Some types, like the enum in C, have special constant values that
+      ;; we could complete with.  Thus, if the target is an enum, we can
+      ;; find possible symbol values to fill in that value.
+      (let ((constants
+             (semantic-analyze-type-constants desired-type)))
+        (if constants
+            (progn
+          ;; Filter
+          (setq constants
+                (semantic-find-tags-for-completion
+                 completetext constants))
+          ;; Add to the list
+          (setq c (nconc c constants)))
+          )))
+        )
+
+      (when desired-class
+        (setq c (semantic-analyze-tags-of-class-list c desired-class)))
+
+      (if do-unique
+      (if c
+          ;; Pull out trash.
+          ;; NOTE TO SELF: Is this too slow?
+          (setq c (semantic-unique-tag-table-by-name c))
+        (setq c (semantic-unique-tag-table-by-name origc)))
+        (when (not c)
+      (setq c origc)))
+
+      ;; All done!
+      c)))

  (provide 'semantic/analyze/complete)