[completion] Cache last result of cider-complete

Author: alexander-yakushev

cider-completion.el

@@ -184,26 +184,34 @@ performed by `cider-annotate-completion-function'."
   (when-let* ((bounds (bounds-of-thing-at-point 'symbol)))
     (when (and (cider-connected-p)
                (not (or (cider-in-string-p) (cider-in-comment-p))))
-      (list (car bounds) (cdr bounds)
-            (lambda (prefix pred action)
-              ;; When the 'action is 'metadata, this lambda returns metadata about this
-              ;; capf, when action is (boundaries . suffix), it returns nil. With every
-              ;; other value of 'action (t, nil, or lambda), 'action is forwarded to
-              ;; (complete-with-action), together with (cider-complete), prefix and pred.
-              ;; And that function performs the completion based on those arguments.
-              ;;
-              ;; This api is better described in the section
-              ;; '21.6.7 Programmed Completion' of the elisp manual.
-              (cond ((eq action 'metadata) `(metadata (category . cider))) ;; defines a completion category named 'cider, used later in our `completion-category-overrides` logic.
-                    ((eq (car-safe action) 'boundaries) nil)
-                    (t (with-current-buffer (current-buffer)
-                         (complete-with-action action
-                                               (cider-complete prefix) prefix pred)))))
-            :annotation-function #'cider-annotate-symbol
-            :company-kind #'cider-company-symbol-kind
-            :company-doc-buffer #'cider-create-compact-doc-buffer
-            :company-location #'cider-company-location
-            :company-docsig #'cider-company-docsig))))
+      (let* (last-prefix
+             last-result
+             (complete
+              (lambda (prefix)
+                (unless (string-equal last-prefix prefix)
+                  (setq last-prefix prefix)
+                  (setq last-result (cider-complete prefix)))
+                last-result)))
+        (list (car bounds) (cdr bounds)
+              (lambda (prefix pred action)
+                ;; When the 'action is 'metadata, this lambda returns metadata about this
+                ;; capf, when action is (boundaries . suffix), it returns nil. With every
+                ;; other value of 'action (t, nil, or lambda), 'action is forwarded to
+                ;; (complete-with-action), together with (cider-complete), prefix and pred.
+                ;; And that function performs the completion based on those arguments.
+                ;;
+                ;; This api is better described in the section
+                ;; '21.6.7 Programmed Completion' of the elisp manual.
+                (cond ((eq action 'metadata) `(metadata (category . cider))) ;; defines a completion category named 'cider, used later in our `completion-category-overrides` logic.
+                      ((eq (car-safe action) 'boundaries) nil)
+                      (t (with-current-buffer (current-buffer)
+                           (complete-with-action action
+                                                 (funcall complete prefix) prefix pred)))))
+              :annotation-function #'cider-annotate-symbol
+              :company-kind #'cider-company-symbol-kind
+              :company-doc-buffer #'cider-create-compact-doc-buffer
+              :company-location #'cider-company-location
+              :company-docsig #'cider-company-docsig)))))
 
 (defun cider-completion-flush-caches ()
   "Force Compliment to refill its caches.