Add racket-pdb-{next previous}-use commands

racket-pdb.el

@@ -31,11 +31,8 @@
 
 (defvar racket-pdb-control-c-hash-keymap
   (racket--easy-keymap-define
-   `(
-     ;; ("j" ,#'racket-pdb-next-definition)
-     ;; ("k" ,#'racket-pdb-previous-definition)
-     ;; ("n" ,#'racket-pdb-next-use)
-     ;; ("p" ,#'racket-pdb-previous-use)
+   `(("n" ,#'racket-pdb-next-use)
+     ("p" ,#'racket-pdb-previous-use)
      ("." ,#'xref-find-definitions)
      ("?" ,#'xref-find-references)
      ("r" ,#'racket-pdb-rename)
@@ -534,6 +531,45 @@ Uses pdb to query for sites among multiple files."
       (_
        (racket--doc prefix path racket--xp-binding-completions)))))
 
+;;; Next/previous use
+
+(defun racket--pdb-def-or-use-overlay-at (pos)
+  (seq-some (lambda (o)
+              (and (memq (overlay-get o 'face)
+                         '(racket-xp-def-face racket-xp-use-face))
+                   o))
+            (overlays-at pos)))
+
+(defun racket-pdb-next-use ()
+  "When point is a highlighted definition or use, go to the next related site."
+  (interactive)
+  (when-let (o (racket--pdb-def-or-use-overlay-at (point)))
+    (let ((pos (overlay-end o)))
+      (catch 'exit
+        (while t
+          (setq pos (next-overlay-change pos))
+          (when (= pos (point-max))
+            (throw 'exit nil))
+          (when-let (o (racket--pdb-def-or-use-overlay-at pos))
+            (goto-char (overlay-start o))
+            (throw 'exit nil))
+          (incf pos))))))
+
+(defun racket-pdb-previous-use ()
+  "When point is a highlighted definition or use, go to the previous related site."
+  (interactive)
+  (when-let (o (racket--pdb-def-or-use-overlay-at (point)))
+    (let ((pos (overlay-start o)))
+      (catch 'exit
+        (while t
+          (setq pos (previous-overlay-change pos))
+          (when (= pos (point-min))
+            (throw 'exit nil))
+          (when-let (o (racket--pdb-def-or-use-overlay-at pos))
+            (goto-char (overlay-start o))
+            (throw 'exit nil))
+          (decf pos))))))
+
 ;;; Mode line status
 
 (defvar-local racket--pdb-mode-status nil)