can copy project relative path of current buffer

lisp/init-clipboard.el

@@ -16,12 +16,33 @@ If N is not nil, copy file name and line number."
       (message "%s => clipboard&kill-ring" s))))
 
 (defun cp-fullpath-of-current-buffer ()
-  "Copy full path into the yank ring and OS clipboard"
+  "Copy full path into the yank ring and OS clipboard."
   (interactive)
   (when buffer-file-name
     (copy-yank-str (file-truename buffer-file-name))
     (message "file full path => clipboard & yank ring")))
 
+(defun cp-root-relative-path-of-current-buffer ()
+  "Copy path relative to the project root into the yank ring and OS clipboard"
+  (interactive)
+  (when buffer-file-name
+    ;; require ffip to get project root
+    (my-ensure 'find-file-in-project)
+    (let* ((root (ffip-project-root))
+           (file-path (file-truename buffer-file-name))
+           relative-path)
+      (cond
+       ((not root)
+        (message "Can't find project root."))
+
+       ((not file-path)
+        (message "File path of current buffer is empty."))
+
+       (t
+        (setq relative-path (file-relative-name file-path root))
+        (copy-yank-str relative-path)
+        (message "%s => clipboard & yank ring" relative-path))))))
+
 (defun clipboard-to-kill-ring ()
   "Copy from clipboard to `kill-ring'."
   (interactive)

lisp/init-evil.el

@@ -614,6 +614,7 @@ If N > 0 and in js, only occurrences in current N lines are renamed."
   "kc" 'kill-ring-to-clipboard
   "fn" 'cp-filename-of-current-buffer
   "fp" 'cp-fullpath-of-current-buffer
+  "rp" 'cp-root-relative-path-of-current-buffer
   "dj" 'dired-jump ;; open the dired from current file
   "xo" 'ace-window
   "ff" 'my-toggle-full-window ;; I use WIN+F in i3