feat(segments): buffer-identification now prepends path

Adds new custom variable
`whale-line-segments-buffer-identification-path-segments` and sets it
to 1. This is the number of preceding path segments that are included
in the segment.

If the old behavior is desired, this can be set to 0.

README.org

@@ -132,6 +132,9 @@ the change.
                                              ])
   (whale-line-segments-animation-speed 0.4)
 
+  ;; Buffer identification.
+  (whale-line-segments-buffer-identification-path-segments 1)
+
   ;; Org.
   (whale-line-segments-org-separator ">")
   (whale-line-segments-org-ellispis "…")

test/whale-line-segments-test.el

@@ -27,17 +27,38 @@
       (bydi-was-called-with run-hooks 'whale-line-segments-buffer-identification-hook))))
 
 (ert-deftest buffer-identification ()
-  (should (equal '((:propertize (:eval (propertized-buffer-identification "%b"))
+  (should (equal '((:propertize (:eval (whale-line-segments--buffer-identification--path-segments))
+                                face whale-line-shadow)
+                   (:propertize (:eval (propertized-buffer-identification "%b"))
                                 face (mode-line-buffer-id nil)))
                  (whale-line-segments--buffer-identification)))
 
   (let ((whale-line-segments--buffer-identification--additional-help "help"))
 
-    (should (equal '((:propertize (:eval (propertized-buffer-identification "%b"))
+    (should (equal '((:propertize (:eval (whale-line-segments--buffer-identification--path-segments))
+                 face whale-line-shadow)
+                     (:propertize (:eval (propertized-buffer-identification "%b"))
                                   face (mode-line-buffer-id nil)
                                   help-echo "help"))
                    (whale-line-segments--buffer-identification)))))
 
+(ert-deftest buffer-identification--path-segments ()
+  :tags '(segments buffer)
+
+  (bydi ((:mock buffer-file-name :return "/test/one/two/three.el"))
+
+    (let ((whale-line-segments-buffer-identification-path-segments 1))
+
+      (should (string= "two/" (whale-line-segments--buffer-identification--path-segments)))
+
+      (setq whale-line-segments-buffer-identification-path-segments 12)
+
+      (should (string= "/test/one/two/" (whale-line-segments--buffer-identification--path-segments)))
+
+      (setq whale-line-segments-buffer-identification-path-segments 0)
+
+      (should-not (whale-line-segments--buffer-identification--path-segments)))))
+
 (ert-deftest buffer-status--using-icons ()
   (let ((modified nil)
         (buffer-file-name "some-name"))

whale-line-segments.el

@@ -67,6 +67,13 @@ to 2, only the 3rd level is elided."
   :group 'whale-line-segments
   :type 'integer)
 
+(defcustom whale-line-segments-buffer-identification-path-segments 1
+  "The amount of path elements to show before buffer identification.
+
+This can be disabled by setting this to 0."
+  :group 'whale-line-segments
+  :type 'integer)
+
 ;;;; Utility
 
 (defun whale-line-segments--decorate (_symbol &rest _args)
@@ -99,12 +106,27 @@ See `whale-line-iconify' for a way to do this."
   (run-hooks 'whale-line-segments-buffer-identification-hook))
 
 (defun whale-line-segments--buffer-identification ()
-  "Get the buffer identification."
-  `((:propertize (:eval (propertized-buffer-identification "%b"))
+  "Get the buffer identification.
+
+This pre-pends the path to the buffer if so configured."
+  `((:propertize (:eval (whale-line-segments--buffer-identification--path-segments))
+                 face whale-line-shadow)
+    (:propertize (:eval (propertized-buffer-identification "%b"))
                  face ,(list 'mode-line-buffer-id whale-line-segments--buffer-identification--additional-face)
                  ,@(and whale-line-segments--buffer-identification--additional-help
                         (list 'help-echo whale-line-segments--buffer-identification--additional-help)))))
 
+(defun whale-line-segments--buffer-identification--path-segments ()
+  "Get preceding path segments."
+  (when (> whale-line-segments-buffer-identification-path-segments 0)
+
+    (let* ((file (buffer-file-name (current-buffer)))
+           (path (file-name-split file))
+           (count (min (1- (length path)) whale-line-segments-buffer-identification-path-segments))
+           (segments (seq-take (cdr (reverse path)) count)))
+
+      (concat (string-join (reverse segments) "/") "/"))))
+
 (whale-line-create-stateful-segment buffer-identification
   :getter whale-line-segments--buffer-identification
   :hooks (find-file-hook after-save-hook clone-indirect-buffer-hook kill-buffer-hook whale-line-segments-buffer-identification-hook)