Add function to eshell config that shortens directory names

This function isn't being used yet.

oni-eshell.el

@@ -4,7 +4,7 @@
 
 ;; Author: Tom Willemse <tom@ryuslash.org>
 ;; Keywords: local
-;; Version: 2020.1106.164034
+;; Version: 2020.1210.213125
 ;; Package-Requires: (eshell-fringe-status esh-autosuggest xterm-color eshell-syntax-highlighting)
 
 ;; This program is free software; you can redistribute it and/or modify
@@ -81,6 +81,24 @@
   (eshell/cd (file-name-directory (buffer-file-name (get-buffer buffer-name))))
   (eshell-reset))
 
+(defun oni-eshell-shorten-directories (path)
+  "Shorten PATH to a list of unique shortened directory names."
+  (let* ((directories (split-string path "/" t))
+         (new-path
+          (string-join
+           (mapcar (lambda (d)
+                     (let ((name (substring d 0 1))
+                           (length 1))
+                       (while (cl-find-if (lambda (s) (and (not (string= s d))
+                                                           (string-prefix-p name s)))
+                                          directories)
+                         (setq name (substring d 0 (cl-incf length))))
+                       name))
+                   directories) "/")))
+    (if (string-prefix-p "~" new-path)
+        new-path
+      (concat "/" new-path))))
+
 (add-hook 'eshell-before-prompt-hook #'oni-eshell--set-xterm-variables)
 (add-hook 'eshell-first-time-mode-hook #'oni-eshell--expand-keymap)
 (add-hook 'eshell-load-hook #'oni-eshell--disable-ansi-color-handling)