Creates a keybinding that links to the most recently edited file of a directory.

insert-newest-link.el

(defun ms-filter-dirs (filelist)
  (remove-if (lambda (file) (file-directory-p file)) filelist))
(defun ms-newest-file (dir)
  (reduce (lambda (accum file)
            (if (file-newer-than-file-p file accum)
                file
              accum))
          (ms-filter-dirs (directory-files dir t))))
(defun ms-insert-newest-file (dir)
  (lexical-let ((dir dir))
    (lambda ()
      (interactive)
      (org-insert-link :link-location (concat "file:"
                                              (ms-newest-file dir))))))

(global-set-key (kbd "C-c C-S-l") (ms-insert-newest-file "~/Downloads"))

hi - I think this is exactly what I need! unfortunately executing results in 'Symbol's function definition is void: lexical-let"
With debugger 'on':
Debugger entered--Lisp error: (void-function lexical-let)
EDIT - just found out I needed to add (require 'cl)

Yeah, that's part of cl. All it's doing is allowing that dir parameter from ms-insert-newest-file to be used in the lambda function it's returning. You can see in the initial gist I used to just create the function in global-set-key. You can do that if you don't want to include cl.

I'm going to remove the relative filename conversion and append "file:" to the link, that should put the generated link in the correct format.