1 files changed, 33 insertions, 0 deletions
diff --git a/sx.el b/sx.el
index 33b36b6..0ea8e4d 100644
--- a/sx.el
+++ b/sx.el
@@ -419,6 +419,39 @@ if ALIST contains a different string at the ?% entry."
       (buffer-string))))
 
 
+;;; Key definitions
+(defun sx--key-definitions-to-header-line (definitions)
+  "Return a `header-line-format' from DEFINITIONS.
+DEFINITIONS is a list where each element has one of the following two forms
+    (KEY COMMAND)
+    (KEY COMMAND DESCRIPTION)
+
+The latter are used to build the return value, the former are
+ignored."
+  (let ((ptize (lambda (x) `(:propertize ,x face mode-line-buffer-id)))
+        alist out)
+    (dolist (it definitions)
+      (when (> (length it) 2)
+        (let* ((key (car it))
+               (desc (elt it 2))
+               (cell (assoc desc alist)))
+          (if cell (push key (cdr cell))
+            (push (cons desc (list key)) alist)))))
+    (dolist (it alist out)
+      (let ((desc (car it))
+            (keys (cdr it)))
+        (push (list "   "
+                    (cons (funcall ptize (car keys))
+                          (mapcar (lambda (k) `("," ,(funcall ptize k))) (cdr keys)))
+                    (let ((match
+                           (and (= 1 (length keys))
+                                (string-match (regexp-quote (car keys)) desc))))
+                      (if (and (numberp match) (= 0 match))
+                          (substring desc (length (car keys)))
+                        (concat ":" desc))))
+              out)))))
+
+
 (defcustom sx-init-hook nil
   "Hook run when SX initializes.
 Run after `sx-init--internal-hook'."