From 9e0338e6836dc33f8204f613b9bcb4af433b04db Mon Sep 17 00:00:00 2001
From: Daniel Borchmann <daniel@algebra20.de>
Date: Fri, 20 Dec 2019 16:12:11 +0100
Subject: [PATCH] Dynamically create hydra from `db/frequently-used-features'

---
 init.el                | 12 ++++++++----
 site-lisp/db-hydras.el | 23 ++++++++++++++++++-----
 2 files changed, 26 insertions(+), 9 deletions(-)

diff --git a/init.el b/init.el
index 968e594..2c78663 100644
--- a/init.el
+++ b/init.el
@@ -169,8 +169,7 @@
   (bind-key "<XF86Back>" #'winner-undo)
   (bind-key "<XF86Forward>" #'winner-redo)
   (bind-key "<f1>" #'db/run-or-hide-eshell)
-  (bind-key "<f2> i" #'counsel-info-lookup-symbol)
-  (bind-key "<f2> u" #'counsel-unicode-char)
+  (bind-key "<f2>" #'hydra-shortcuts/body)
   (bind-key "<f5>" #'rgrep)
   (bind-key "<f6>" #'hydra-zoom/body)
   (bind-key "<f7>" #'dictcc)
@@ -591,7 +590,9 @@
 (use-package db-hydras
   :commands (hydra-toggle/body
              hydra-zoom/body
-             hydra-rectangle/body))
+             hydra-rectangle/body
+             hydra-shortcuts/body
+             db/define-hydra-from-frequently-used-features))
 
 (use-package git-commit
   :commands (global-git-commit-mode))
@@ -657,7 +658,10 @@ them.  Can be used in application shortcuts such as
 short description, a shortcut character, and the function to
 call."
   :group 'personal-settings
-  :type  '(repeat (list string character function)))
+  :type  '(repeat (list string character function))
+  :set   #'(lambda (symbol value)
+             (set symbol value)
+             (db/define-hydra-from-frequently-used-features)))
 
 (defcustom db/important-documents-path "~/Documents/library/"
   "Path to look for documents that can be listed in extended
diff --git a/site-lisp/db-hydras.el b/site-lisp/db-hydras.el
index d62f05c..4e63350 100644
--- a/site-lisp/db-hydras.el
+++ b/site-lisp/db-hydras.el
@@ -6,9 +6,6 @@
 
 (require 'hydra)
 
-
-;;; Hydras
-
 (defhydra hydra-toggle (:color blue)
   "toggle"
   ("c" column-number-mode "column")
@@ -53,8 +50,24 @@ _h_   _l_   _o_k        _y_ank
   ("e" rectangle-exchange-point-and-mark nil)
   ("o" nil nil))
 
-
-;; End
+(defun hydra-shortcuts/body ()
+  "Dummy default value for shortcuts hydra.  Will simply barf."
+  (interactive)
+  (user-error "Shortcuts Hydra not defined yet."))
+
+(defun db/define-hydra-from-frequently-used-features ()
+  "Defines `hydra-shortcuts/body' based on the current value of
+`db/frequently-used-features'.  Raises an error if the latter is
+not bound."
+  (if (not (boundp 'db/frequently-used-features))
+      (user-error "Variable `db/frequently-used-features' is not defined, please set that variable first.")
+    (eval
+     `(defhydra hydra-shortcuts (:color blue)
+        ""
+        ,@(mapcar (lambda (entry)
+                    (pcase-let ((`(,description ,shortcut ,function) entry))
+                      (list (string shortcut) function description)))
+                  db/frequently-used-features)))))
 
 (provide 'db-hydras)
 ;; db-hydras.el ends here