Install the loccur package

configuration.org

@@ -2134,6 +2134,25 @@ This will be replaced with something self-hosted, eventually.
   (editorconfig-mode t))
 #+END_SRC
 
+** occur-like folding in the current buffer
+
+#+BEGIN_SRC emacs-lisp
+(defun gpolonkai/toggle-loccur ()
+  "Toggle `loccur-mode'.
+
+If `loccur-mode' is not active, starts it (which, in turn, will ask for the
+pattern to look for).  If it is active, it will disable it."
+  (interactive)
+  (if loccur-mode
+      (loccur-mode nil)
+    (call-interactively 'loccur)))
+
+(use-package loccur
+  :bind
+  (:map gpolonkai/pers-map
+   ("C-o" . gpolonkai/toggle-loccur)))
+#+END_SRC
+
 * Make programming a bit easier
 
 ** Electric case

customizations.el

@@ -124,6 +124,7 @@
      js2-mode
      json-mode
      kanban
+     loccur
      lorem-ipsum
      magit
      magit-gerrit