occur-x.el adds some extra functionality to occur-mode.  It allows the
user to refine any occur mode with extra regexp based filters.  Use
commands `occur-x-filter-out' and `occur-x-filter' to add positive and
negative filters.  By default those commands are bind to keys "f" and
"k" (from flush and keep).  Use command `occur-x-undo-filter' to remove
filters.  Filters are kept if the buffer is reverted (shortcut "g") or
cloned (shortcut "c").

Another useful addition of occur-x to occur-mode is the possibility to
displaying the line numbers in the margin of your choice, instead of
"inside" the occur buffer.  This way every match line in the occur
buffer is exactly the same as in the original buffer.  Customize
variable `occur-linenumbers-in-margin' and face `occur-margin-face' to
your liking.  When displayed in the margin, line numbers won't interfere
with the regexps of the additional filters.

Usage

Put this file in your load-path and add this lines to your init file:

(require 'occur-x)
(add-hook 'occur-mode-hook 'turn-on-occur-x-mode)

Feedback

Bugs reports, comments, ideas, etc. welcomed.

https://github.com/juan-leon/occur-x