Emacs Init: isearch Whitespace Regex

In emacs isearch (Alt+x isearch-forward) [see Emacs: Search Text in Current File] , you can type a space and it will also search for hyphen - and low line _ and tab and newline.

This this very convenient.

Put this in your Emacs Init File:

;; for isearch-forward, make these equivalent: space newline tab hyphen underscore
(setq search-whitespace-regexp "[-_ \t\n]+")

But sometimes you want literal. This command makes it easy to toggle.

(defun xah-toggle-search-whitespace ()
  "Set `search-whitespace-regexp' to nil or includes hyphen lowline tab newline.

URL `http://xahlee.info/emacs/emacs/emacs_isearch_space.html'

Created: 2019-02-22
Version 2024-06-16"
  (interactive)
  (if search-whitespace-regexp
      (progn
        (setq search-whitespace-regexp nil)
        (message "search-whitespace-regexp set to nil."))
    (progn
      (setq search-whitespace-regexp "[-_ \t\n]+")
      (message "search-whitespace-regexp set to hyphen lowline whitespace"))))