From 796ffd9e34bd5208048d1b5062c09022ed57de62 Mon Sep 17 00:00:00 2001
From: Michiel Scholten <michiel@diginaut.net>
Date: Mon, 29 Sep 2025 14:56:19 +0200
Subject: [PATCH] Toggle casing

---
 .vimrc | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/.vimrc b/.vimrc
index 7f8c38a..481cd4c 100644
--- a/.vimrc
+++ b/.vimrc
@@ -586,6 +586,21 @@ fun! TrimWhitespace()
 endfun
 command! TrimWhitespace call TrimWhitespace()
 
+" Visually select text then press ~ to convert the text to UPPER CASE, then to lower case, then to Title Case.
+" Keep pressing ~ until you get the case you want.
+" https://vim.fandom.com/wiki/Switching_case_of_characters
+function! TwiddleCase(str)
+  if a:str ==# toupper(a:str)
+    let result = tolower(a:str)
+  elseif a:str ==# tolower(a:str)
+    let result = substitute(a:str,'\(\<\w\+\>\)', '\u\1', 'g')
+  else
+    let result = toupper(a:str)
+  endif
+  return result
+endfunction
+vnoremap ~ y:call setreg('', TwiddleCase(@"), getregtype(''))<CR>gv""Pgv
+
 " enable words completion
 set dictionary+=/usr/share/dict/words
 " use ctrl-n ctrl-n instead of ctrl-x ctrl-k