From 8ffd4df1fa7a2a7e0577c54ff6f9af0610d1d282 Mon Sep 17 00:00:00 2001
From: druckdev <druckdev@protonmail.com>
Date: Thu, 20 Jan 2022 16:05:47 +0100
Subject: [PATCH] vim:keys: Add insert mappings for better undo

The bigger `inoremap <expr> ...` binding is taken from the help page
`:help i_ctrl-g_u`.
---
 .config/vim/vimrc.d/40-keys.vim | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/.config/vim/vimrc.d/40-keys.vim b/.config/vim/vimrc.d/40-keys.vim
index a3aa9e5..5f5003b 100644
--- a/.config/vim/vimrc.d/40-keys.vim
+++ b/.config/vim/vimrc.d/40-keys.vim
@@ -130,3 +130,22 @@ inoremap <silent> <A-Down> <Esc>:m .+1<CR>==gi
 " Fix & command to also use last flags
 nnoremap & :&&<CR>
 xnoremap & :&&<CR>
+
+" see :help i_ctrl-g_u
+" Do not break undo sequence when using the arrow keys or home and end in insert
+" mode
+inoremap <Left>  <C-G>U<Left>
+inoremap <Right> <C-G>U<Right>
+inoremap <expr> <Home> col('.') == match(getline('.'), '\S') + 1 ?
+	\ repeat('<C-G>U<Left>', col('.') - 1) :
+	\ (col('.') < match(getline('.'), '\S') ?
+	\     repeat('<C-G>U<Right>', match(getline('.'), '\S') + 0) :
+	\     repeat('<C-G>U<Left>', col('.') - 1 - match(getline('.'), '\S')))
+inoremap <expr> <End> repeat('<C-G>U<Right>', col('$') - col('.'))
+" Make insert-mode texts repeatable by `.` with the closing parentheses at the
+" right position
+inoremap ( ()<C-G>U<Left>
+" break undo sequence with every space and newline, making insert mode changes
+" revertible in smaller chunks
+inoremap <Space> <C-G>u<Space>
+inoremap <CR> <C-G>u<CR>