MelBurslan is correct that this feature does not natively exist, but creating a user-defined command is not really the way to go about creating it. I tinkered for a few minutes and came up with this:
:nmap <silent> ,s "=nr2char(getchar())<cr>P
Which uses some Vim trickery involving "putting" text from a register, in this case the "expression" register. The expression being plugged into the register is "nr2char(getchar())
" which will return a single character string.
The reason I built the mapping this way is that getting user input "midway through" a mapping is tricky and can behave unpredictably; even this mapping will drop the cursor down to the status area while waiting for the user to type a character.
See http://vim.wikia.com/wiki/Insert_a_single_character for comprehensive solution.
– Maxim Suslov – 2018-09-07T07:40:29.5601
Possible cross site duplicate: http://stackoverflow.com/questions/1557893/making-inserting-a-single-character-in-vim-an-atomic-operation
– Ciro Santilli 新疆改造中心法轮功六四事件 – 2014-01-23T14:12:33.137