Insert Single Character in Vim?
Thanks to Johnny for giving us this terrific answer in the comments below:
":nmap <C-i> i_<Esc>r"
That maps Control + i to insert a single character, and it does it very concisely.
In your vimrc file, this will look like:
nnoremap <C-i> i_<Esc>r
I changed my mapping to use space, and you can change yours to your preferred key(s):
nnoremap <Space> i_<Esc>r
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.
As far as I know, there is no such function in any widely distributed incarnation of vi editor but, vim has a facility to create custom commands. It has previously been discussed here: in this thread
You might be able to create your custom command doing what you wish to do.