How to go to the nth-to-last character in insert mode?

Question

Capital A in Vim takes me to the last character in insert mode, but can I go to the nth-to-last character in insert mode (or append mode) in vim?

Example:

this is some t|ext

how to go specifically to the location of the | in insert mode, I would imagine something like <n>+A where n is an integer. I did see a similar question here: how-to-go-to-before-last-character-in-a-line and an answer suggested to use $i, to go to the second-to-last character in insert mode, but this can't go to the nth character.

[Edit]:

I only want to end up in insert mode, not necessarily do all the commands in insert mode but rather do them in normal mode.

Answer 1

I concocted a script that does what you want. I think it handles most corner cases, however you might find some bugs down the road if you decide to use it.

function! AWithCount(count) abort
  " default behaviour (no count)
  if !a:count
    "append to end of line, like `A`
    startinsert!
    return
  endif

  " line too short for `count` (`:h col())
  " `col('$')` => length of current line
  if col('$') - 1 < a:count
    " go to first non-whitespace, or to start if only whitespaces
    " -> `normal 0` / `normal _`
    " `:h =~` `:h trinary`
    normal (getline('.') =~ "^\\s\\+$") ? "0" : "_"
    startinsert
    return
  endif

  " place cursor and enter insert mode
  " -> `$X<left><right>`, X a number
  " `:h :exe`
  exe "normal $" . a:count . "\<left>\<right>"
  startinsert
endfunction

" `:h <silent>` to avoid clutter in the command line
" <c-u> to clear things vim puts in command line
nnoremap <silent> A :<c-u>call AWithCount(v:count)<cr>

Answer 2

<ALT-$> [count] hi where [count] is a number

1. the Alt key to enter commands while in insert mode
2. while pressing the Alt key press "$" to go to end of line
3. press [count] "h" to go left [count] times
4. press i to go into insert mode