How to count characters while typing? - vim

Question

I often use VIM to write comments in newspapers or blog sites.
Often there is a max number of characters to type.
How do I create a counter (p.e. in the statusbar) to see the characters I have typed (including whitespaces) while typing?

Answer 1

The 'statusline' setting allows evaluation of expressions with the %{...} special item.
So if we can come up with an expression that returns the number of characters (not bytes!) in the current buffer we can incorporate it in our statusline to solve the problem.
This command does it:
:set statusline+=\ %{strwidth(join(getline(1,'$'),'\ '))}
For text with CJK characters strwidth() is not good enough, since it returns a display cell count, not a character count. If double-width characters are part of the requirement, use this improved version instead:
:set statusline+=\ %{strlen(substitute(join(getline(1,'$'),'.'),'.','.','g'))}
But be aware that the expression is evaluated on every single change to the buffer.
See :h 'statusline'.
Sunday afternoon bonus – The character position under the cursor can also be packed into a single expression. Not for the faint of heart:
:set statusline+=\ %{strlen(substitute(join(add(getline(1,line('.')-1),strpart(getline('.'),0,col('.')-1)),'.'),'.','.','g'))+1}

Answer 2

By mixing glts answer and this post and a bit of fiddling with the code, I made the following for my self which you can put it in ~/.vimrc file (you need to have 1 second idol cursor so the function calculates the words and characters and the value can be changed by modifying set updatetime=1000):
let g:word_count = "<unknown>"
let g:char_count = "<unknown>"
function WordCount()
return g:word_count
endfunction
function CharCount()
return g:char_count
endfunction
function UpdateWordCount()
let lnum = 1
let n = 0
while lnum <= line('$')
let n = n + len(split(getline(lnum)))
let lnum = lnum + 1
endwhile
let g:word_count = n
let g:char_count = strlen(substitute(join(getline(1,'$'),'.'),'.','.','g'))
endfunction
" Update the count when cursor is idle in command or insert mode.
" Update when idle for 1000 msec (default is 4000 msec).
set updatetime=1000
augroup WordCounter
au! CursorHold,CursorHoldI * call UpdateWordCount()
augroup END
" Set statusline, shown here a piece at a time
highlight User1 ctermbg=green guibg=green ctermfg=black guifg=black
set statusline=%1* " Switch to User1 color highlight
set statusline+=%<%F " file name, cut if needed at start
set statusline+=%M " modified flag
set statusline+=%y " file type
set statusline+=%= " separator from left to right justified
set statusline+=\ %{WordCount()}\ words,
set statusline+=\ %{CharCount()}\ chars,
set statusline+=\ %l/%L\ lines,\ %P " percentage through the file
It will look like this: