Determine if the cursor is on the first/last character of word

Question

How to determine if the cursor is placed on the last character of the word under the cursor?

I can get information about the word under cursor like determining if the length of the word under the cursor is 1 character:

strlen(expand('<cword>'))==1

But as far as I see the expression expand('<cword>') only returns the word itself with no information about the cursor position.

Any help pointing towards a potential solution is appreciated.

Answer 1

I'd take a more experimental approach that @Karl Yngve Lervåg does in his answer:

This works by moving the cursor back a word and then forwards again and then seeing if the cursor is in the same place. If it is, then the cursor was on the end of a <word>.

Using this technique saves you having to reverse-engineer and reimplement Vim's <word> algorithm in VimScript.

function! EndWord() abort
  let pos = getpos('.')
  normal! gee
  if pos == getpos('.')
    return v:true
  else
    call setpos('.', pos)
    return v:false
  endif
endfunction

Answer 2

I would get the characters on the current line from the cursor and on and check if they match the end-of-word atom, i.e. something like this:

map <silent> q :call Test()<cr>

function! Test() abort
  return strcharpart(getline('.'), virtcol('.')-1, 3) =~# '^\w\>'
endfunction

Here I've added a map for making it easy to test. You can adjust the function, resource the file and then use q to test the function.

I use virtcol and strcharpart to support multibyte characters.