Why this function to change relative number in lines is not working?

Question

I have found this very useful function to turn on and off relative number lines:

function! NumberToggle()
  if(&relativenumber == 1)
    set number
  else
    set relativenumber
  endif
endfunc

but it doesn't work, when I launch it

:call NumberToggle()

I see no changes, even when I close and reopen vim.

The source of the function is here with other useful related tricks.

Answer 1

The intention of the function as described in the blog post is not to toggle relativenumber but to switch between the number and relativenumber settings.

In Vim 7.3, the number and relativenumber settings could not be used at the same time, and I believe setting one automatically unset the other.

However, as of Vim 7.4, you can enable both settings at the same time. Doing so will use the absolute line number for the current line, and relative line numbers for all other lines.

If you don't wish to do this, and do in fact want to switch between using relative line numbers everywhere or absolute line numbers everywhere, you can amend the function accordingly:

function! NumberToggle()
  if(&relativenumber == 1)
    set number
    set norelativenumber
  else
    set nonumber
    set relativenumber
  endif
endfunc

Alternatively, you could just leave number on at all times, and just toggle relativenumber, which, as grodzik has explained, you can do with a simple: set relativenumber!. This will switch between displaying absolute line numbers everywhere, and displaying it only on the current line (with relative numbers elsewere).

Answer 2

Why won't you use Vim's builtin feature to toggle that? Just use: set relativenumber! - this will cycle between on and off.