Vim: Calling a custom function from set statusline in vimrc

Question

I'm trying to implement the vim script from the book Learning vi and vim on page 202. The following function works, but when I try to use statusline to call it I get the following error:

$ vim
$ Error detected while processing /Users/me/.vimrc:
E518: Unknown option: \ %{SetTimeOfDayColors()}

Here's the vim script (it's currently in my .vimrc)

function SetTimeOfDayColors()
    let currentHour = strftime("%H")
    echo "currentHour is " . currentHour
    if currentHour < 6 + 0
      let colorScheme = "darkblue"
    elseif currentHour < 12 + 0
      let colorScheme = "morning"
    elseif currentHour < 18 + 0
      let colorScheme = "shine"
    else
      let colorScheme = "evening"
    endif
    echo "setting color scheme to " . colorScheme
    execute "colorscheme " . colorScheme
endfunction
set statusline=%<%f\ %h%m%r%=%-20.(line=%l,col=%c%V,totlin=%L%)\%h%m%r%=%-40(,bytval=0x%B,%n%Y%)\ %{strftime(\"%c\")}%=0x%B\ %P
set statusline += \ %{SetTimeOfDayColors()}

The purpose of the last line is to have vim check the time whenever I make an edit and run the custom function. But I can't get it to work. Any suggestions? Thanks.

Answer 1

You need to remove the space immediately to the right of the +=.