未知选项:\%{SetTimeOfDayColors()}

这是我的 .vimrc <<learning the vi and vim>> p201-203 .

function SetTimeOfDayColors()
    let currentHour = strftime("%H")
    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 += \ %{SetTimeOfDayColors()}

vim test.txt .

第15行:E518:未知选项:\%{SetTimeOfDayColors()}按ENTER键 或键入命令继续