switch vim color scheme to match iterm profile

.vimrc

" If we're using iterm2 (OS X), check if there's a colorscheme in vim matching the iterm2 profile name.
" If the profile name has suffix " - light" then set bg=light else bg=dark.
" If we're not using iterm2, based on the time of day, pick a colorscheme light (day) vs dark (night).
" I like the yin and yang colorschemes for vim and iterm2: https://github.com/pgdouyon/yin-yang
" So I have a profile in iterm2 named "yang - light" and "yin - dark".
" Note: iterm2 does not _update_ the env var ITERM_PROFILE after _changing_ the profile, just on launch.
" You'll have to `source ~/.vimrc` after changing the iterm2 profile or if not running vim, launch it.

let itermprofile = system("osascript -e 'tell application \"iTerm2\"\nget profile name of current session of current window\nend tell'")
try
  if itermprofile =~ " - light"
    execute "colorscheme " . substitute(itermprofile, " - light", "", "")
    set background=light
  elseif itermprofile =~ " - dark"
    execute "colorscheme " . substitute(itermprofile, " - dark", "", "")
    set background=dark
  else
    " no "- light" nor "- dark" so try verbatim.
    execute "colorscheme " . itermprofile
    set background=dark    " assume it is dark
  endif
catch /^Vim\%((\a\+)\)\=:E185/
  " Not using iterm2 or colorscheme not found.
  let hr = system('date +%H')
  if hr < 8 || hr > 17
    " early morning or late at night
    set background=dark
    color yin
  else
    " daytime
    set background=light
    color yang
  endif
endtry