#defcomp -condition-

local prev="$words[CURRENT-1]"

if [[ "$prev" = -o ]]; then
  compgen -o -M 'L:|[nN][oO]= M:_= M:{A-Z}={a-z}'
elif [[ "$prev" = -([no]t|ef) ]]; then
  _files
else
  _files
  compgen -v
fi