#defcomp unsetopt

local nm=$compstate[nmatches]

compgen -M 'L:|[nN][oO]= M:_= M:{A-Z}={a-z}' \
         -s '$({ unsetopt kshoptionprint; setopt } 2>/dev/null)'
[[ compstate[nmatches] -eq nm ]] &&
    compgen -M 'L:|[nN][oO]= M:_= M:{A-Z}={a-z}' -o