Bash how to return value from subscript to main script?

Question

I have the following script saved into a menu.sh file.

declare -a menu=("Option 1" "Option 2" "Option 3" "Option 4" "Option 5" "Option 6")
cur=0

draw_menu() {
    for i in "${menu[@]}"; do
        if [[ ${menu[$cur]} == $i ]]; then
            tput setaf 2; echo " > $i"; tput sgr0
        else
            echo "   $i";
        fi
    done
}

clear_menu()  {
    for i in "${menu[@]}"; do tput cuu1; done
    tput ed
}

# Draw initial Menu
draw_menu
while read -sn1 key; do # 1 char (not delimiter), silent
    # Check for enter/space
    if [[ "$key" == "" ]]; then break; fi

    # catch multi-char special key sequences
    read -sn1 -t 0.001 k1; read -sn1 -t 0.001 k2; read -sn1 -t 0.001 k3
    key+=${k1}${k2}${k3}

    case "$key" in
        # cursor up, left: previous item
        i|j|$'\e[A'|$'\e0A'|$'\e[D'|$'\e0D') ((cur > 0)) && ((cur--));;
        # cursor down, right: next item
        k|l|$'\e[B'|$'\e0B'|$'\e[C'|$'\e0C') ((cur < ${#menu[@]}-1)) && ((cur++));;
        # home: first item
        $'\e[1~'|$'\e0H'|$'\e[H')  cur=0;;
        # end: last item
        $'\e[4~'|$'\e0F'|$'\e[F') ((cur=${#menu[@]}-1));;
         # q, carriage return: quit
        q|''|$'\e')echo "Aborted." && exit;;
    esac
    # Redraw menu
    clear_menu
    draw_menu
done

echo "Selected item $cur: ${menu[$cur]}";

I now have a second main.sh where i call the menu.sh file like this: ./menu.sh (they are in the same directory). How can i get the output of the menu.sh from the main.sh? I can't get the echo to the standard output by piping or redirecting for some reason. Accessing it via $() also doesn't work. What am i doing wrong?

Thanks in advance for all helpt!