Main (){
    if [ ! -z $A ];then
        RES="${A}"
    fi
    if [ ! -z $B ];then
        RES+=":${B}"
    fi
    if [ ! -z $C ];then
        RES+="\\${C}"
    fi
    if [ ! -z $D ];then
        RES+="//${D}"
    fi

    echo $RES

}



while test -n "$1"; do
    case "$1" in

        --protocol | -p)
            PROTOCOL=$2
            shift ;;

        --a )
            A=$2
            shift;;

        --b )
            B=$2
            shift;;

        --c )
            C=$2
            shift;;

        --d )
            D=$2
            shift;;

        *)
            echo "Unknown argument: $1"
            exit $STATE_UNK ;;
        esac
    shift
done

Main