Arrays 通过proc传递字符串数组

这是我在MEL中的代码，但我不知道为什么它没有运行：

window -width 150;
columnLayout -adjustableColumn true;
    button -label "Button 1" -command "Base";
    button -label "Button 2" -command "Top";
    button -label "Button 3" -command "test";
showWindow;

global string $BaseCurves, $TopCurves;

global proc Base () {
    $BaseCurves=`ls -sl`;
}

global proc Top () {
    $TopCurves=`ls -sl`;
}

global proc test () {
    print $TopCurves[0];
}

我不知道我为什么会有这个错误：

"$TopCurves" is an undeclared variable.

---

请尝试以下代码：

global string $BaseCurves;

window -width 150;
columnLayout -adjustableColumn true;
    button -label "Button 1" -command "Base";
    button -label "Button 2" -command "Top";
    button -label "Button 3" -command "test";
showWindow;

global proc Base() {
    $BaseCurves=`ls -sl`;
};

global proc Top() {
    $TopCurves=`ls -sl`;
};

global proc test() {
    string $TopCurves[0];
};

---

请尝试以下代码：

global string $BaseCurves;

window -width 150;
columnLayout -adjustableColumn true;
    button -label "Button 1" -command "Base";
    button -label "Button 2" -command "Top";
    button -label "Button 3" -command "test";
showWindow;

global proc Base() {
    $BaseCurves=`ls -sl`;
};

global proc Top() {
    $TopCurves=`ls -sl`;
};

global proc test() {
    string $TopCurves[0];
};