javascript - 修改字符串中的 for 循环

Question

我有字符串，它包含一些代码。我想对它做一些改变。我想用js修改一个for循环。循环:

"for i in 0..10 loop"

我希望它是:

"for (var i=0; i<10; i++)"

听起来我很复杂。最简单的方法应该是什么？

Answer 1

根据我的评论，这里是简单的实现:

var before = "for i in 0..10 loop";
var after = Translate(before);

function Translate(command) {
    var tokens = command.split(" ");
    if (tokens.length != 5)
        return "ERROR: invalid command (wrong number of tokens)";
    if (tokens[0] != "for" || tokens[2] != "in" || tokens[4] != "loop")
        return "ERROR: invalid command (syntax error)";
    var indices = tokens[3].split("..");
    if (indices.length != 2)
        return "ERROR: invalid command (invalid indices format)";
    var startIndex = parseInt(indices[0], 10);
    var endIndex = parseInt(indices[1], 10);
    if (isNaN(startIndex) || isNaN(endIndex))
        return "ERROR: invalid command (illegal indices)";
    var varName = tokens[1];
    return "for (var " + varName + "=" + startIndex + "; " + varName + "<" + endIndex + "; " + varName + "++)";
}

Live test case .

它并不完美，例如您可以进一步检查变量名称是否合法，即以英文字母开头，而不是保留字等。