javascript - 使字符串小写尊重引号 - Javascript

Question

我正在为 Domain Specific Language, 构建解析器(或 DSL，)我正在尝试将字符串转换为全部小写。我知道 toLowerCase 可以轻松完成此任务，但我需要保留用双引号或单引号(" 或 ')引起来的字符串在其原始情况下。例如，请参见以下内容:

输入:这是一个“串起你们”的测试，因为你们可以看到“你好，我的”

输出:这是一个测试“sTriNg Y'alL”，正如您所看到的“hEllO woRl\'o miNE'”

编辑:添加反斜杠引号

Answer 1

只是拼凑了一个快速解析器，不确定它的效果如何，但它应该处理无限制的反斜杠转义

function string_to_block(str) {
    var blocks = [],
        i, j, k;
    function isEscaped(str, i) {
        var escaped = false;
        while (str[--i] === '\\') escaped = !escaped;
        return escaped;
    }
    start: for (i = 0; i < str.length; i = j + 1) {
        find: for (j = i; j < str.length; ++j) {
            if (str[j] === '"' && !isEscaped(str, j)) {
                if (j > i) {
                    blocks.push({type: 'regular', str: str.slice(i, j)});
                }
                end: for (k = j + 1; k < str.length; ++k) {
                    if (str[k] === '"' && !isEscaped(str, k)) {
                        // found a "str" block
                        blocks.push({type: 'quote', str: str.slice(j, k + 1)});
                        j = k;
                        break find;
                    }
                }
                throw new SyntaxError('unclosed "str... starting at index ' + j);
            }
            if (str[j] === "'" && !isEscaped(str, j)) {
                if (j > i) {
                    blocks.push({type: 'regular', str: str.slice(i, j)});
                }
                end: for (k = j + 1; k < str.length; ++k) {
                    if (str[k] === "'" && !isEscaped(str, k)) {
                        // found a 'str' block
                        blocks.push({type: 'quote', str: str.slice(j, k + 1)});
                        j = k;
                        break find;
                    }
                }
                throw new SyntaxError("unclosed 'str... starting at index " + j);
            }
        }
    }
    if (k + 1 < str.length) {
        blocks.push({type: 'regular', str: str.slice(k + 1)});
    }
    return blocks;
}

现在

var foo = string_to_block("ThIs iS a teST \"sTriNg Y'alL\" aS yOu cAN sEE 'hEllO woRl\\' o miNE'");
/*
[
    {"type": "regular", "str": "ThIs iS a teST "},
    {"type": "quote"  , "str": "\"sTriNg Y'alL\""},
    {"type": "regular", "str": " aS yOu cAN sEE "},
    {"type": "quote"  , "str": "'hEllO woRl\\' o miNE'"}
]
*/

因此我们可以根据需要重新构建您的字符串；

var i, str = '';
for (i = 0; i < foo.length; ++i) {
    if (foo[i].type === 'regular') str += foo[i].str.toLowerCase();
    else str += foo[i].str;
}
str; // this is a test "sTriNg Y'alL" as you can see 'hEllO woRl\' o miNE'