go - 实例化结构和数组不会创建新的引用

Question

我正在尝试将一个简单的 markdown 文件转换为 json，markdown 看起来像这样:

#TITLE 1
- Line 1
- Line 2
- Line 3

#TITLE 2
- Line 1
- Line 2
- Line 3
<!-- blank line -->

我无法理解在 func main() 中重构以下内容需要什么:

    type Section struct {
        Category string
        Lines    []string
    }

    file, _ := os.Open("./src/basicmarkdown/basicmarkdown.md")

    defer file.Close()

    rgxRoot, _ := regexp.Compile("^#[^#]")
    rgxBehaviour, _ := regexp.Compile("^-[ ]?.*")

    scanner := bufio.NewScanner(file)

    ruleArr := []*Section{}
    rule := &Section{}

    for scanner.Scan() {

        linetext := scanner.Text()

        // If it's a blank line
        if rgxRoot.MatchString(linetext) {
            rule := &Section{}
            rule.Category = linetext
        }

        if rgxBehaviour.MatchString(linetext) {
            rule.Lines = append(rule.Lines, linetext)
        }

        if len(strings.TrimSpace(linetext)) == 0 {
            ruleArr = append(ruleArr, rule)
        }

    }

    jsonSection, _ := json.MarshalIndent(ruleArr, "", "\t")
    fmt.Println(string(jsonSection))

上面的代码输出:

[
{
        "Category": "",
        "Lines": [
            "- Line 1",
            "- Line 2",
            "- Line 3",
            "- Line 1",
            "- Line 2",
            "- Line 3"
        ]
    },
    {
        "Category": "",
        "Lines": [
            "- Line 1",
            "- Line 2",
            "- Line 3",
            "- Line 1",
            "- Line 2",
            "- Line 3"
        ]
    }
]

当我希望输出:

[
    {
        "Category": "#TITLE 1",
        "Lines": [
            "- Line 1",
            "- Line 2",
            "- Line 3"
        ]
    },
    {
        "Category": "#TITLE 2",
        "Lines": [,
            "- Line 1",
            "- Line 2",
            "- Line 3"
        ]
    }
]

肯定有几处错误。请原谅这个问题的冗长，当你是菜鸟时，没有例子很难解释。提前致谢。

Answer 1

在 for 循环中，仔细看看这部分:

// If it's a blank line
if rgxRoot.MatchString(linetext) {
    rule := &Section{} // Notice the `:=`
    rule.Category = linetext
}

您基本上是在 if 的范围内创建一个新的 rule 变量，而您可能想重用您已经在 之外创建的变量for 循环。

因此，尝试将其更改为:

// If it's a blank line
if rgxRoot.MatchString(linetext) {
    rule = &Section{} // Notice the `=`
    rule.Category = linetext
}