如何合并VS Code代码片段实现替换不同前导空格为星号

问题 #

我有两个VS Code代码片段，分别能把非空行的前导4个空格替换为*、前导8个空格替换为**。现在想把它们合并成一个代码片段，实现：行首有4个空格就替换为单个*，有8个空格就替换为双**，示例输入输出如下，该怎么实现？

现有代码片段 #

"Replace leading 4 spaces of non-empty lines with *": {
    "body": [
      "${TM_SELECTED_TEXT/^([ ]{4})(.+)$/* $2/gm}"
    ],
    "description": "Replace leading 4 spaces of non-empty lines with *"
  },
  "Replace leading 8 spaces of non-empty lines with **": {
    "body": [
      "${TM_SELECTED_TEXT/^([ ]{8})(.+)$/** $2/gm}"
    ],
    "description": "Replace leading 8 spaces of non-empty lines with **"
  },

示例输入 #

Motivation's First Law (Law of Persistence):
    A person will remain in their current state of motivation
    In simpler terms, individuals tend to maintain their current

Motivation's Second Law (Law of Momentum):
    The rate of change of motivation of a person is 
    In simpler terms, this law suggests that the greater 

示例输出 #

* Motivation's First Law (Law of Persistence):
** A person will remain in their current state of motivation
** In simpler terms, individuals tend to maintain their current

* Motivation's Second Law (Law of Momentum):
** The rate of change of motivation of a person is
** In simpler terms, this law suggests that the greater

解决方案 #

可以利用VS Code代码片段的正则分支匹配和条件替换，实现一次处理两种前导空格的需求，合并后的代码片段如下：

"Replace leading 4/8 spaces with * or **": {
  "body": [
    "${TM_SELECTED_TEXT/^([ ]{8})(.+)$|^([ ]{4})(.+)$/${1:+** }${2:+$2}${3:+* }${4:+$4}/gm}"
  ],
  "description": "Replace leading 8 spaces with **, leading 4 spaces with * for non-empty lines"
}

逻辑说明 #

• 正则规则^([ ]{8})(.+)$|^([ ]{4})(.+)$：用|划分两个匹配分支，优先匹配8个空格的行（避免4空格规则提前匹配掉8空格的前4个字符），再匹配4个空格的行，两个分支分别捕获空格和后续内容。
• 替换规则${1:+** }${2:+$2}${3:+* }${4:+$4}：
  • ${1:+** }：如果第一个分组（8个空格）匹配成功，替换为**
  • ${2:+$2}：保留8个空格后的文本内容
  • ${3:+* }：如果第三个分组（4个空格）匹配成功，替换为*
  • ${4:+$4}：保留4个空格后的文本内容

这样就能在一次替换中同时处理两种场景，达到预期效果。

内容的提问来源于stack exchange，提问作者Ahmad Ismail