Indentation rules in a VSCode plugin

Question

I'm writing a VSCode plugin to handle a certain scripting language.

This is the "language-configuration.json" file:

{
  "comments": {
    "lineComment": {
      "comment": "//",
      "noIndent": true
    }
  },
  "brackets": [
    ["(", ")"],
    ["[", "]"]
  ],
  "autoClosingPairs": [
    ["(", ")"],
    ["[", "]"],
    { "open": "'", "close": "'", "notIn": ["string", "comment"] },
    { "open": "\"", "close": "\"", "notIn": ["string"] },
    { "open": "`", "close": "`", "notIn": ["string", "comment"] }
  ],
  "surroundingPairs": [
    ["(", ")"],
    ["'", "'"],
    ["\"", "\""],
    ["[", "]"],
    ["%", "%"],
    ["<", ">"]
  ],
  "colorizedBracketPairs": [
    ["(", ")"],
    ["[", "]"]
  ],
  "autoCloseBefore": ";:.,=}])>` \n\t",
  "folding": {
    "markers": {
      "start": "^//section>.*$",
      "end": "^//endsection>.*$"
    }
  },
  "indentationRules": {
    "increaseIndentPattern": "^((?!\\/\\/).)*(\\([^)\"'`]*|\\[[^\\]\"'`]*)$",
    "decreaseIndentPattern": "^((?!\\/\\/).)*\\s*[\\)\\]].*$"
  },
  "onEnterRules": [
    {
      "beforeText": "^((?!\\/\\/).)*\\s*\\$[a-zA-Z0-9_]+\\([a-zA-Z0-9%_]+,",
      "action": { "indent": "indent" }
    },
    {
      "beforeText": "^((?!\\/\\/).)*\\s*.*,",
      "action": { "indent": "none" }
    },
    {
      "beforeText": "^\\/\\/$",
      "action": {
        "indent": "none"
      }
    },
    {
      "beforeText": "^\\/\\/\\s+.*$",
      "action": {
        "indent": "none",
        "appendText": "// "
      }
    }
  ]
}

The indentationRules and the onEnterRules are tested on the following code:

$trim()
$trim(%paster%,kalosh)

The lines of code are numbered from 1 to 2. I get the following results (in the following code, the | symbol indicates the cursor position)

line 1

-1- before pressing "enter"

$trim(|)

after pressing "enter"

$trim(
  |
)

This is the expected result.

-2- before pressing "enter"

$trim()|

after pressing "enter"

$trim()
|

This is the expected result.

line 2

-1- before pressing "enter"

$trim(|%paster%,kalosh)

after after pressing "enter"

$trim(
  |%paster%,kalosh)

This is the expected result.

-2- before pressing "enter"

$trim(%paster%,|kalosh)

after pressing "enter"

$trim(%paster%,
  |kalosh)

This is the expected result.

-3- before pressing "enter"

$trim(%paster%,kalosh|)

after pressing "enter"

$trim(%paster%,kalosh
  |)

NOT THE EXPECTED RESULT. The new line should have the same indentation as the previous one.

-4- before pressing "enter"

$trim(%paster%,kalosh)|

after pressing "enter"

$trim(%paster%,kalosh)
  |

NOT THE EXPECTED RESULT. The new line should have the same indentation as the previous one. I notice that in the first line of code, the same function but without parameters, the behavior is correct.

Question

How can I keep all the rules intact and also add the rule that says "if the cursor is at the end of a uncommented line, the next line should retain the indentation level of the current one"?

To try to solve the problem, I tried inserting the following as the first rule in onEnterRules:

{
  "beforeText": "^((?!\\/\\/).)*",
  "afterText": "\\s*$",
  "action": { "indent": "none" }
}

But not only did I not get the result I was looking for, but all the other rules were also not triggered.

Terr Lacont · Accepted Answer · 2025-10-02 08:53:46Z

1

Solved.

I submitted the problem to Copilot, Gemini, and Stack Overflow AI, and none of them were able to find the problem and fix it.

All I had to do was change the first two rules in onEnterRules to this:

...
{
  "beforeText": "^((?!\\/\\/).)*\\s*\\$[a-zA-Z0-9_]+\\([a-zA-Z0-9%_]+,$",
  "action": { "indent": "indent" }
},
{
  "beforeText": "^((?!\\/\\/).)*\\s*.*,$",
  "action": { "indent": "none" }
},
...

Basically, I added the end-of-line character $ to beforeText, and everything started working as expected again.

answered Oct 2 at 8:53

Terr Lacont

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