microsoft / microsoft/monaco-editor

[Bug] C++ Raw strings aren't properly handled when the delimiter contains a quote

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bug grammars help wanted languages-basic
Dominant language
JavaScript
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Description

Reproducible in vscode.dev or in VS Code Desktop?
  • Not reproducible in vscode.dev or VS Code Desktop
Reproducible in the monaco editor playground?
Monaco Editor Playground Code
monaco.editor.create(document.getElementById('container'), {
	value: `
int main() {
    auto _ = R""( content )"";
}`,
	language: 'cpp'
});
Reproduction Steps

paste the code in the js section and observe the resulting highlight being wrong

Actual (Problematic) Behavior

The raw string end isn't properly detected and the string highlighting continues until the end of the file

Expected Behavior

the raw string's end is properly detected

Additional Context

C++ raw string have the form R"delimiter(content)delimiter" where the delimiter is a (possibly empty) sequence of characters that may include quotes. when the delimiter contains quotes, the end isn't properly detected. having looked at the sources, while I don't understand everything, it looks a lot like this regex is responsible, as it exclude the quotes from the characters making up the delimiter (there's a mismatch with the regex for the opening delimiter):

raw: [
  [
    /(.*)(\))(?:([^ ()\\\t"]*))(\")/,

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start with src/basic-languages/cpp/cpp.ts, especially the raw-string rule linked in the report, and reproduce the highlighting in the Monaco Editor Playground using the supplied TypeScript snippet. Compare the opening and closing delimiter patterns; done means the closing delimiter is detected when it contains quotes and highlighting stops at the raw string’s end.

Written by the indexing model from the issue text.

Assessment

Tech stack
cpp, typescript
Domain
tooling
Issue type
Bug
Difficulty
2/5
Estimated time
1-3 hours
Activity status
Stale
Clarity
Clearly specified
Newbie friendliness
58/100

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