Microsoft/monaco-editor

[Bug] language:markdown italic error

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#4224 opened on Oct 26, 2023

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buggrammarshelp wanted

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 Link

image

Monaco Editor Playground Code

Language:markdown

_italic_
$a_{1}$:expect normal but italic$b_{1}$
$a_{1}$:normal$b$
*italic*

Reproduction Steps

No response

Actual (Problematic) Behavior

No response

Expected Behavior

No response

Additional Context

No response

Contributor guide

Tech stack
typescript
Domain
frontend
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
mostly clear
Prerequisites
Knowledge of TextMate grammarsFamiliarity with monaco editor's tokenizer
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
50
Research direction
The issue is that underscores inside math formulas ($...$) are incorrectly rendered as italic in markdown. The fix likely involves modifying the markdown language grammar (e.g., markdown.tmLanguage.json or monarch tokenizer rules) to disable italic inside math environments. Look at the existing grammar files in src/language/markdown/, particularly the tokenizer rules for ` ` and `*`. Investigate how math formulas are tokenized and ensure that underscores inside $...$ are not treated as emphasis markers. Test with the provided example after making changes.