Keystroke

A markdown parser and compiler written in TypeScript

Features

• Complete Markdown Parser: Supports headers, bold, italic, strikethrough, lists, blockquotes, links, and more
• Math Expressions: Parse mathematical notation with superscript (^) and subscript (~) support
• Checklists: Support for GitHub-style task lists with - [ ] and - [x]
• TypeScript: Fully typed codebase with comprehensive test coverage
• Modular Architecture: Separate lexer, parser, AST, and renderer components

Supported Markdown Elements

• Headers: # H1 through ###### H6
• Text Formatting: **bold**, *italic*, ~~strikethrough~~
• Lists:
  • Unordered: * item or - item
  • Checklists: - [ ] todo and - [x] done
• Blockquotes: > quoted text
• Links: [text](url)
• Code: `inline code`
• Math: $x^2 + y~1$ with superscript and subscript
• Horizontal Rules: ---

Usage

• Run tests with npm test
• Run with ts-node src/index.ts

Testing

The project includes comprehensive test coverage with 103 tests across all components:

• Token Tests: 56 tests covering lexical analysis
• AST Tests: 35 tests for abstract syntax tree nodes
• Lexer Tests: 10 tests for tokenization
• Renderer Tests: 15 tests for HTML output generation
• Interpreter Tests: 9 tests for end-to-end processing
• Parser Tests: 13 tests for syntax parsing

All tests are written in TypeScript and use Jest as the testing framework.

Architecture

The parser follows a traditional compiler architecture:

1. Lexer (src/Lexer.ts): Tokenizes markdown input
2. Parser (src/Parser.ts): Builds an Abstract Syntax Tree (AST)
3. AST (src/Ast.ts): Node types representing markdown elements
4. Renderer (src/Renderer.ts): Converts AST to HTML output

Development

# Install dependencies
npm install

# Run tests
npm test

# Run the parser
ts-node src/index.ts

# Compile TypeScript
npx tsc