Markdown Parser

A comprehensive Markdown to HTML converter built in Rust using Pest grammar. This project provides a command-line interface and library for parsing Markdown documents.

Installation

From crates.io

cargo install arinamcnulty-markdown-parser

From Source

git clone https://github.com/arinamcnulty/markdown-parser.git

cd markdown-parser

cargo build --release

Usage

Command Line Interface

Convert a Markdown file to HTML

markdown_parser convert -i document.md -o document.html

Parse Markdown text directly

markdown_parser parse -t "# Hello World!"

Display help and credits

markdown_parser info

Library Usage

use markdown_parser::{str_to_html, convert_file_to_html};

fn main() -> Result<(), Box<dyn std::error::Error>> {
    // Parse markdown string
    let markdown = "# Hello World\n\nThis is **bold** text with `inline code`.";
    let html = str_to_html(markdown)?;
    println!("{}", html.join("\n"));

    // Convert file
    convert_file_to_html("input.md", "output.html")?;

    Ok(())
}

Grammar Examples

This parser supports the full CommonMark Markdown specification. Here are examples of supported syntax:

Headings

# Heading Level 1

## Heading Level 2

### Heading Level 3

Text Formatting

**Bold text**
*Italic text*
~~Strikethrough text~~
__Underline text__

Links and Images

[Click here](https://example.com)
![Alt text](image.png)

Inline Code

Use `code` for inline code snippets.

Code Blocks

```rust
fn main() {
    println!("Hello, world!");
}
```

Lists

Unordered Lists

- Item 1
- Item 2
* Another item

Ordered Lists

1. First item
2. Second item
3. Third item

Blockquotes

> This is a blockquote
> Second line of blockquote

Horizontal Rules

---
***
___

Escaped Characters

\*literal asterisk\*
\[literal bracket\]

Grammar Structure

The parser uses Pest grammar for efficient parsing. The grammar is organized into the following main components:

Document Structure

document_structure = { SOI ~ (document_block ~ NEWLINE*)* ~ document_block? ~ EOI? }
document_block = {
    document_heading
  | document_quote
  | code_fence
  | document_unordered_list
  | document_ordered_list
  | thematic_break
  | document_paragraph
}

Inline Content

inline_content = _{
    image
  | link
  | text_formatting
  | inline_code
  | escape_sequence
  | plain_text
}

Text Formatting

text_formatting = _{
    bold_formatting
  | italic_formatting
  | strikethrough_formatting
  | underline_formatting
}

Testing

Run the test suite:

cargo test

Run with formatting and linting:

cargo fmt

cargo clippy

API Documentation

Core Functions

• parse_markdown(input: &str) - Parse markdown string to syntax tree
• str_to_html(input: &str) - Convert markdown string to HTML vector
• convert_file_to_html(input: &Path, output: &Path) - Convert markdown file to HTML file
• print_html_to_console(input: &str) - Print HTML conversion to stdout

Error Types

#[derive(Debug, thiserror::Error)]
pub enum MarkdownError {
    #[error("Parsing failed: {0}")]
    ParseError(String),

    #[error("File operation failed: {0}")]
    IoError(#[from] std::io::Error),
}

Development

Project Structure

src/
├── main.rs          # CLI application
├── lib.rs           # Library implementation
└── grammar.pest     # Pest grammar rules

tests/
└── grammar_tests.rs # Unit tests

Adding New Grammar Rules

1. Add rule to grammar.pest
2. Implement conversion function in lib.rs
3. Add rule to convert_to_html match statement
4. Add unit tests in tests/grammar_tests.rs

Building for Development

cargo build

cargo run -- info

Code Quality

• Formatting: cargo fmt
• Linting: cargo clippy
• Testing: cargo test

Author

Zudilova Oryna - Initial work - arinamcnulty