PLDB - A Programming Language Database

PLDB is a comprehensive public domain database containing over 135,000 facts about more than 5,000 programming languages. The project includes both the complete dataset and the website code for pldb.info.

🌟 Key Features

• Rich Dataset: Extensive information about programming languages, from high-level formats to binary specifications
• Multiple Export Formats: Access the complete dataset in CSV, TSV, or JSON format
• Public Domain: All data and code is freely available for any use
• Regular Updates: Actively maintained with version control and release notes
• Web Interface: Browse the data through an intuitive web interface at pldb.info

📊 Data Downloads

Access the complete dataset in your preferred format:

• CSV: pldb.info/pldb.csv
• TSV: pldb.info/pldb.tsv
• JSON: pldb.info/pldb.json

Full documentation for the data formats is available at pldb.info/csv.html

🚀 Local Development

Quick Start (Build & Serve)

# Clone the repository
git clone https://github.com/kaby76/pldb
cd pldb

# Install dependencies
npm install

# Build everything and start local server
npm run build:serve

Then open http://localhost:3000 in your browser.

Prerequisites

• Node.js (v18 or later recommended)
• npm
• cloc (optional, for line counting): npm i -g cloc

NPM Scripts

Command	Description
npm run build	Build the entire site
npm run build:serve	Build and start local server
npm run serve	Start local server (without rebuilding)
npm run test	Run tests
npm run format	Format code before committing

What the Build Does

The build script (build.js) performs these steps in order:

1. Build parsers - Compiles the parser definitions
2. Patch scroll-cli - Automatically patches scroll-cli for Windows compatibility (if needed)
3. Build root folder - Generates pldb.json, measures.json, and root HTML files
4. Generate feature pages - Creates .scroll files for each language feature
5. Build subfolders - Builds all content folders in the correct order:
   • blog/, books/, concepts/, creators/, features/, lists/, pages/

Build order matters: creators/ must be built before lists/ (lists needs creators.json)

Manual Build Steps

If you need to run build steps manually:

# 1. Build the parsers file
node cli.js buildParsersFile

# 2. Build the root folder
node ./node_modules/scroll-cli/scroll.js build

# 3. Generate feature pages (requires measures.json from step 2)
node -e "const {Tables} = require('./Computer.js'); Tables.writeAllFeaturePages()"

# 4. Build all subfolders
for dir in blog books concepts creators features lists pages; do
  (cd "$dir" && node ../node_modules/scroll-cli/scroll.js build)
done

# 5. Start server
npx serve .

Troubleshooting

Windows/MSYS2 users: The build script automatically patches scroll-cli for Windows path compatibility. If you encounter path-related errors, the patch replaces Utils.posix.dirname/basename with require("path").dirname/basename in node_modules/scroll-cli/parsers/root.parsers.

Empty tables or missing data: Ensure all subfolders are built. The npm run build command builds everything, but if you're building manually, remember that creators/ must be built before lists/.

Port already in use: If port 3000 is busy, use npx serve . -l 8080 to use a different port.

📁 Repository Structure

The most important components of the repository:

• concepts/: Contains the ScrollSet (individual files for each concept)
• code/measures.parsers: Contains the Parsers (schema) for the ScrollSet
• View detailed language statistics at pldb.info/pages/about.html

🏆 Rankings

PLDB includes a sophisticated ranking system for programming languages based on five key metrics:

• Number of estimated users
• Foundation score (languages built using this language)
• Estimated job opportunities
• Language influence
• Available measurements

Learn more about the ranking algorithm at pldb.info/pages/the-rankings-algorithm.html

📜 Version History

Latest major releases:

• 9.0.0 (May 2024): Migrated to Scroll 84
• 8.0.0 (March 2023): Upgraded to TrueBase 9
• See Release Notes for complete history

🤝 Contributing

Contributions are welcome! PLDB is designed for two main audiences:

1. Programming Language Creators: Use our organized data to make informed design decisions
2. Programming Language Users: Get data-driven insights about the programming language ecosystem

📚 Resources

• Main Website: pldb.info
• About Page: pldb.ifno/pages/about.html
• Acknowledgements: pldb.info/pages/acknowledgements.html

📖 Citation

This project is dedicated to the public domain. When using PLDB, we appreciate attribution but it's not required. All sources are listed at pldb.info/pages/acknowledgements.html.

🚢 Making Changes and Deploying

1. Make your changes locally

Edit the ScrollSet files in concepts/, update parsers in code/measures.parsers, or modify any other source files.

2. Push to main

When you push to the main branch, a GitHub Actions workflow automatically:

• Installs dependencies and builds the site
• Packages the built site into site.tar.gz
• Publishes it as a GitHub Release tagged latest

The build takes about 2 minutes on GitHub's runners.

3. Deploy to server

The setup-pldb.sh script deploys the pre-built site to a fresh Ubuntu server (tested on Ubuntu 24.04). It downloads the build artifact from GitHub Releases, so no building happens on the server.

Requirements:

• A fresh Ubuntu server with SSH access as root
• SSH key authentication configured
• A successful GitHub Actions build (the latest release must exist)

./setup-pldb.sh <ip-address> <repo-url>
# Example:
./setup-pldb.sh 159.65.99.188 https://github.com/kaby76/pldb.git

The script will:

• Install Node.js 20.x
• Show a maintenance page while deploying
• Download the pre-built site from GitHub Releases
• Configure a systemd service (pldb) to serve the site on port 80
• Start the server automatically on boot

Managing the server

systemctl status pldb    # Check status
systemctl restart pldb   # Restart server
systemctl stop pldb      # Stop server
journalctl -u pldb -f    # View logs

Redeploying after changes

After pushing new changes to main, wait for the GitHub Actions build to complete, then re-run setup-pldb.sh to deploy the updated site.

🌐 Mirrors

The primary site is hosted at pldb.info via ScrollHub. For offline access or redundancy, you can clone the repository and build locally:

git clone https://github.com/kaby76/pldb.git
cd pldb
git pull  # To keep updated