PLDB Readme

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PLDB is a public domain ScrollSet and website containing over 135,000 facts about over 5,000 programming languages.

This repo contains the entire ScrollSet, code, and website for http://pldb.info.

To download the data

The entire ScrollSet is ready to analyze in popular formats. Full documentation is here: http://pldb.info/csv.html

To build the site locally

git clone https://github.com/breck7/pldb
cd pldb
# Required to run this during first install only.
npm i -g cloc
# Required to run this on fresh checkout and when upgrading from an old checkout or periodically when there are new releases
npm install .
# (Optional) Run tests
npm run test
npm run build
# After you make changes and before you commit make sure to run:
npm run format

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

After deployment, manage the server with:

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.

To explore this repo

The most important folder is concepts, which contains the ScrollSet (a file for each concept). The file code/measures.parsers contains the Parsers (schema) for the ScrollSet.

You can see the cloc language stats on this repo at http://pldb.info/pages/about.html.

Citation

PLDB content is published to the public domain and you can use it freely. If needed, here are 3 options for citing PLDB:

http://pldb.info

PLDB contributors. (2026) - "PLDB: a Programming Language Database". Retrieved from: 'http://pldb.info' [Online Resource]

@article{pldb,
  author = {PLDB contributors},
  title = {PLDB: a Programming Language Database},
  journal = {PLDB},
  year = {2026},
  note = {http://pldb.info}
 }

All sources for PLDB can be found here: http://pldb.info/pages/acknowledgements.html