Polylang.io

Polylang.io provides free, open-source code playgrounds in 10 programming languages. No account is required, and all playgrounds are shareable. We currently support Python 3.4, Python 3.10 with scientific libraries, Julia, Golang, Ruby, C, C++, Perl, OCaml, and PHP. Check it out at polylang.io!

The Magic of WebAssembly

What makes Polylang different from other online code playgrounds is that it runs entirely in your browser - the compiler for the language you are using is a mixture of Javascript and WebAssembly running locally on your computer. There is no server running your code, just your computer and your browser!

Deploying and Developing

The frontend is a static Svelte website and the backend is a Python API using the Chalice framework (check the folder /api for more information). The website is designed to be deployed statically using AWS Lambda Python serverless functions with a serverless AWS DynamoDB database. However, any static hosting platform and serverless platform would also work as long as the database logic and config files are slightly tweaked.

To develop on the frontend, install the npm dependencies then run npm run dev. Check /api/README.md for more information about running the backend.

Inside the /wasm folder are static assets including most of the .wasm files that contain the compilers and interpreters needed to run the various languages on Polylang. These are published as public NPM packages to take advantage of the free JSDelivr CDN.

Todo

• Use a smaller C compiler. Currently, the Clang/C/C++ wasm files sum to about 50 mb. This takes a long time to load and is more expensive to serve. There are small C compilers that are around 1 mb or less that would be a better fit for Polylang. TCC implements C99 and 8cc implements C11. C11 is preferred, but both would be nice to have.
• Matrix operations in Julia are broken.
• Certain languages are large. Julia, C++, Golang, and OCaml are roughly 50 mb. I'm open to proposals on the best ways to shrink these.
• Golang is around 50 mb - this could be brought down by compiling TinyGo to WebAssembly.
• Implement Rust, R, Objective-C, Kotlin, Java, C-Sharp, Haskell, etc. If the compiled package size is over 50 mbs when compressed, the download speed will be slow and the speed of the WASM binary in the browser will likely also be slow. So please, only work on one of these languages if you think you can get the final WASM package to be less than 50 mbs compressed.

Inspirations, Acknoledgements, and OSS Projects Used by Polylang

• micropython's javascript port for Python 3.4.
• pyodide for Python 3.8 with scientific libraries.
• julia-wasm for Julia to WebAssembly compilation.
• wasm-go-playground for Golang to WebAssembly compilation.
• mruby for a lightweight version of Ruby.
• wasm-clang for C/C++ to WebAssembly compilation.
• webperl for Perl to WebAssembly compilation.
• js-of-OCaml for compiling the OCaml toplevel to Javascript.
• pib for PHP.
• Related and interesting work: see compile-to-web for languages with LLVM support and Wasm support.

License

Polylang is free for anyone to use at polylang.io.

The license for Polylang's codebase is the GPLv3 license. Additionally, each language offered by Polylang is typically licensed with the same license that the language's compiler or interpreter uses. I would have loved to do the MIT license but some of the Polylang languages use a GPL license, so it made sense to chose something compatible.