WebAssembly Experimental Code

This repository contains some short guides and small snippets of WebAssembly (WASM) and code interacting with WASM.

The repository started out as a various examples, gists and guides that I have made either for students or for understanding a specific aspect of WASM or how to use some tool.

If you find anything confusing, misleading, out of date, or plain wrong. Please open an issue or make a PR.

The code and guides are currently focused on writing WASM by hand in the textual format, aka WAT.

Tools and resources

The following list is incomplete. I mostly use the following tools:

• The official WebAssembly webpage

• The reference interpreter is a fantastic Swiss Army knife for working with WASM. It understands both the textual and binary format of WASM and can translate between formats, it has an interactive interpreter, and a scripting language (WAST) that can be used for testing WASM modules.

• WABT is a suite of standalone cli tools for WASM. Easy to install on most platforms.

• Binaryen both a suite of cli tools, and a compiler and toolchain infrastructure library.

Converting between the textual format and the binary format

The reference interpreter can translate WAT to WASM:

$ wasm fact.wat -o fact.wasm

or from WASM to WAT ( be careful you don't overwrite your files ), which can be useful if you want to inspect some WASM created by an other tool or compiler:

$ wasm fact.wasm -o fact.wat

Or you can use wat2wasm and wasm2wat from WABT:

$ wat2wasm fact.wat
$ wasm2wat fact.wasm

The guides

The repository currently contains the following guides:

• Testing with the reference interpreter
• Optimising with Binaryen

Files referred to in the guides are in the code directory, plus a few more examples that I haven't gotten around writing guides for yet.