kfl/wasm-experiments

Small WebAssembly snippet and some notes

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If you find anything confusing, misleading, out of date, or plain wrong.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.