WAET: The WebAssembly Edn Toolkit

WAET (prounced "weight") is the Clojure-equivilent of WABT, the WebAssembly Binary Toolkit.

The WebAssembly Edn Toolkit provides a collection of Babashka scripts in the style of WABT's C++ programs for manipulating various WebAssembly file formats.

Provided Tools:

• wat2wie -- Converts WebAssembly Text into WebAssembly In Edn.
• wie2wasm -- Converts WebAssembly In Edn to binary WebAssembly. Accepts the same options as wat2wasm.
• wat2wie2wasm -- Behaves as wat2wasm, but detours through WIE for testing purposes.

Additionally -- and perhaps most importantly -- WAET provides the above functionality as a Clojure library for the purpose of being a pleasant compilation toolkit for compilers targeting WebAssembly.

Status

Feature incomplete, barely tested, incompletely documented, and completely unstable. The Waet syntax and command line tools are alpha status. The Clojure API is expected to undergo significant breaking changes.

Primarily tested in terms of a subset of wabt's own test suite.

WIE: WebAssembly In Edn

WAT (WebAssembly Text) is already an sexpression language and so has a great deal of common syntax with EDN (Clojure's Extensible Data Notation).

Where possible, WAT syntax is used directly. Where not possible, WAT is translated to WAET as described here.

Strings and Data

Clojure on the JVM uses UTF-16 strings, but WAT data strings specify UTF-8 data. This means that binary data can not safely be encoded into strings. Instead, strings are treated abstractly and encoded into UTF-8 when written into Wasm binary. To exactly encode binary data, use #waet/data[ ... ] tagged literals. Each element of the vector is a data "chunk" which may be a string or number. Big integers are encoded big-endian, other integers are treated as individual bytes.

Attributes

WAT attributes are encoded with the #waet/attribute(NAME & DATA...) tagged literal.

Other Differences

• TODO: Document more differences.

Usage

See waet.core. There will be two modes: Compile an entire module, or compile modulefield-by-modulefield.

Testing

Use ./test.sh, which delegates to $WABT_HOME/run-tests.sh and injects Waet's toolchain.

License

Copyright © 2024 Brandon Bloom

Distributed under the Eclipse Public License 1.0.