Zaozi is an experimental project aimed at rewriting Chisel in pure Scala 3. It will not replace Chisel, but provide a minimized solution to create an plugable eDSL in Scala 3. The goal of this project is providing an eDSL frontend framework for hardware designs.

Zaozi compiles with --release 25 (classfile major version 69), so JDK 25 is the minimum runtime and the only supported development JDK. The supported setup path is nix develop against this repository's flake.nix, which provisions JDK 25 (nixpkgs.jdk25), Mill 1.1.2 (with mill.jre = jdk25), Scala 3.7.4, scala-cli 1.12.1, jextract (May 2025 source, built on JDK 25), MLIR / CIRCT, lit, and z3.

• mlirlib: A Java module that maintains all MLIR C-API definitions. It can be a generic layer for any MLIR infrastructure in Scala 3.

• circtlib: A Java module that maintains all CIRCT C-API definitions, currently mainly for Firrtl. Developers adding new dialects to Zaozi should expose them in CIRCT and include them here.

• zaozi: The core DSL implementation, encompassing the type system and build entries. It focuses on module-level construction, allowing modules to implement specific interfaces without extending from a base class.

Zaozi emphasizes a modular and minimalistic approach, delegating build processes to MLIR via C-API.

This strategy reduces JVM memory usage by avoiding local AST storage and eliminates serialization overhead by directly binding MLIR values to Scala values via the MLIR C-API.

Additionally, Zaozi separates the eDSL API declaration with Scala 3 given pattern, supporting swap APIs implementation through given a type class.

The project is licensed under the Apache License 2.0.

© Jiuyang Liu liu@jiuyang.me. All Rights Reserved.