Toolchain

mix_gale manages the Gale compiler for your Mix project. Start with the Quick Start to add Gale to a project; use this page to check platform requirements or configure a compiler.

Supported platforms

Gale targets Elixir 1.20 on OTP 28 or newer. Prebuilt compilers support:

Platform	Requirements
Linux x86_64	glibc 2.39 or newer, such as Ubuntu 24.04
macOS arm64	Apple Silicon

Prebuilt compilers are not yet available for Linux arm64, Intel macOS, musl, or Windows.

Compiler versions

mix_gale and the compiler share a version. When you run mix compile, mix_gale downloads the compiler with its exact Mix project version and verifies the download against its SHA-256 checksum. It reuses the installed compiler on subsequent builds.

To upgrade the toolchain, update the Git ref in mix.exs or run mix deps.update mix_gale gale_std when tracking main, then commit the updated mix.lock. The next compilation uses the compiler version declared by the selected mix_gale commit.

Each Gale release also declares one exact proof toolchain. Gale 0.1.0 supports Why3 1.8.2 and Z3 4.16.0. Run gale version for the human-readable contract or gale version --json for tooling. Compiler-library users can read Gale.proof_toolchain. gale verify checks both tools before proving and reports an error for any other version; Gale libraries do not select solver versions or contain compatibility branches.

The repository’s locked Nix development shell installs the supported pair and asserts their versions. Users who manage packages another way install the exact versions reported by their Gale executable. A future solver upgrade is a Gale release change: update the Nix lock/package assertions, the release metadata, and the proof regression suite together.

Find the compiler

Run this from your project to print the compiler’s executable path:

mix gale.path

The command downloads the matching compiler if needed. Use the resulting path when configuring an editor or another tool that needs the compiler executable.

Use a local compiler

To use a compiler you built yourself, add compiler_path to the gale configuration in your mix.exs project settings:

gale: [compiler_path: "/absolute/path/to/gale"]

This setting takes precedence over the managed compiler and skips its download. Keep the local compiler compatible with your project’s mix_gale version.

Mix does not search PATH or read a compiler-path environment variable automatically. To configure the path through your environment, set it explicitly:

gale: [compiler_path: System.get_env("GALE_COMPILER_PATH")]

When the variable is unset, Mix uses the managed compiler.