SubsetJuliaVM

SubsetJuliaVM is a Rust implementation that runs a static subset of Julia without a JIT. It parses Julia source with a pure Rust parser and executes it through a pipeline of lowering → Core IR → bytecode compiler → stack VM.

It also provides a C ABI for iOS and WebAssembly bindings for the web.

To use sjulia, you need to embed caches into the binary. It works without caches, but cold start is very slow, so caches are practically required.

$ ./scripts/sjulia_install.sh   # Windows: pwsh -File scripts/sjulia_install.ps1
$sjulia examples/mandelbrot.jl
  0.027875 seconds
Mandelbrot Set (50x25):

                              .
                              . .
                              .+
                             ###+.
                        .   .####.
                       .#++#########....
                      ..##############.
            .        ..################..
             ...... .##################.
            .#######.###################
          ...##########################.
#####################################..
          ...##########################.
            .#######.###################
             ...... .##################.
            .        ..################..
                      ..##############.
                       .#++#########....
                        .   .####.
                             ###+.
                              .+
                              . .
                              .

To compile examples/mandelbrot.jl ahead of time into a native binary, build juliars with the AoT feature and use the minimal AoT prelude:

$ cargo build --release -p subset_julia_vm --features aot --bin juliars
$ target/release/juliars --minimal-prelude examples/mandelbrot.jl \
    --emit-binary target/mandelbrot_aot
$ target/mandelbrot_aot
  9.4e-5 seconds
Mandelbrot Set (50x25):

                              .
                              . .
                              .+
                             ###+.
                        .   .####.
                       .#++#########....
                      ..##############.
            .        ..################..
             ...... .##################.
            .#######.###################
          ...##########################.
#####################################..
          ...##########################.
            .#######.###################
             ...... .##################.
            .        ..################..
                      ..##############.
                       .#++#########....
                        .   .####.
                             ###+.
                              .+
                              . .
                              .

Build juliars from PowerShell with the same Cargo command. Windows executable names use the .exe suffix:

cargo build --release -p subset_julia_vm --features aot --bin juliars
.\target\release\juliars.exe --minimal-prelude examples\mandelbrot.jl --emit-binary target\mandelbrot_aot.exe
.\target\mandelbrot_aot.exe

Rust and the MSVC build tools must be installed. Run the commands from a Developer PowerShell for Visual Studio so that the MSVC linker and runtime libraries are available. The Cranelift backend also supports Windows/MSVC and looks for link.exe or lld-link when linking native artifacts.

The default Rust backend currently builds the generated executable but fails to copy it to the --emit-binary destination on Windows because it looks for the temporary executable without its .exe suffix. Until that is fixed, generating Rust source with -o output.rs remains available, while the complete --emit-binary command above is expected to fail during the final copy step (Issue #11809).

--minimal-prelude is currently required for this example. The full prelude still includes Base paths that reach unsupported AoT BigInt/parametric constructor code, even though the Mandelbrot program itself can compile through the minimal AoT prelude.

For the full set of AoT options (Cranelift backend, object/library output, C ABI exports, etc.), see docs/CLI.md or run juliars --help.

Build the WASM package for the Web Playground as follows.

$ scripts/wasm_build_with_cache.sh --target web --out-dir ./web/pkg
$ cd web
$ python3 server.py
Serving at http://localhost:8080

This script generates and embeds the prelude/Base caches, then builds subset_julia_vm_web with wasm-pack. See docs/CLI.md for details.

• docs/CLI.md: detailed CLI reference, cache instructions, Rust API, C ABI / iOS, WebAssembly, tests, audits
• docs/vm/: architecture, implementation status, testing and audit policies, etc.

Key documents:

• docs/vm/ARCHITECTURE_OVERVIEW.md
• docs/vm/CHECKLISTS.md
• docs/vm/TESTING_GUIDE.md
• docs/vm/STATUS.md
• docs/vm/DONE.md
• docs/vm/UNIMPLEMENTED.md
• docs/vm/PURE_JULIA_DESIGN.md
• docs/vm/WORKAROUNDS.md
• docs/vm/CODE_AUDITS.md