Building the compiler

Beans is self-hosted: the compiler is written in Beans. To build it from source you need an existing beansc to compile it with. The build is driven by the project Makefile, and compiler/version.h is the single version source.

What you need

• clang
• lld
• make
• git

On Debian or Ubuntu:

sudo apt-get install clang lld make git

On macOS, native builds also need the command-line tools:

xcode-select --install

Building on a public checkout

A public checkout has no private bootstrap, so make builds build/beansc using an already-installed beansc: the one on your PATH, or at $BEANS_HOME/bin/beansc. Under the hood it runs:

beansc build compiler/beans/main.b -o build/beansc.new

The full loop:

# 1. install a release compiler first (the one-line installer)
# 2. get the source
git clone https://github.com/beans-lang/beans.git
cd beans
# 3. build
make
# 4. check it
./build/beansc --version
./build/beansc run examples/hello.b

Choose which compiler bootstraps the build with BEANSC_BOOT:

make BEANSC_BOOT=/path/to/beansc

See Install Beans for the one-line installer.

The C++ bootstrap

With the private C++ bootstrap submodule present, make runs the full stage0 -> stage1 -> stage2 -> stage3 chain:

• beansc0 is the C++ stage-0 compiler.
• Stages 2 and 3 must be byte-identical. That fixed point proves the self-hosted compiler reproduces itself.

make test adds the differential gates on top (see Running the tests).

beansc0 is never installed, never packaged, and never on your PATH. It only exists to bootstrap the build.

Installing

sudo make install PREFIX=/usr/local

This installs beansc (never beansc0), the runtime sources, and the standard library.

See Running the tests and Contributing for the change workflow.