Installing & Developing

Getting fol

fol is the only binary you install by hand — everything else it fetches itself. Take the fol-v<version>-<target> asset from a release, drop it on your PATH, and set your home:

$ curl -fL -o ~/.local/bin/fol \
    https://github.com/fol-lang/fol/releases/download/v0.2.1/fol-v0.2.1-x86_64-linux
$ chmod +x ~/.local/bin/fol
$ export FOL_HOME="$HOME/.fol"        # add to your shell profile

From that moment a plain fol code run inside any pinned project fetches the right toolchain automatically. To install one ahead of time:

$ fol self install 0.2.1
fetched fol 0.2.1 -> ~/.fol/toolchains/v0.2.1
$ fol self default 0.2.1
default toolchain is now 0.2.1

Prefer keeping everything project-local? Skip FOL_HOME entirely — inside a project the manager uses <project>/.fol/toolchain as its home, so the toolchain sits beside the project’s build outputs and nothing global exists.

Working on FOL itself

A source checkout becomes a first-class toolchain through a link — no copying, always fresh:

$ fol self link dev ~/code/fol
linked toolchain 'dev' -> /home/you/code/fol
$ fol self default dev

A linked toolchain resolves its folc from the checkout’s target/release/folc or target/debug/folc — whichever was built most recently — and its std and runtime straight from the live source tree. Rebuild the compiler, and every fol invocation immediately uses it.

To freeze a source build into a normal, immutable toolchain instead (useful for testing the install flow offline):

$ cargo build --release --bin folc && cargo build --release -p fol-self
$ fol self install 0.2.2 --from .
installed fol 0.2.2 -> ~/.fol/toolchains/v0.2.2 (from /home/you/code/fol)

Releasing

Pushing a v* tag runs the release workflow, which builds folc and fol on every supported Linux target, stages {folc, std/, runtime/}, and uploads:

• fol-compiler-and-lib-v<version>-<target>.tar.gz
• fol-v<version>-<target>

The tarball layout is a contract: fol self install unpacks it verbatim into $FOL_HOME/toolchains/v<version>/, and an integration test pins the workflow to that layout.