Getting started

SLC is a Cargo workspace. Building it produces the slc binary.

git clone https://github.com/KeenS/slc.git
cd slc
cargo build

The binary is target/debug/slc. A release build is cargo build --release, and the binary is then target/release/slc. Either one is what the rest of this book means by slc. cargo run -- from the repository root runs the debug binary and passes the words after -- to it.

Run, compile, check, and format

slc run examples/basics/hello.sl
slc check examples/basics/hello.sl
slc fmt examples/basics/hello.sl

slc run checks the program and then runs it. By default it compiles to a native x86-64 ELF. On any other host it uses the interpreter. slc run --interpret evaluates the same program on the abstract machine. Flags belong before the file name. Words after the file are the program's own arguments.

slc compile writes that executable and does not run it. -o names the file. With no -o, the name is the source stem in the current directory. --fuel N is the executable's step bound. The words passed to the executable are the program's arguments.

slc compile -o hello examples/basics/hello.sl
./hello

slc check reports what run would report before evaluating, and evaluates nothing. A file with no main checks as a library. The command exits non-zero when a file fails.

slc fmt rewrites a file into the one layout: four-space indentation, lines within 100 columns, a semicolon after every statement except a block's last expression, and a comma after every of or mu arm. --check fails when a file would change and writes nothing. --stdout prints the result.

slc fmt --check examples/basics/*.sl
slc fmt --stdout examples/basics/hello.sl

slc run --fuel N stops after N steps. With no --fuel, a run is bounded by memory. --fuel 0 runs no SLC code.

The version line is slc --version.

What a program is

A program is one or more .sl files. The root file declares main. The prelude is in every program: Bool, arithmetic, println, and the IO effect. The standard library is reached by a path, such as list::length, or brought in with cite.

The next chapter is the smallest program that prints a line and exits.