Recoil

Requirements

Recoil transpiles to C, so you need two things on your machine:

• A C compiler — GCC or Clang. The generated C is plain and portable.
• Rebol 3 — the compiler itself is written in Rebol. Use the actively maintained Oldes build of Rebol 3 (the bulk variant is the easiest to start with). Binaries exist for Linux, macOS, the BSDs, Haiku, and Windows.

The Rebol executable is usually called r3 (sometimes rebol3). All commands below use r3.

Get the source

git clone https://codeberg.org/rebolek/recoil.git
cd recoil

Your first program

Create a file called hello.rcl:

; hello.rcl
print "Hello, Recoil!"

Compile and run it:

r3 -s recoil.r3 hello.rcl
./hello

The compiler emits a C file, invokes your C compiler, and produces a native binary next to the source. To see the generated C without building a binary, transpile only:

r3 -s recoil.r3 --transpile hello.rcl

Try it

A slightly bigger program

Bindings are implicitly typed and functions return their last expression:

; sum.rcl
add: func [a [i32!] b [i32!] return: [i32!]] [
    a + b
]

total: add 2 40
print total             ; 42

Read the Language Guide for the full syntax, or skim Recoil by Example for more complete programs.

Building libraries

Recoil can emit shared or static libraries with a generated C header. Mark functions with #export (see Packages & Libraries), then:

# Shared library (name derived from the source file)
r3 -s recoil.r3 --lib mylib.rcl

# Shared library with a custom name
r3 -s recoil.r3 --lib mylib.rcl --name mylib

# Static library
r3 -s recoil.r3 --lib mylib.rcl --static

Note that --lib comes before the source file.

Running the test suite

The project uses its own test runner, RUT. Verify your setup:

# Run the whole suite
r3 -s rut.r3

# A specific test by title
r3 -s rut.r3 -t "Mandelbrot"

# A single test file
r3 -s rut.r3 -F parser.reb

# List available tests
r3 -s rut.r3 --list

Run RUT with r3 -s rut.r3 (not r3 rut.r3), and only one build at a time — RUT enforces a single active runner via a lock.

Next steps