Catapult

A package manager + build system for C++. Like Rust's Cargo but for C++.

Inspired by cargo, CMake, conan, buck2, Meson

This project is very experimental and still in the process of proving out concepts.

Usage

Catapult requires two files in your project: catapult.toml and build.catapult. catapult.toml is comparable to Cargo.toml/package.json and contains metadata about the package. build.catapult is like a CMake script, providing a recipe to build the package.

Dependencies can be specified in catapult.toml:

[dependencies]
zstd = { version = "1.5.5", registry = "https://catapult.trav.bid:6400", channel = "travbid/main"}

build.catapult files are written in starlark, a subset of Python. They should look vaguely familiar if you know CMake:

mylib = add_static_library(
    name = 'mylib',
    sources = ['mylib.cpp'],
    include_dirs_private = zstd.include_dirs,
    include_dirs_public = ['.'],  # Paths are relative to the directory the build.catapult file is in
    link_private = [my_depend.my_depend_lib, zstd.zstd],
)

add_executable(
    name = 'myexe',
    sources = ['main.cpp'],
    links = [mylib],
)

Build and install catapult

cargo install --path .

Build a project with catapult

cd <path to c++ project>
catapult --source-dir . --build-dir build --generator Ninja --toolchain test_data/toolchain_clang.toml
ninja -C build

Supported generators are Ninja and MSVC.

Toolchains

Toolchain files are in TOML format and specify compiler/linker paths and flags. Catapult will try to detect some information about the selected tools. This allows cross-compilation to be treated almost identically to same-platform compilation.

The toolchain file is also where profiles are defined. These can specify flags for example release or debug builds or define your own profile. A profile can be selected with Catapult's --profile flag.

catapult -S . -B build -G Ninja --profile Release

The MSVC generator however will generate a solution including all defined profiles.

Special configurations exist for the MSVC generator. See toolchain_msvc.toml for examples.

A future version of Catapult will auto-generate a toolchain file for you. For now, you can use test_data/toolchain_clang.toml or test_data/toolchain_msvc.toml as a base.

Advantages over other build systems

Catapult is like a combination of CMake + Conan, combined into a single tool.

I've noticed people have difficulty understanding CMake's target-based workflow and dislike its syntax. Conan can be unintuitive and cumbersome to use. Catapult aims to make the target-based workflow easier to understand by using a modern language and to make adding dependencies almost as easy as it is with Cargo or npm. Catapult targets are immutable once created so everything you need to know about a target can be found at a single place e.g. a call to add_static_library.

Bazel / Buck are geared toward building Google/Facebook's gigantic monorepos and don't really solve the problem of adding third-party dependencies. Like Catapult, they also use Starlark as a build language. However, their dependencies are specified as strings. Catapult specifies dependencies as objects, potentially allowing intellisense to suggest targets and earlier erroring with more useful messages.

Catapult has some similarities with Meson. I found Meson to be too opinionated for a build system and didn't like how it managed subprojects.