unosolo

Work-in-progress Rust application that converts C++ header-only libraries to single self-contained headers.

Disclaimer

This is my first Rust project, mainly created to start getting used to the language. My intention is to improve unosolo as I get better with Rust and the final goal is being able to successfully use it on popular libraries. (If you need a full-fledged customizable preprocessor implementation, check out pcpp.)

I also do not encourage people to create single-header libraries and use those in their projects: they're mainly useful when dealing with very complicated build systems or when experimenting on an online compiler that doesn't allow users to easily import multiple files.

Contributions and code reviews are welcome!

Build instructions

git clone https://github.com/SuperV1234/unosolo
cd unosolo
cargo build

• cargo run -- args... can be used to build&run unosolo.

• cargo install can be used to install unosolo on the user's system.

Overview

Given a set of paths containing the C++ header-only library's header files and a "top-level include" file where the graph traversal will start from, unosolo outputs a self-contained single-header version of the library to stdout. Here's the clap-rs auto-generated help:

unosolo 0.1.1
Vittorio Romeo <[email protected]>
transforms a C++ header-only library in a self-contained single header.

USAGE:
    unosolo [FLAGS] [OPTIONS] --topinclude <top_include>

FLAGS:
    -h, --help       Prints help information
    -V, --version    Prints version information
    -v, --verbose    Enable verbose mode

OPTIONS:
    -p, --paths <paths>...            Include paths [default: .]
    -t, --topinclude <top_include>    Top-level include file path (entrypoint)

Use cases

scelta

unosolo is currently able to transform scelta, my latest C++17 header-only library, to a single-header version. In fact, I've used unosolo to add two badges to scelta's README that allow users to try the library either on wandbox or on godbolt. This idea was taken from Michael Park's excellent variant implementation: mpark::variant.

The command used to transform scelta was:

unosolo -p"./scelta/include" -v -t"./scelta/include/scelta.hpp" > scelta_single_header.hpp

It produced this abomination.

vrm_core and vrm_pp

Since 0.1.1, unosolo supports multiple library include paths and "absolute #include directives". My vrm_core library, which depends on vrm_pp, can be transformed to a single header as follows:

git clone https://github.com/SuperV1234/vrm_pp.git
git clone https://github.com/SuperV1234/vrm_core.git
unosolo -p"./vrm_pp/include" "./vrm_core/include" -t"./vrm_core/include/vrm/core.hpp" > vrm_core_sh.hpp

It produced this beauty.

boost::hana

A single-header version of boost::hana can be created using unosolo as follows:

git clone https://github.com/boostorg/hana
unosolo -p"./hana/include" -t"./hana/include/boost/hana.hpp" > hana_sh.hpp

I haven't tested it very thorougly, but I compiled the example on hana's README without any hiccups.