As a prerequisite, Python must be installed, see Python on Mac.
To install BornAgain on MacOS, one should use the official MLZ Homebrew Tap hosted at https://jugit.fz-juelich.de/mlz/homebrew/.
First, add the tap to the local Homebrew taps via
$ brew tap mlz/homebrew https://jugit.fz-juelich.de/mlz/homebrew/
After that, brew will be able to work with formulae in mlz/homebrew as if they were
in homebrew-core canonical repository.
To install BornAgain v22 from the tap, use
$ brew install mlz/homebrew/bornagain@22
To obtain detailed information about the BornAgain installation, use
$ bornagain_info
This will display the paths to BornAgain installation, the examples, the Python wheel and the build log.
Run the BornAgain GUI (with Python support) via
$ bornagain
To use BornAgain as a Python package, install the wheel via
$ python3 -m pip install /path/to/bornagain/python/wheel
The path to the Python wheel is obtained via the above-mentioned command, bornagain_info