Pijul isn't really an "implementation" of that, for many reasons, including the fact that the paper doesn't show an algorithm to implement. However, Pijul was

Pijul isn't really an "implementation" of that, for many reasons, including the fact that the paper doesn't show an algorithm to implement. However, Pijul was inspired by this, with a number of differences, including support for line deletions (which changes everything) and multiple files, which cause many more conflict types. Darcs was another major source of inspiration.