Makam is a dialect of lambda Prolog created and maintained by Antonis Stampoulis, more information here. This is an attempt to use it to define the semantics of the Nickel language.
He distributes it through NPM, and on the repo there's information on how to get it working.
We use the node2nix helper, there's a PR to add it to nixpkgs, but for now this simple config should help.
Just nix-build -A makam and then result/bin/makam ./src/init.makam -. Or run result/bin/makam src/init.makam src/examples.makam to run the examples.
Run node2nix --nodejs-12 -c makam-composition.nix on the makam-spec directory