gen-product

gen-product is pure graph products for Nix. It builds the four standard graph products — Cartesian, tensor (direct), strong, and lexicographic — over accessor-graphs, the same caller-supplies-the-structure convention gen-graph itself uses.

The problem it owns: combining two graphs — a topology and a role assignment, say — into one product graph is standard graph theory, and standard graph theory is exactly the kind of thing worth getting from a library instead of reimplementing per caller. gen-product is the four products, correct, with no opinion about what your nodes represent.

It depends only on gen-prelude. No roster member currently builds on it — like gen-dispatch, it’s meant to be taken directly.

Take it alone

{
  inputs.gen-product.url = "github:sini/gen-product";
  # gen-product pulls in gen-prelude transitively — no nixpkgs input required.
}

gen-product.lib is the genProduct attrset. Without flakes:

let genProduct = import (fetchTarball "https://github.com/sini/gen-product/archive/main.tar.gz") { };
in genProduct.cartesian hostFactor userFactor