Darcs is a distributed version control system (DVCS) that is focuses on patches instead of snapshots. At the time of writing, Nix flakes does not & cannot support Darcs input pinning requiring an input pinner like Nixtamal to automate it.

How to pin a Darcs repository with Nix + Nixtamal using htmlq

Smederee is an open source Darcs forge written in Scala. There is not an implicit “tags” page & an RSS feed exists but is only the last n patches which doesn’t guarantee a tag is found. However, the web UI exposes the latest tag specifically.

Latest tag from a smeder.ee using htmlq 

// manifest.kdl
inputs {
	smederee {
		darcs {
			repository "https://smeder.ee/~wegtam/smederee"
		}
		fresh-cmd {
			$ curl -sL "https://smeder.ee/~wegtam/smederee"
			| htmlq .repo-summary-description
			| grep TAG
			| htmlq --text a
			| cut -f2 "-d' '"
		}
	}
}