@hackage cabal2nix1.7

This utility converts Cabal files into Nix build instructions. The commandline syntax is:

cabal2nix cabal-file-uri [sha256-hash]

The first argument is the path to the cabal file. That path can be an HTTP URL or local file path. For example:

cabal2nix http://hackage.haskell.org/packages/archive/cabal2nix/1.7/cabal2nix.cabal
cabal2nix file:///tmp/cabal2nix.cabal
cabal2nix /tmp/cabal2nix.cabal 0m7zgsd1pxmw504xpvl7dg25ana6dkk1mcyjj4c1wdbkvhvbn3gn

The second argument -- the hash of the source tarball -- is optional. If it's not specified, cabal2nix calls nix-prefetch-url to determine the hash automatically. This causes network traffic, obviously.