@@ -40,3 +40,29 @@ nix
40`Nix <https://nixos.org/nix/>`_ users should feel free to take a look at
40`Nix <https://nixos.org/nix/>`_ users should feel free to take a look at
41the `nix/shell.nix` file in the repository and use it to provision a suitable
41the `nix/shell.nix` file in the repository and use it to provision a suitable
42environment to build and run the examples.
42environment to build and run the examples.
47+Ubuntu's packages for `ghc`, `cabal`, and `stack` are years out of date.
48+If the instructions above fail for you,
49+try replacing the Ubuntu packages with up-to-date versions.
50+First remove the installed versions:
54+ # remove the obsolete versions
55+ $ sudo apt remove ghc haskell-stack cabal-install
57+Then install fresh versions of the Haskell toolchain
58+using the `ghcup <https://www.haskell.org/ghcup/install/>`_ installer.
60+As of February 2022, one easy way to do this is by running a bootstrap script:
64+ $ curl --proto '=https' --tlsv1.2 -sSf https://get-ghcup.haskell.org | sh
66+The script is interactive and will prompt you for details about what
67+you want installed and where. To install manually,
68+see `the detailed instructions <https://www.haskell.org/ghcup/install/#manual-install>`_.