Supplying libraries to callCabal2nix

Help
1

I need a shell where I can run (not develop) some some Haskell programs I wrote. So I created the following shell.nix.

with (import <nixpkgs> {});
let
  pandoc-linear-table = haskellPackages.callCabal2nix "pandoc-linear-table" /home/amy/github/pandoc-linear-table {};
  pandoc-logic-proof = haskellPackages.callCabal2nix "pandoc-logic-proof" /home/amy/github/pandoc-logic-proof {};
  pandoc-columns = haskellPackages.callCabal2nix "pandoc-columns" /home/amy/github/pandoc-columns {};
  pandoc-maths-web = haskellPackages.callCabal2nix "pandoc-maths-web" /home/amy/github/pandoc-maths-web {};
in
mkShell {
  buildInputs = [
                  pkgs.lighttpd
                  pkgs.python310Packages.httpserver
                  pkgs.pandoc
                  pandoc-linear-table
                  pandoc-logic-proof
                  pandoc-columns
#                  pandoc-maths-web
                ];
}

This works fine with that one line commented out.

Now, the pandoc-linear-table, pandoc-logic-proof, and pandoc-columns packages provide libraries as well as executables. I only need the executable in my shell.

The problem is that pandoc-maths-web depends on those libraries in order to build, so if I uncomment that line, I get an error message. How can I include pandoc-maths-web in my shell?

What I’ve tried: I guess what I need to do is to add overrides to the arguments for callCabal2nix. So I tried this, but I wasn’t really sure of the syntax.

with (import <nixpkgs> {});
let
  pandoc-linear-table = haskellPackages.callCabal2nix "pandoc-linear-table" /home/amy/github/pandoc-linear-table {};
  pandoc-logic-proof = haskellPackages.callCabal2nix "pandoc-logic-proof" /home/amy/github/pandoc-logic-proof {};
  pandoc-columns = haskellPackages.callCabal2nix "pandoc-columns" /home/amy/github/pandoc-columns {};
  pandoc-maths-web = haskellPackages.callCabal2nix "pandoc-maths-web" /home/amy/github/pandoc-maths-web
                       {
                         overrides = {
                                       pandoc-linear-table = haskellPackages.callCabal2nix "pandoc-linear-table" /home/amy/github/pandoc-linear-table {};
                                       pandoc-logic-proof = haskellPackages.callCabal2nix "pandoc-logic-proof" /home/amy/github/pandoc-logic-proof {};
                                       pandoc-columns = haskellPackages.callCabal2nix "pandoc-columns" /home/amy/github/pandoc-columns {};
                                     };
                       };
in
mkShell {
  buildInputs = [
                  pkgs.lighttpd
                  pkgs.python310Packages.httpserver
                  pkgs.pandoc
                  pandoc-linear-table
                  pandoc-logic-proof
                  pandoc-columns
                  pandoc-maths-web
                ];
}

However, it still can’t seem to find my libraries.

✦ ❯ nix-shell
error: anonymous function at /nix/store/030vdxsj21cwlzzga61ncrgk552m9ssm-cabal2nix-pandoc-maths-web/default.nix:1:1 called without required argument 'pandoc-linear-table'

       at /nix/store/g0xys7v6as2jaifxp1lkr9d7pbaksr03-nixos/nixos/pkgs/development/haskell-modules/make-package-set.nix:97:40:

           96|       # this wraps the `drv` function to add a `overrideScope` function to the result.
           97|       drvScope = allArgs: ensureAttrs (drv allArgs) // {
             |                                        ^
           98|         overrideScope = f:
(use '--show-trace' to show detailed location information)
1 Like
2

Dependencies are passed directly, i.e. callCabal2nix "my-pkg.cabal.nix" ./path { inherit my-dependency; }. Note that it may be easier to create a version of haskellPackages that is extended by your local packages via an overlay which allows the dependencies to be resolved automatically.

3 Likes