Install with nix

This is one way to use rocks.nvim with nixpkgs.

We can configure rocks.nvim to use packages installed by nix such as luarocks or luarocks plugins via:

local custom_luarocks_config_filename = vim.fn.stdpath('config') .. '/luarocks-config-generated.lua'
local luarocks_config_fn = assert(loadfile(custom_luarocks_config_filename))

{
    luarocks_binary = nix_deps.luarocks_executable,
    luarocks_config = luarocks_config_fn(),
    _log_level = vim.log.levels.TRACE,
}

where custom_luarocks_config_filename is generated via nix. This is an example of the file generated by home-manager:

  xdg.configFile = {
    "nvim/lua/generated-by-nix.lua" =
      let
        luaInterpreter = config.programs.neovim.package.lua;
      in
      {
        enable = true;
        text = ''
          local M = {}
          M.gcc_path = "${pkgs.gcc}/bin/gcc"
          M.lua_interpreter = "${luaInterpreter}"
          M.luarocks_executable = "${luaInterpreter.pkgs.luarocks_bootstrap}/bin/luarocks"
          return M
        '';
      };

    # TODO use pkgs.lua.pkgs.luaLib.generateLuarocksConfig
    "nvim/luarocks-config-generated.lua" =
      let
        luaInterpreter = config.programs.neovim.package.lua;
        luarocksStore = luaInterpreter.pkgs.luarocks;
        luacurlPkg = luaInterpreter.pkgs.lua-curl;

        luarocksConfigAttr =
          pkgs.lua.pkgs.luaLib.generateLuarocksConfig ({ externalDeps = [ pkgs.curl.dev ]; })
          // {
            lua_version = "5.1";
          };

        luarocksConfigAttr = lib.recursiveUpdate luarocksConfigAttr {
          rocks_trees = [
            ({
              name = "rocks.nvim";
              root = "/home/teto/.local/share/nvim/rocks";
            })
            ({
              name = "rocks-generated.nvim";
              root = "${luarocksStore}";
            })
            ({
              name = "lua-curl";
              root = "${luacurlPkg}";
            })
            ({
              name = "sqlite.lua";
              root = "${luaInterpreter.pkgs.sqlite}";
            })
          ];

          # to help some package need variables for lib-curl.lua to be installable
          variables = {
               # MYSQL_INCDIR = "${libmysqlclient.dev}/include/mysql";
               # MYSQL_LIBDIR = "${libmysqlclient}/lib/mysql";
          };

        };

        luarocksConfigStr = (lib.generators.toLua { asBindings = false; } luarocksConfigAttr);
      in
      {
        enable = true;
        text = "return ${luarocksConfigStr}";
      };
  };