anchor.diff:          source = mkIf (config.body != null) (
             mkDefault (pkgs.writeTextFile {
               inherit name;
  -            text = ''
  -            function ${name}
  -              ${config.body}
  -            end
  -            '';
  +            text = textGen name config.body;
               executable = true;
             })
           );
  
positive.code:     };
  
      programs.fish.functions = mkOption {
        type = types.attrsOf fileType;
        default = {};
        description = ''
          Functions to add to fish.
        '';
      };
    };
  
negative.code:     mapAttrsToList (k: v: "alias ${k}='${v}'") cfg.shellAliases
    );
  
    fileType = textGen: types.submodule (
      { name, config, ... }: {
        options = {
          body = mkOption {
            default = null;
            type = types.nullOr types.lines;
            description = "Body of the file.";
          };
  
          source = mkOption {
  