xplr: support multiple plugins in cfg.plugins

Fixes ##4520

Co-authored-by: Arijit Basu <11632726+sayanarijit@users.noreply.github.com>

modules/programs/xplr.nix

@@ -1,8 +1,7 @@
 { config, lib, pkgs, ... }:
 let
   inherit (lib)
-    concatStringsSep types mkIf mkOption mkEnableOption mkPackageOption
-    literalExpression;
+    types mkIf mkOption mkEnableOption mkPackageOption literalExpression;
 
   cfg = config.programs.xplr;
 
@@ -10,21 +9,39 @@ let
     version = '${cfg.package.version}'
   '';
 
-  # We provide a default version line within the configuration file, which is
-  # obtained from the package's attributes. Merge the initial configFile, a
-  # mapped list of plugins and then the user defined configuration to obtain the
-  # final configuration.
-  pluginPath = if cfg.plugins != [ ] then
-    (''
-      package.path=
-    '' + (concatStringsSep " ..\n"
-      (map (p: ''"${p}/init.lua;${p}/?.lua;"'') cfg.plugins)) + ''
-         ..
-        package.path
-      '')
+  # If `value` is a Nix store path, create the symlink `/nix/store/newhash/${name}/*` 
+  # to `/nix/store/oldhash/*` and returns `/nix/store/newhash`.
+  wrapPlugin = name: value:
+    if lib.isStorePath value then
+      pkgs.symlinkJoin {
+        name = name;
+        paths = [ value ];
+        postBuild = ''
+          mkdir '${name}'
+          mv $out/* '${name}/'
+          mv '${name}' $out/
+        '';
+      }
+    else
+      builtins.dirOf value;
+
+  makePluginSearchPath = p: "${p}/?/init.lua;${p}/?.lua";
+
+  pluginPath = if cfg.plugins != { } then
+    let
+      wrappedPlugins = lib.mapAttrsToList wrapPlugin cfg.plugins;
+      searchPaths = map makePluginSearchPath wrappedPlugins;
+      pluginSearchPath = lib.concatStringsSep ";" searchPaths;
+    in (''
+      package.path = "${pluginSearchPath};" .. package.path
+    '')
   else
     "\n";
 
+  # We provide a default version line within the configuration file, which is
+  # obtained from the package's attributes. Merge the initial configFile, a
+  # mapped list of plugins and then the user defined configuration to obtain
+  # the final configuration.
   configFile = initialConfig + pluginPath + cfg.extraConfig;
 in {
   meta.maintainers = [ lib.maintainers.NotAShelf ];
@@ -35,15 +52,25 @@ in {
     package = mkPackageOption pkgs "xplr" { };
 
     plugins = mkOption {
-      type = with types; nullOr (listOf (either package str));
-      default = [ ];
-      defaultText = literalExpression "[]";
+      type = with types; nullOr (attrsOf (either package str));
+      default = { };
+      defaultText = literalExpression "{ }";
       description = ''
-        Plugins to be added to your configuration file.
+        An attribute set of plugin paths to be added to the [package.path]<https://www.lua.org/manual/5.4/manual.html#pdf-package.path> of the {file}`~/config/xplr/init.lua` configuration file.
 
-        Must be a package, an absolute plugin path, or string to be recognized
-        by xplr. Paths will be relative to
-        {file}`$XDG_CONFIG_HOME/xplr/init.lua` unless they are absolute.
+        Must be a package or string representing the plugin directory's path. 
+        If the path string is not absolute, it will be relative to {file}`$XDG_CONFIG_HOME/xplr/init.lua`.
+      '';
+      example = literalExpression ''
+        {
+          wl-clipboard = fetchFromGitHub {
+            owner = "sayanarijit";
+            repo = "wl-clipboard.xplr";
+            rev = "a3ffc87460c5c7f560bffea689487ae14b36d9c3";
+            hash = "sha256-I4rh5Zks9hiXozBiPDuRdHwW5I7ppzEpQNtirY0Lcks=";
+          }
+          local-plugin = "/home/user/.config/plugins/local-plugin";
+        };
       '';
     };