mkFlake: add self argument which handles system

flake.nix

@@ -21,7 +21,6 @@
         (import ./overlay.nix)
         (import "${lix-module}/overlay.nix" { inherit lix; })
       ];
-      forAllSystems = nixpkgs.lib.genAttrs nixpkgs.lib.systems.flakeExposed;
     in {
       # we don't just use nix.registry.whatever.flake = self
       # the reason for this is to be able to handle a flake.lock containing an entry for this
@@ -43,6 +42,8 @@
       meta.path-entry = "dragnpkgs-unstable=flake:dragnpkgs-unstable";
 
       lib = nixpkgs.lib.extend (final: prev: {
+        forAllSystems = final.genAttrs final.systems.flakeExposed;
+
         licenses = prev.licenses // { fyptl = import ./lib/licenses/fyptl.nix; };
 
         nixosSystem = args:
@@ -172,26 +173,13 @@
             } // builtins.removeAttrs args [ "modules" ]
           );
 
-        mkFlake = flakeDef:
-          let
-            rewritePerSystem = sectionDef: (forAllSystems (system:
-              builtins.mapAttrs (name: value:
-                if final.isDerivation value then
-                  value
-                else
-                  self.legacyPackages.${system}.callPackage value {}
-              ) sectionDef
-            ));
-          in
-            builtins.mapAttrs (name: value:
-              if name == "packages" || name == "legacyPackages" || name == "devShells" then
-                rewritePerSystem value
-              else
-                value
-            ) flakeDef;
+        mkFlake = import ./lib/mkflake/default.nix {
+          pkgs = system: self.legacyPackages.${system};
+          lib = final;
+        };
       });
 
-      legacyPackages = forAllSystems (system:
+      legacyPackages = self.lib.forAllSystems (system:
         let
           unsafeConf = if builtins.hasAttr "extraBuiltins" builtins then (
             let conf = builtins.extraBuiltins; in

lib/mkflake/default.nix

@@ -0,0 +1,28 @@
+{ pkgs, lib }:
+flakeDef:
+let
+  rewritePerSystem = final: sectionDef:
+    lib.forAllSystems (system:
+      builtins.mapAttrs (name: value:
+        if lib.isDerivation value then
+          value
+        else
+          (pkgs system).callPackage value { self = (final system); }
+      ) sectionDef
+    );
+  rewriteAttr = final: name: value:
+    let
+      final_self = system: (builtins.mapAttrs (aname: avalue:
+        if aname == "packages" || aname == "legacyPackages" || aname == "devShells" then
+          avalue.${system}
+        else
+          avalue
+      ) final);
+    in
+      if name == "packages" || name == "legacyPackages" || name == "devShells" then
+        rewritePerSystem final_self value
+      else
+        value;
+  self = builtins.mapAttrs (rewriteAttr self) flakeDef;
+in
+  self