1 files changed, 80 insertions, 0 deletions
diff --git a/lib/default.nix b/lib/default.nix
new file mode 100644
index 0000000..0d36185
--- /dev/null
+++ b/lib/default.nix
@@ -0,0 +1,80 @@
+{ config, lib, ... }:
+
+let
+  self = config.flake.lib;
+in
+
+{
+
+  flake.lib = {
+    /**
+      Get the derivation attribute of a configuration if needed
+
+      # Type
+
+      ```
+      derivationFrom :: AttrSet -> Derivation
+      ```
+
+      # Arguments
+
+      - [set] A system/home configuration or regular derivation
+    */
+    derivationFrom =
+      deriv:
+      if lib.isDerivation deriv then
+        deriv
+      else
+        deriv.config.system.build.toplevel or deriv.activationPackage;
+
+    /**
+      Check if a derivation or configuration is compatible with the current system
+
+      # Type
+
+      ```
+      isCompatible :: String -> Derivation -> Bool
+      ```
+
+      # Arguments
+
+      - [system] System to check against
+      - [derivation] Derivation to check
+    */
+    isCompatibleWith = system: deriv: (deriv.pkgs or deriv).stdenv.hostPlatform.system == system;
+
+    /**
+      Flatten nested derivations from an attribute set
+
+      Mainly for use with making Flake outputs work in `checks`
+
+      # Example
+
+      ```nix
+      collectNestedDerivations { nixosConfigurations = { my-machine = { }; }; }
+      => { nixosConfigurations-my-machine = { }; }
+
+      # Type
+
+      ```
+      collectNestedDerivations :: String -> AttrSet -> AttrSet
+      ```
+
+      # Arguments
+
+      - [system] System to collect derivations for
+      - [set] Set of (single-level) nested derivations
+    */
+    collectNestedDerivationsFor =
+      system:
+
+      lib.foldlAttrs (
+        acc: attrType: values:
+
+        acc
+        // lib.mapAttrs' (
+          attrName: value: lib.nameValuePair "${attrType}-${attrName}" (self.derivationFrom value)
+        ) (lib.filterAttrs (lib.const (self.isCompatibleWith system)) values)
+      ) { };
+  };
+}