From f6ee9d535f0b8fd760774c137612d423c30274fd Mon Sep 17 00:00:00 2001
From: zimbatm <zimbatm@zimbatm.com>
Date: Sat, 11 Apr 2020 16:45:25 +0200
Subject: [PATCH] adds forAllSupported

---
 default.nix | 26 ++++++++++++++++++++++++++
 flake.nix   |  7 +++++++
 2 files changed, 33 insertions(+)
 create mode 100644 default.nix
 create mode 100644 flake.nix

diff --git a/default.nix b/default.nix
new file mode 100644
index 0000000..2f4c5d4
--- /dev/null
+++ b/default.nix
@@ -0,0 +1,26 @@
+rec {
+  # copied from <nixpkgs/lib>
+  genAttrs = names: f:
+    builtins.listToAttrs (map (n: { name = n; value = f n; }) names);
+
+  # The list of systems supported by nixpkgs and hydra
+  supportedSystems = [
+    "aarch64-linux"
+    "i686-linux"
+    "x86_64-darwin"
+    "x86_64-linux"
+  ];
+
+  # Returns an attribute set with all the supported systems as keys and the
+  # output of the passed function with each system passed to it.
+  #
+  # This is useful in the flake outputs because the outputs return static sets
+  # that map to the different systems.
+  #
+  # Example:
+  #   forAllSupported (x: null)
+  #   > { aarch64-linux = null; i686-linux = null; x86_64-darwin = null;
+  #   > x86_64-linux = null; }
+  # (system -> attrs) -> attrs
+  forAllSupported = genAttrs supportedSystems;
+}
diff --git a/flake.nix b/flake.nix
new file mode 100644
index 0000000..b565074
--- /dev/null
+++ b/flake.nix
@@ -0,0 +1,7 @@
+{
+  description = "Pure Nix flake utility functions";
+  edition = 201909;
+  outputs = { self }: {
+    lib = import ./.;
+  };
+}