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diff --git a/users/sterni/nix/fun/default.nix b/users/sterni/nix/fun/default.nix
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+++ b/users/sterni/nix/fun/default.nix
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+{ depot, lib, ... }:
+
+let
+
+  inherit (lib)
+    id
+    ;
+
+  # Simple function composition,
+  # application is right to left.
+  rl = f1: f2:
+    (x: f1 (f2 x));
+
+  # Compose a list of functions,
+  # application is right to left.
+  rls = fs:
+    builtins.foldl' (fOut: f: lr f fOut) id fs;
+
+  # Simple function composition,
+  # application is left to right.
+  lr = f1: f2:
+    (x: f2 (f1 x));
+
+  # Compose a list of functions,
+  # application is left to right
+  lrs = x: fs:
+    builtins.foldl' (v: f: f v) x fs;
+
+  # Warning: cursed function
+  #
+  # Check if a function has an attribute
+  # set pattern with an ellipsis as its argument.
+  #
+  # s/o to puck for discovering that you could use
+  # builtins.toXML to introspect functions more than
+  # you should be able to in Nix.
+  hasEllipsis = f:
+    builtins.isFunction f &&
+    builtins.match ".*<attrspat ellipsis=\"1\">.*"
+      (builtins.toXML f) != null;
+
+in
+
+{
+  inherit (lib)
+    fix
+    flip
+    const
+    ;
+
+  inherit
+    id
+    rl
+    rls
+    lr
+    lrs
+    hasEllipsis
+    ;
+}