lib.converge: optimise

2019-04-17 15:55:57 +01:00 · 2019-04-17 15:55:57 +01:00 · 7ed977e60d
commit 7ed977e60d
parent 6336f9e6ea
1 changed files with 6 additions and 3 deletions
--- a/lib/fixed-points.nix
+++ b/lib/fixed-points.nix
@ -30,9 +30,12 @@ rec {
  #     nix-repl> converge (x: x / 2) 16
  #     0
  converge = f: x:
-    if (f x) == x
-    then x
-    else converge f (f x);
+    let
+      x' = f x;
+    in
+      if x' == x
+      then x
+      else converge f x';

  # Modify the contents of an explicitly recursive attribute set in a way that
  # honors `self`-references. This is accomplished with a function