From 1812effbd7b24e9e82aa80d232321b6eadc3b1e7 Mon Sep 17 00:00:00 2001
From: derped <derped@ophanim.de>
Date: Sat, 30 Nov 2024 21:10:07 +0100
Subject: [PATCH] fn.meetsConDo: improve performance and add documentation.

---
 fn.nix | 45 ++++++++++++++++++++++++++++++++++++---------
 1 file changed, 36 insertions(+), 9 deletions(-)

diff --git a/fn.nix b/fn.nix
index 48ec761..fb3c65c 100644
--- a/fn.nix
+++ b/fn.nix
@@ -65,17 +65,44 @@ rec {
 
   # Not sure how list operations are implemented in Nix
   # This might be a tad bit inefficient.
-  # TODO: look for better implementation (map is a builtin function so checking that probably won't help)
   # Sequentially checks elements of list (l) for condition (cond) and executes do on first match.
+  /**
+    Run lambda "(do element)" on the first element of list "l" where (cond element) returns true otherwise return false.
+
+    # Type
+    ```
+    meetsConDo :: (any -> bool) -> (any -> any) -> [any] -> any
+    ```
+
+    # Arguments:
+    - [cond] Condition  function
+    - [do] Function to run on element if cond returns true
+    - [list] List of elements
+
+    # Example:
+    ```nix
+    meetsConDo (element: element >= 5) (element: element + 1) [ 4 2 0 5 1 ]
+    => 6
+
+    meetsConDo (element: element >= 5) (element: element + 1) [ 4 2 0 1 ]
+    => false
+    ```
+  */
   meetsConDo =
-    cond: do: l:
-    ifelse (l == [ ]) false (
-      let
-        h = head l;
-        t = tail l;
-      in
-      ifelse (cond h) (do h) (meetsConDo cond do t)
-    );
+    cond: do: list:
+    let
+      listLen = length list;
+      meetsConDo' =
+        currentIndex:
+        ifelse (currentIndex == listLen) false (
+          let
+            head = elemAt list currentIndex;
+          in
+          ifelse (cond head) (do head) (meetsConDo' (currentIndex + 1))
+        );
+    in
+    meetsConDo' 0;
+
   deps =
     p:
     ifelse (isAttrs p) (filter isAttrs (