From 3e7a328db725ae2958d4df050f37df315deaa311 Mon Sep 17 00:00:00 2001
From: gusty <1261319+gusty@users.noreply.github.com>
Date: Sat, 13 Jan 2024 07:29:13 +0100
Subject: [PATCH] + map3Shortest and zip3shortest to Array and ResizeArray

---
 src/FSharpPlus/Extensions/Array.fs       | 22 ++++++++++++++++++++++
 src/FSharpPlus/Extensions/ResizeArray.fs | 24 ++++++++++++++++++++++++
 2 files changed, 46 insertions(+)

diff --git a/src/FSharpPlus/Extensions/Array.fs b/src/FSharpPlus/Extensions/Array.fs
index 26a13ab0a..5113cbd70 100644
--- a/src/FSharpPlus/Extensions/Array.fs
+++ b/src/FSharpPlus/Extensions/Array.fs
@@ -238,6 +238,15 @@ module Array =
 
         Array.init (min a1.Length a2.Length) (fun i -> f a1.[i] a2.[i])
     
+    /// <summary>Safely build a new array whose elements are the results of applying the given function
+    /// to each of the elements of the three arrays pairwise.</summary>
+    /// <remark>If one array is shorter, excess elements are discarded from the right end of the longer array.</remark>
+    let map3Shortest f (a1: 'T1 []) (a2: 'T2 []) (a3: 'T3 []) =
+        raiseIfNull (nameof a1) a1
+        raiseIfNull (nameof a2) a2
+        raiseIfNull (nameof a3) a3
+        Array.init (min a1.Length a2.Length |> min a3.Length) (fun i -> f a1.[i] a2.[i] a3.[i])
+    
     /// <summary>
     /// Zip safely two arrays. If one array is shorter, excess elements are discarded from the right end of the longer array. 
     /// </summary>
@@ -250,6 +259,19 @@ module Array =
 
         Array.init (min a1.Length a2.Length) (fun i -> a1.[i], a2.[i])
 
+    /// <summary>
+    /// Zip safely three arrays. If one array is shorter, excess elements are discarded from the right end of the longer array. 
+    /// </summary>
+    /// <param name="a1">First input array.</param>
+    /// <param name="a2">Second input array.</param>
+    /// <param name="a3">Third input array.</param>
+    /// <returns>Array with corresponding tuple of input arrays.</returns>
+    let zip3Shortest (a1: array<'T1>) (a2: array<'T2>) (a3: array<'T3>) =
+        raiseIfNull (nameof a1) a1
+        raiseIfNull (nameof a2) a2
+        raiseIfNull (nameof a3) a3
+        Array.init (min a1.Length a2.Length |> min a3.Length) (fun i -> a1.[i], a2.[i], a3.[i])
+
     /// <summary>Same as choose but with access to the index.</summary>
     /// <param name="mapping">The mapping function, taking index and element as parameters.</param>
     /// <param name="source">The input array.</param>
diff --git a/src/FSharpPlus/Extensions/ResizeArray.fs b/src/FSharpPlus/Extensions/ResizeArray.fs
index 330b9b630..72de31931 100644
--- a/src/FSharpPlus/Extensions/ResizeArray.fs
+++ b/src/FSharpPlus/Extensions/ResizeArray.fs
@@ -134,6 +134,16 @@ module ResizeArray =
             ra.Add (f a1.[i] a2.[i])
         ra
     
+    /// <summary>Safely build a new ResizeArray whose elements are the results of applying the given function
+    /// to each of the elements of the three ResizeArrays pairwise.</summary>
+    /// <remark>If one array is shorter, excess elements are discarded from the right end of the longer array.</remark>
+    let map3Shortest f (a1: ResizeArray<'T1>) (a2: ResizeArray<'T2>) (a3: ResizeArray<'T3>) =
+        let len = min a1.Count a2.Count |> min a3.Count
+        let ra = ResizeArray len
+        for i in 0..(len-1) do
+            ra.Add (f a1.[i] a2.[i] a3.[i])
+        ra
+    
     /// <summary>
     /// Zip safely two ResizeArrays. If one ResizeArray is shorter, excess elements are discarded from the right end of the longer ResizeArray. 
     /// </summary>
@@ -146,3 +156,17 @@ module ResizeArray =
         for i in 0..(len-1) do
             ra.Add (a1.[i], a2.[i])
         ra
+
+    /// <summary>
+    /// Zip safely three ResizeArrays. If one ResizeArray is shorter, excess elements are discarded from the right end of the longer ResizeArray.
+    /// </summary>
+    /// <param name="a1">First input ResizeArray.</param>
+    /// <param name="a2">Second input ResizeArray.</param>
+    /// <param name="a3">Third input ResizeArray.</param>
+    /// <returns>ResizeArray with corresponding pairs of input ResizeArrays.</returns>
+    let zip3Shortest (a1: ResizeArray<'T1>) (a2: ResizeArray<'T2>) (a3: ResizeArray<'T3>) =
+        let len = min a1.Count a2.Count |> min a3.Count
+        let ra = ResizeArray len
+        for i in 0..(len-1) do
+            ra.Add (a1.[i], a2.[i], a3.[i])
+        ra