From f92b7d7480def33c10786204474d060229ca7fd6 Mon Sep 17 00:00:00 2001
From: Raphael Forment <raphael.forment@gmail.com>
Date: Sun, 8 Oct 2023 19:34:09 +0200
Subject: [PATCH] experimenting with high order function application

---
 src/API.ts             | 72 ++++++++++++++++++++++++++++++++++++++++++
 src/ArrayExtensions.ts | 14 ++++++++
 2 files changed, 86 insertions(+)

diff --git a/src/API.ts b/src/API.ts
index c0134f2..66567bf 100644
--- a/src/API.ts
+++ b/src/API.ts
@@ -1750,4 +1750,76 @@ export class UserAPI {
      */
     return array[(this.app.clock.time_position.bar + 1) % array.length];
   };
+
+  // =============================================================
+  // High Order Functions
+  // =============================================================
+
+  public shuffle = <T>(array: T[]): T[] => {
+    /**
+     * Returns a shuffled version of an array.
+     * @param array - The array to shuffle
+     * @returns A shuffled version of the array
+     */
+    return array.sort(() => this.randomGen() - 0.5);
+  };
+
+  public reverse = <T>(array: T[]): T[] => {
+    /**
+     * Returns a reversed version of an array.
+     * @param array - The array to reverse
+     * @returns A reversed version of the array
+     */
+    return array.reverse();
+  };
+
+  public rotate = <T>(n: number): Function => {
+    /**
+     * Returns a partially applied function that rotates an array by n.
+     *
+     */
+
+    return (array: T[]): T[] => {
+      return array.slice(n, array.length).concat(array.slice(0, n));
+    };
+  };
+
+  public repeat = <T>(n: number): Function => {
+    /**
+     * Returns a partially applied function that repeats each element of an array n times.
+     *
+     */
+    return (array: T[]): T[] => {
+      return array.flatMap((x) => Array(n).fill(x));
+    };
+  };
+
+  public repeatOdd = <T>(n: number): Function => {
+    /**
+     * Returns a partially applied function that repeats  each even element of an array n times.
+     *
+     */
+    return (array: T[]): T[] => {
+      return array.flatMap((x, i) => (i % 2 === 0 ? Array(n).fill(x) : x));
+    };
+  };
+
+  public repeatEven = <T>(n: number): Function => {
+    /**
+     * Returns a partially applied function that repeats  each even element of an array n times.
+     *
+     */
+    return (array: T[]): T[] => {
+      return array.flatMap((x, i) => (i % 2 !== 0 ? Array(n).fill(x) : x));
+    };
+  };
+
+  public palindrome = <T>(array: T[]): T[] => {
+    /**
+     * Returns a palindrome of an array.
+     * @param array - The array to palindrome
+     * @returns A palindrome of the array
+     */
+    return array.concat(array.slice(0, array.length - 1).reverse());
+  };
 }
diff --git a/src/ArrayExtensions.ts b/src/ArrayExtensions.ts
index c48344c..69a0323 100644
--- a/src/ArrayExtensions.ts
+++ b/src/ArrayExtensions.ts
@@ -28,6 +28,8 @@ declare global {
     square(): number[];
     sqrt(): number[];
     gen(min: number, max: number, times: number): number[];
+    sometimes(func: Function): number[];
+    apply(func: Function): number[];
   }
 }
 
@@ -39,6 +41,18 @@ export const makeArrayExtensions = (api: UserAPI) => {
     return this.map((x: number) => x * x);
   };
 
+  Array.prototype.sometimes = function (func: Function): number[] {
+    if (api.randomGen() < 0.5) {
+      return func(this);
+    } else {
+      return this;
+    }
+  };
+
+  Array.prototype.apply = function (func: Function): number[] {
+    return func(this);
+  };
+
   Array.prototype.sqrt = function (): number[] {
     /**
      * @returns New array with square roots of values. Throws if any element is negative.