From a619fd24f6f8bc0e053836bdfb3f5e533315a6fa Mon Sep 17 00:00:00 2001
From: Aadhavan Srinivasan <aadhavan@twomorecents.org>
Date: Tue, 29 Oct 2024 20:06:09 -0400
Subject: [PATCH] Added map and reduce functions, and a function to return the
 difference between two sets

---
 misc.go | 36 ++++++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/misc.go b/misc.go
index 1206a57..4d2a5eb 100644
--- a/misc.go
+++ b/misc.go
@@ -52,3 +52,39 @@ func allEqual[T comparable](items ...T) bool {
 	}
 	return true
 }
+
+// Returns all elements in slice A that are NOT in slice B
+func setDifference[T comparable](s1 []T, s2 []T) []T {
+	toReturn := make([]T, 0)
+	for _, val := range s1 {
+		if !slices.Contains(s2, val) {
+			toReturn = append(toReturn, val)
+		}
+	}
+	return toReturn
+}
+
+// Map function - convert a slice of T to a slice of V, based on a function
+// that maps a T to a V
+func Map[T, V any](slc []T, fn func(T) V) []V {
+	toReturn := make([]V, len(slc))
+	for i, val := range slc {
+		toReturn[i] = fn(val)
+	}
+	return toReturn
+}
+
+// Reduce function - reduces a slice of a type into a value of the type,
+// based on the given function.
+func Reduce[T any](slc []T, fn func(T, T) T) T {
+	if len(slc) == 0 {
+		panic("Reduce on empty slice.")
+	}
+	for len(slc) > 1 {
+		v1 := slc[0]
+		v2 := slc[1]
+		slc = slc[1:]
+		slc[0] = fn(v1, v2)
+	}
+	return slc[0]
+}