initial checkin

Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com>

monoid/function.go

@@ -0,0 +1,14 @@
+package monoid
+
+import (
+	F "github.com/ibm/fp-go/function"
+	S "github.com/ibm/fp-go/semigroup"
+)
+
+// FunctionMonoid forms a monoid as long as you can provide a monoid for the codomain.
+func FunctionMonoid[A, B any](M Monoid[B]) Monoid[func(A) B] {
+	return MakeMonoid(
+		S.FunctionSemigroup[A, B](M).Concat,
+		F.Constant1[A](M.Empty()),
+	)
+}