added Reduce method

go.mod

@@ -1,3 +1,5 @@
 module git.milar.in/milarin/slices
 
-go 1.19
+go 1.19
+
+require git.milar.in/milarin/gmath v0.0.3

go.sum

@@ -1,2 +1,2 @@
-git.milar.in/milarin/channel v0.0.7 h1:cVKtwgH/EE7U+XTHcoFCClJ4LR349KanzjX9xKwRcNg=
+git.milar.in/milarin/gmath v0.0.3 h1:ii6rKNItS55O/wtIFhD1cTN2BMwDZjTBmiOocKURvxM=
-git.milar.in/milarin/channel v0.0.7/go.mod h1:We83LTI8S7u7II3pD+A2ChCDWJfCkcBUCUqii9HjTtM=
+git.milar.in/milarin/gmath v0.0.3/go.mod h1:HDLftG5RLpiNGKiIWh+O2G1PYkNzyLDADO8Cd/1abiE=

reduce.go

@@ -0,0 +1,15 @@
+package slices
+
+import "git.milar.in/milarin/gmath"
+
+func Reduce[T, R any](slice []T, reducer func(current R, v T) R) R {
+	res := new(R)
+	Each(slice, func(v T) {
+		*res = reducer(*res, v)
+	})
+	return *res
+}
+
+func SumReducer[N gmath.Number](a, b N) N {
+	return a + b
+}

reduce_test.go

@@ -0,0 +1,11 @@
+package slices
+
+import (
+	"fmt"
+	"testing"
+)
+
+func TestReduce(t *testing.T) {
+	s := Of(1, 2, 3)
+	fmt.Println(Reduce(s, SumReducer[int]))
+}