From e4dc35ec742a0e93d148a5048de5f24a14eff4d2 Mon Sep 17 00:00:00 2001
From: "jian.han" <jian.han@neds.com>
Date: Thu, 11 Jan 2018 15:19:31 +1000
Subject: [PATCH] first class function example

---
 functions/first_class/main.go | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)
 create mode 100644 functions/first_class/main.go

diff --git a/functions/first_class/main.go b/functions/first_class/main.go
new file mode 100644
index 0000000..5616572
--- /dev/null
+++ b/functions/first_class/main.go
@@ -0,0 +1,32 @@
+package main
+
+import "github.com/davecgh/go-spew/spew"
+
+type Cruncher func(int) int
+
+func mul(n int) int {
+	return n * 2
+}
+
+func add(n int) int {
+	return n + 100
+}
+
+func sub(n int) int {
+	return n - 1
+}
+
+func crunch(nums []int, a ...Cruncher) (rnums []int) {
+	rnums = append(rnums, nums...)
+	for _, f := range a {
+		for i, n := range rnums {
+			rnums[i] = f(n)
+		}
+	}
+	return
+}
+
+func main() {
+	nums := []int{1, 2, 3, 4, 5, 6}
+	spew.Dump(crunch(nums, mul, add, sub))
+}