go.blog/slices: first draft of slices blog post

It's an exposition of append.
Still pretty rough but the programs run.

Fixes golang/go#4055.

R=golang-dev, adg, dan.kortschak, 0xjnml, mirtchovski, bradfitz
CC=golang-dev
https://golang.org/cl/13899043

1 files changed, 23 insertions, 0 deletions

diff --git a/content/slices/prog030.go b/content/slices/prog030.go
new file mode 100644
index 0000000..ee21e09
--- /dev/null
+++ b/content/slices/prog030.go
@@ -0,0 +1,23 @@
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+import (
+	"fmt"
+)
+
+var buffer [256]byte
+var slice []byte = buffer[100:150]
+
+func PtrSubtractOneFromLength(slicePtr *[]byte) {
+	slice = *slicePtr
+	*slicePtr = slice[0 : len(slice)-1]
+}
+
+func main() {
+	fmt.Println("Before: len(slice) =", len(slice))
+	PtrSubtractOneFromLength(&slice)
+	fmt.Println("After:  len(slice) =", len(slice))
+}