sort: add a simpler sort.Interface example
Existing example renamed to Example_sortWrapper.
Fixes #6335.
R=golang-dev, rsc, taj.khattra, r
CC=golang-dev
https://golang.org/cl/13586043
diff --git a/src/pkg/sort/example_wrapper_test.go b/src/pkg/sort/example_wrapper_test.go
new file mode 100644
index 0000000..cf6d74c
--- /dev/null
+++ b/src/pkg/sort/example_wrapper_test.go
@@ -0,0 +1,77 @@
+// Copyright 2011 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 sort_test
+
+import (
+ "fmt"
+ "sort"
+)
+
+type Grams int
+
+func (g Grams) String() string { return fmt.Sprintf("%dg", int(g)) }
+
+type Organ struct {
+ Name string
+ Weight Grams
+}
+
+type Organs []*Organ
+
+func (s Organs) Len() int { return len(s) }
+func (s Organs) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
+
+// ByName implements sort.Interface by providing Less and using the Len and
+// Swap methods of the embedded Organs value.
+type ByName struct{ Organs }
+
+func (s ByName) Less(i, j int) bool { return s.Organs[i].Name < s.Organs[j].Name }
+
+// ByWeight implements sort.Interface by providing Less and using the Len and
+// Swap methods of the embedded Organs value.
+type ByWeight struct{ Organs }
+
+func (s ByWeight) Less(i, j int) bool { return s.Organs[i].Weight < s.Organs[j].Weight }
+
+func Example_sortWrapper() {
+ s := []*Organ{
+ {"brain", 1340},
+ {"heart", 290},
+ {"liver", 1494},
+ {"pancreas", 131},
+ {"prostate", 62},
+ {"spleen", 162},
+ }
+
+ sort.Sort(ByWeight{s})
+ fmt.Println("Organs by weight:")
+ printOrgans(s)
+
+ sort.Sort(ByName{s})
+ fmt.Println("Organs by name:")
+ printOrgans(s)
+
+ // Output:
+ // Organs by weight:
+ // prostate (62g)
+ // pancreas (131g)
+ // spleen (162g)
+ // heart (290g)
+ // brain (1340g)
+ // liver (1494g)
+ // Organs by name:
+ // brain (1340g)
+ // heart (290g)
+ // liver (1494g)
+ // pancreas (131g)
+ // prostate (62g)
+ // spleen (162g)
+}
+
+func printOrgans(s []*Organ) {
+ for _, o := range s {
+ fmt.Printf("%-8s (%v)\n", o.Name, o.Weight)
+ }
+}
