Imported Upstream version 2012.01.27upstream-weekly/2012.01.27

1 files changed, 208 insertions, 0 deletions

diff --git a/doc/progs/go1.go b/doc/progs/go1.go
new file mode 100644
index 000000000..0348aa315
--- /dev/null
+++ b/doc/progs/go1.go
@@ -0,0 +1,208 @@
+// 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.
+
+// This file contains examples to embed in the Go 1 release notes document.
+
+package main
+
+import (
+	"errors"
+	"flag"
+	"fmt"
+	"log"
+	"testing"
+	"time"
+	"unicode"
+)
+
+func main() {
+	flag.Parse()
+	stringAppend()
+	mapDelete()
+	mapIteration()
+	multipleAssignment()
+	structEquality()
+	compositeLiterals()
+	runeType()
+	errorExample()
+	timePackage()
+}
+
+var timeout = flag.Duration("timeout", 30*time.Second, "how long to wait for completion")
+
+func mapDelete() {
+	m := map[string]int{"7": 7, "23": 23}
+	k := "7"
+	delete(m, k)
+	if m["7"] != 0 || m["23"] != 23 {
+		log.Fatal("mapDelete:", m)
+	}
+}
+
+func stringAppend() {
+	greeting := []byte{}
+	greeting = append(greeting, []byte("hello ")...)
+	greeting = append(greeting, "world"...)
+	if string(greeting) != "hello world" {
+		log.Fatal("stringAppend: ", string(greeting))
+	}
+}
+
+func mapIteration() {
+	m := map[string]int{"Sunday": 0, "Monday": 1}
+	for name, value := range m {
+		// This loop should not assume Sunday will be visited first.
+		f(name, value)
+	}
+}
+
+func f(string, int) {
+}
+
+func assert(t bool) {
+	if !t {
+		log.Panic("assertion fail")
+	}
+}
+
+func multipleAssignment() {
+	sa := []int{1, 2, 3}
+	i := 0
+	i, sa[i] = 1, 2 // sets i = 1, sa[0] = 2
+
+	sb := []int{1, 2, 3}
+	j := 0
+	sb[j], j = 2, 1 // sets sb[0] = 2, j = 1
+
+	sc := []int{1, 2, 3}
+	sc[0], sc[0] = 1, 2 // sets sc[0] = 1, then sc[0] = 2 (so sc[0] = 2 at end)
+
+	assert(i == 1 && sa[0] == 2)
+	assert(j == 1 && sb[0] == 2)
+	assert(sc[0] == 2)
+}
+
+func structEquality() {
+	type Day struct {
+		long  string
+		short string
+	}
+	Christmas := Day{"Christmas", "XMas"}
+	Thanksgiving := Day{"Thanksgiving", "Turkey"}
+	holiday := map[Day]bool{
+		Christmas:    true,
+		Thanksgiving: true,
+	}
+	fmt.Printf("Christmas is a holiday: %t\n", holiday[Christmas])
+}
+
+func compositeLiterals() {
+	type Date struct {
+		month string
+		day   int
+	}
+	// Struct values, fully qualified; always legal.
+	holiday1 := []Date{
+		Date{"Feb", 14},
+		Date{"Nov", 11},
+		Date{"Dec", 25},
+	}
+	// Struct values, type name elided; always legal.
+	holiday2 := []Date{
+		{"Feb", 14},
+		{"Nov", 11},
+		{"Dec", 25},
+	}
+	// Pointers, fully qualified, always legal.
+	holiday3 := []*Date{
+		&Date{"Feb", 14},
+		&Date{"Nov", 11},
+		&Date{"Dec", 25},
+	}
+	// Pointers, type name elided; legal in Go 1.
+	holiday4 := []*Date{
+		{"Feb", 14},
+		{"Nov", 11},
+		{"Dec", 25},
+	}
+	// STOP OMIT
+	_, _, _, _ = holiday1, holiday2, holiday3, holiday4
+}
+
+func runeType() {
+	// STARTRUNE OMIT
+	delta := 'δ' // delta has type rune.
+	var DELTA rune
+	DELTA = unicode.ToUpper(delta)
+	epsilon := unicode.ToLower(DELTA + 1)
+	if epsilon != 'δ'+1 {
+		log.Fatal("inconsistent casing for Greek")
+	}
+	// ENDRUNE OMIT
+}
+
+// START ERROR EXAMPLE OMIT
+type SyntaxError struct {
+	File    string
+	Line    int
+	Message string
+}
+
+func (se *SyntaxError) Error() string {
+	return fmt.Sprintf("%s:%d: %s", se.File, se.Line, se.Message)
+}
+
+// END ERROR EXAMPLE OMIT
+
+func errorExample() {
+	var ErrSyntax = errors.New("syntax error")
+	_ = ErrSyntax
+	se := &SyntaxError{"file", 7, "error"}
+	got := fmt.Sprint(se)
+	const expect = "file:7: error"
+	if got != expect {
+		log.Fatalf("errorsPackage: expected %q got %q", expect, got)
+	}
+}
+
+// sleepUntil sleeps until the specified time. It returns immediately if it's too late.
+func sleepUntil(wakeup time.Time) {
+	now := time.Now() // A Time.
+	if !wakeup.After(now) {
+		return
+	}
+	delta := wakeup.Sub(now) // A Duration.
+	log.Printf("Sleeping for %.3fs", delta.Seconds())
+	time.Sleep(delta)
+}
+
+func timePackage() {
+	sleepUntil(time.Now().Add(123 * time.Millisecond))
+}
+
+func initializationFunction(c chan int) {
+	c <- 1
+}
+
+var PackageGlobal int
+
+func init() {
+	c := make(chan int)
+	go initializationFunction(c)
+	PackageGlobal = <-c
+}
+
+func BenchmarkSprintf(b *testing.B) {
+	// Verify correctness before running benchmark.
+	b.StopTimer()
+	got := fmt.Sprintf("%x", 23)
+	const expect = "17"
+	if expect != got {
+		b.Fatalf("expected %q; got %q", expect, got)
+	}
+	b.StartTimer()
+	for i := 0; i < b.N; i++ {
+		fmt.Sprintf("%x", 23)
+	}
+}