18 files changed, 869 insertions, 0 deletions
diff --git a/doc/progs/cat.go b/doc/progs/cat.go
new file mode 100644
index 000000000..9f0b8d4a3
--- /dev/null
+++ b/doc/progs/cat.go
@@ -0,0 +1,47 @@
+// Copyright 2009 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 (
+	"./file"
+	"flag"
+	"fmt"
+	"os"
+)
+
+func cat(f *file.File) {
+	const NBUF = 512
+	var buf [NBUF]byte
+	for {
+		switch nr, er := f.Read(buf[:]); true {
+		case nr < 0:
+			fmt.Fprintf(os.Stderr, "cat: error reading from %s: %s\n", f.String(), er.String())
+			os.Exit(1)
+		case nr == 0: // EOF
+			return
+		case nr > 0:
+			if nw, ew := file.Stdout.Write(buf[0:nr]); nw != nr {
+				fmt.Fprintf(os.Stderr, "cat: error writing from %s: %s\n", f.String(), ew.String())
+				os.Exit(1)
+			}
+		}
+	}
+}
+
+func main() {
+	flag.Parse() // Scans the arg list and sets up flags
+	if flag.NArg() == 0 {
+		cat(file.Stdin)
+	}
+	for i := 0; i < flag.NArg(); i++ {
+		f, err := file.Open(flag.Arg(i))
+		if f == nil {
+			fmt.Fprintf(os.Stderr, "cat: can't open %s: error %s\n", flag.Arg(i), err)
+			os.Exit(1)
+		}
+		cat(f)
+		f.Close()
+	}
+}
diff --git a/doc/progs/cat_rot13.go b/doc/progs/cat_rot13.go
new file mode 100644
index 000000000..0eefe7cfc
--- /dev/null
+++ b/doc/progs/cat_rot13.go
@@ -0,0 +1,90 @@
+// Copyright 2009 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 (
+	"./file"
+	"flag"
+	"fmt"
+	"os"
+)
+
+var rot13Flag = flag.Bool("rot13", false, "rot13 the input")
+
+func rot13(b byte) byte {
+	if 'a' <= b && b <= 'z' {
+		b = 'a' + ((b-'a')+13)%26
+	}
+	if 'A' <= b && b <= 'Z' {
+		b = 'A' + ((b-'A')+13)%26
+	}
+	return b
+}
+
+type reader interface {
+	Read(b []byte) (ret int, err os.Error)
+	String() string
+}
+
+type rotate13 struct {
+	source reader
+}
+
+func newRotate13(source reader) *rotate13 {
+	return &rotate13{source}
+}
+
+func (r13 *rotate13) Read(b []byte) (ret int, err os.Error) {
+	r, e := r13.source.Read(b)
+	for i := 0; i < r; i++ {
+		b[i] = rot13(b[i])
+	}
+	return r, e
+}
+
+func (r13 *rotate13) String() string {
+	return r13.source.String()
+}
+// end of rotate13 implementation
+
+func cat(r reader) {
+	const NBUF = 512
+	var buf [NBUF]byte
+
+	if *rot13Flag {
+		r = newRotate13(r)
+	}
+	for {
+		switch nr, er := r.Read(buf[:]); {
+		case nr < 0:
+			fmt.Fprintf(os.Stderr, "cat: error reading from %s: %s\n", r.String(), er.String())
+			os.Exit(1)
+		case nr == 0: // EOF
+			return
+		case nr > 0:
+			nw, ew := file.Stdout.Write(buf[0:nr])
+			if nw != nr {
+				fmt.Fprintf(os.Stderr, "cat: error writing from %s: %s\n", r.String(), ew.String())
+				os.Exit(1)
+			}
+		}
+	}
+}
+
+func main() {
+	flag.Parse() // Scans the arg list and sets up flags
+	if flag.NArg() == 0 {
+		cat(file.Stdin)
+	}
+	for i := 0; i < flag.NArg(); i++ {
+		f, err := file.Open(flag.Arg(i))
+		if f == nil {
+			fmt.Fprintf(os.Stderr, "cat: can't open %s: error %s\n", flag.Arg(i), err)
+			os.Exit(1)
+		}
+		cat(f)
+		f.Close()
+	}
+}
diff --git a/doc/progs/echo.go b/doc/progs/echo.go
new file mode 100644
index 000000000..3260edd74
--- /dev/null
+++ b/doc/progs/echo.go
@@ -0,0 +1,32 @@
+// Copyright 2009 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 (
+	"os"
+	"flag" // command line option parser
+)
+
+var omitNewline = flag.Bool("n", false, "don't print final newline")
+
+const (
+	Space   = " "
+	Newline = "\n"
+)
+
+func main() {
+	flag.Parse() // Scans the arg list and sets up flags
+	var s string = ""
+	for i := 0; i < flag.NArg(); i++ {
+		if i > 0 {
+			s += Space
+		}
+		s += flag.Arg(i)
+	}
+	if !*omitNewline {
+		s += Newline
+	}
+	os.Stdout.WriteString(s)
+}
diff --git a/doc/progs/file.go b/doc/progs/file.go
new file mode 100644
index 000000000..2875ce73a
--- /dev/null
+++ b/doc/progs/file.go
@@ -0,0 +1,89 @@
+// Copyright 2009 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 file
+
+import (
+	"os"
+	"syscall"
+)
+
+type File struct {
+	fd   int    // file descriptor number
+	name string // file name at Open time
+}
+
+func newFile(fd int, name string) *File {
+	if fd < 0 {
+		return nil
+	}
+	return &File{fd, name}
+}
+
+var (
+	Stdin  = newFile(syscall.Stdin, "/dev/stdin")
+	Stdout = newFile(syscall.Stdout, "/dev/stdout")
+	Stderr = newFile(syscall.Stderr, "/dev/stderr")
+)
+
+func OpenFile(name string, mode int, perm uint32) (file *File, err os.Error) {
+	r, e := syscall.Open(name, mode, perm)
+	if e != 0 {
+		err = os.Errno(e)
+	}
+	return newFile(r, name), err
+}
+
+const (
+	O_RDONLY = syscall.O_RDONLY
+	O_RDWR   = syscall.O_RDWR
+	O_CREATE = syscall.O_CREAT
+	O_TRUNC  = syscall.O_TRUNC
+)
+
+func Open(name string) (file *File, err os.Error) {
+	return OpenFile(name, O_RDONLY, 0)
+}
+
+func Create(name string) (file *File, err os.Error) {
+	return OpenFile(name, O_RDWR|O_CREATE|O_TRUNC, 0666)
+}
+
+func (file *File) Close() os.Error {
+	if file == nil {
+		return os.EINVAL
+	}
+	e := syscall.Close(file.fd)
+	file.fd = -1 // so it can't be closed again
+	if e != 0 {
+		return os.Errno(e)
+	}
+	return nil
+}
+
+func (file *File) Read(b []byte) (ret int, err os.Error) {
+	if file == nil {
+		return -1, os.EINVAL
+	}
+	r, e := syscall.Read(file.fd, b)
+	if e != 0 {
+		err = os.Errno(e)
+	}
+	return int(r), err
+}
+
+func (file *File) Write(b []byte) (ret int, err os.Error) {
+	if file == nil {
+		return -1, os.EINVAL
+	}
+	r, e := syscall.Write(file.fd, b)
+	if e != 0 {
+		err = os.Errno(e)
+	}
+	return int(r), err
+}
+
+func (file *File) String() string {
+	return file.name
+}
diff --git a/doc/progs/file_windows.go b/doc/progs/file_windows.go
new file mode 100644
index 000000000..03003a3f7
--- /dev/null
+++ b/doc/progs/file_windows.go
@@ -0,0 +1,89 @@
+// Copyright 2009 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 file
+
+import (
+	"os"
+	"syscall"
+)
+
+type File struct {
+	fd   syscall.Handle // file descriptor number
+	name string         // file name at Open time
+}
+
+func newFile(fd syscall.Handle, name string) *File {
+	if fd < 0 {
+		return nil
+	}
+	return &File{fd, name}
+}
+
+var (
+	Stdin  = newFile(syscall.Stdin, "/dev/stdin")
+	Stdout = newFile(syscall.Stdout, "/dev/stdout")
+	Stderr = newFile(syscall.Stderr, "/dev/stderr")
+)
+
+func OpenFile(name string, mode int, perm uint32) (file *File, err os.Error) {
+	r, e := syscall.Open(name, mode, perm)
+	if e != 0 {
+		err = os.Errno(e)
+	}
+	return newFile(r, name), err
+}
+
+const (
+	O_RDONLY = syscall.O_RDONLY
+	O_RDWR   = syscall.O_RDWR
+	O_CREATE = syscall.O_CREAT
+	O_TRUNC  = syscall.O_TRUNC
+)
+
+func Open(name string) (file *File, err os.Error) {
+	return OpenFile(name, O_RDONLY, 0)
+}
+
+func Create(name string) (file *File, err os.Error) {
+	return OpenFile(name, O_RDWR|O_CREATE|O_TRUNC, 0666)
+}
+
+func (file *File) Close() os.Error {
+	if file == nil {
+		return os.EINVAL
+	}
+	e := syscall.Close(file.fd)
+	file.fd = syscall.InvalidHandle // so it can't be closed again
+	if e != 0 {
+		return os.Errno(e)
+	}
+	return nil
+}
+
+func (file *File) Read(b []byte) (ret int, err os.Error) {
+	if file == nil {
+		return -1, os.EINVAL
+	}
+	r, e := syscall.Read(file.fd, b)
+	if e != 0 {
+		err = os.Errno(e)
+	}
+	return int(r), err
+}
+
+func (file *File) Write(b []byte) (ret int, err os.Error) {
+	if file == nil {
+		return -1, os.EINVAL
+	}
+	r, e := syscall.Write(file.fd, b)
+	if e != 0 {
+		err = os.Errno(e)
+	}
+	return int(r), err
+}
+
+func (file *File) String() string {
+	return file.name
+}
diff --git a/doc/progs/helloworld.go b/doc/progs/helloworld.go
new file mode 100644
index 000000000..8185038d9
--- /dev/null
+++ b/doc/progs/helloworld.go
@@ -0,0 +1,11 @@
+// Copyright 2009 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 "fmt" // Package implementing formatted I/O.
+
+func main() {
+	fmt.Printf("Hello, world; or Καλημέρα κόσμε; or こんにちは 世界\n")
+}
diff --git a/doc/progs/helloworld3.go b/doc/progs/helloworld3.go
new file mode 100644
index 000000000..2011513b7
--- /dev/null
+++ b/doc/progs/helloworld3.go
@@ -0,0 +1,21 @@
+// Copyright 2009 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 (
+	"./file"
+	"fmt"
+	"os"
+)
+
+func main() {
+	hello := []byte("hello, world\n")
+	file.Stdout.Write(hello)
+	f, err := file.Open("/does/not/exist")
+	if f == nil {
+		fmt.Printf("can't open file; err=%s\n", err.String())
+		os.Exit(1)
+	}
+}
diff --git a/doc/progs/print.go b/doc/progs/print.go
new file mode 100644
index 000000000..8f44ba8c6
--- /dev/null
+++ b/doc/progs/print.go
@@ -0,0 +1,23 @@
+// Copyright 2009 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"
+
+func main() {
+	var u64 uint64 = 1<<64 - 1
+	fmt.Printf("%d %d\n", u64, int64(u64))
+
+	// harder stuff
+	type T struct {
+		a int
+		b string
+	}
+	t := T{77, "Sunset Strip"}
+	a := []int{1, 2, 3, 4}
+	fmt.Printf("%v %v %v\n", u64, t, a)
+	fmt.Print(u64, " ", t, " ", a, "\n")
+	fmt.Println(u64, t, a)
+}
diff --git a/doc/progs/print_string.go b/doc/progs/print_string.go
new file mode 100644
index 000000000..46ab1d91a
--- /dev/null
+++ b/doc/progs/print_string.go
@@ -0,0 +1,21 @@
+// Copyright 2009 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"
+
+type testType struct {
+	a int
+	b string
+}
+
+func (t *testType) String() string {
+	return fmt.Sprint(t.a) + " " + t.b
+}
+
+func main() {
+	t := &testType{77, "Sunset Strip"}
+	fmt.Println(t)
+}
diff --git a/doc/progs/run b/doc/progs/run
new file mode 100755
index 000000000..81781c9d2
--- /dev/null
+++ b/doc/progs/run
@@ -0,0 +1,85 @@
+#!/usr/bin/env bash
+# Copyright 2009 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.
+
+set -e
+
+eval $(gomake --no-print-directory -f ../../src/Make.inc go-env)
+
+if [ -z "$O" ]; then
+	echo 'missing $O - maybe no Make.$GOARCH?' 1>&2
+	exit 1
+fi
+
+rm -f *.$O
+
+if [ "$GOOS" = "windows" ];then
+	$GC -o file.8 file_windows.go
+else
+	$GC file.go
+fi
+
+for i in \
+	helloworld.go \
+	helloworld3.go \
+	echo.go \
+	cat.go \
+	cat_rot13.go \
+	sum.go \
+	sort.go \
+	sortmain.go \
+	print.go \
+	print_string.go \
+	sieve.go \
+	sieve1.go \
+	server1.go \
+	strings.go \
+; do
+	$GC $i
+done
+
+function testit {
+	$LD $1.$O
+	x=$(echo $(./$O.out $2 2>&1))  # extra echo canonicalizes
+	if [ "$x" != "$3" ]
+	then
+		echo $1 failed: '"'$x'"' is not '"'$3'"'
+	fi
+}
+
+function testitpipe {
+	$LD $1.$O
+	x=$(echo $(./$O.out | $2 2>&1))  # extra echo canonicalizes
+	if [ "$x" != "$3" ]
+	then
+		echo $1 failed: '"'$x'"' is not '"'$3'"'
+	fi
+}
+
+
+testit helloworld "" "Hello, world; or Καλημέρα κόσμε; or こんにちは 世界"
+testit helloworld3 "" "hello, world can't open file; err=no such file or directory"
+testit echo "hello, world" "hello, world"
+testit sum "" "6"
+testit strings "" ""
+
+alphabet=abcdefghijklmnopqrstuvwxyz
+rot13=nopqrstuvwxyzabcdefghijklm
+echo $alphabet | testit cat "" $alphabet
+echo $alphabet | testit cat_rot13 "--rot13" $rot13
+echo $rot13 | testit cat_rot13 "--rot13" $alphabet
+
+testit sortmain "" "Sunday Monday Tuesday Wednesday Thursday Friday Saturday"
+
+testit print "" "18446744073709551615 -1 18446744073709551615 {77 Sunset Strip} [1 2 3 4] 18446744073709551615 {77 Sunset Strip} [1 2 3 4] 18446744073709551615 {77 Sunset Strip} [1 2 3 4]"
+testit print_string "" "77 Sunset Strip"
+
+testitpipe sieve "sed 10q" "2 3 5 7 11 13 17 19 23 29"
+testitpipe sieve "sed 10q" "2 3 5 7 11 13 17 19 23 29"
+
+# server hangs; don't run it, just compile it
+$GC server.go
+testit server1 "" ""
+
+rm -f $O.out *.$O
diff --git a/doc/progs/server.go b/doc/progs/server.go
new file mode 100644
index 000000000..b498b53a6
--- /dev/null
+++ b/doc/progs/server.go
@@ -0,0 +1,51 @@
+// Copyright 2009 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"
+
+type request struct {
+	a, b   int
+	replyc chan int
+}
+
+type binOp func(a, b int) int
+
+func run(op binOp, req *request) {
+	reply := op(req.a, req.b)
+	req.replyc <- reply
+}
+
+func server(op binOp, service chan *request) {
+	for {
+		req := <-service
+		go run(op, req) // don't wait for it
+	}
+}
+
+func startServer(op binOp) chan *request {
+	req := make(chan *request)
+	go server(op, req)
+	return req
+}
+
+func main() {
+	adder := startServer(func(a, b int) int { return a + b })
+	const N = 100
+	var reqs [N]request
+	for i := 0; i < N; i++ {
+		req := &reqs[i]
+		req.a = i
+		req.b = i + N
+		req.replyc = make(chan int)
+		adder <- req
+	}
+	for i := N - 1; i >= 0; i-- { // doesn't matter what order
+		if <-reqs[i].replyc != N+2*i {
+			fmt.Println("fail at", i)
+		}
+	}
+	fmt.Println("done")
+}
diff --git a/doc/progs/server1.go b/doc/progs/server1.go
new file mode 100644
index 000000000..a4093924b
--- /dev/null
+++ b/doc/progs/server1.go
@@ -0,0 +1,56 @@
+// Copyright 2009 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"
+
+type request struct {
+	a, b   int
+	replyc chan int
+}
+
+type binOp func(a, b int) int
+
+func run(op binOp, req *request) {
+	reply := op(req.a, req.b)
+	req.replyc <- reply
+}
+
+func server(op binOp, service chan *request, quit chan bool) {
+	for {
+		select {
+		case req := <-service:
+			go run(op, req) // don't wait for it
+		case <-quit:
+			return
+		}
+	}
+}
+
+func startServer(op binOp) (service chan *request, quit chan bool) {
+	service = make(chan *request)
+	quit = make(chan bool)
+	go server(op, service, quit)
+	return service, quit
+}
+
+func main() {
+	adder, quit := startServer(func(a, b int) int { return a + b })
+	const N = 100
+	var reqs [N]request
+	for i := 0; i < N; i++ {
+		req := &reqs[i]
+		req.a = i
+		req.b = i + N
+		req.replyc = make(chan int)
+		adder <- req
+	}
+	for i := N - 1; i >= 0; i-- { // doesn't matter what order
+		if <-reqs[i].replyc != N+2*i {
+			fmt.Println("fail at", i)
+		}
+	}
+	quit <- true
+}
diff --git a/doc/progs/sieve.go b/doc/progs/sieve.go
new file mode 100644
index 000000000..b31530981
--- /dev/null
+++ b/doc/progs/sieve.go
@@ -0,0 +1,38 @@
+// Copyright 2009 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"
+
+// Send the sequence 2, 3, 4, ... to channel 'ch'.
+func generate(ch chan int) {
+	for i := 2; ; i++ {
+		ch <- i // Send 'i' to channel 'ch'.
+	}
+}
+
+// Copy the values from channel 'in' to channel 'out',
+// removing those divisible by 'prime'.
+func filter(in, out chan int, prime int) {
+	for {
+		i := <-in // Receive value of new variable 'i' from 'in'.
+		if i%prime != 0 {
+			out <- i // Send 'i' to channel 'out'.
+		}
+	}
+}
+
+// The prime sieve: Daisy-chain filter processes together.
+func main() {
+	ch := make(chan int)       // Create a new channel.
+	go generate(ch)            // Start generate() as a goroutine.
+	for i := 0; i < 100; i++ { // Print the first hundred primes.
+		prime := <-ch
+		fmt.Println(prime)
+		ch1 := make(chan int)
+		go filter(ch, ch1, prime)
+		ch = ch1
+	}
+}
diff --git a/doc/progs/sieve1.go b/doc/progs/sieve1.go
new file mode 100644
index 000000000..e1411a334
--- /dev/null
+++ b/doc/progs/sieve1.go
@@ -0,0 +1,51 @@
+// Copyright 2009 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"
+
+// Send the sequence 2, 3, 4, ... to returned channel 
+func generate() chan int {
+	ch := make(chan int)
+	go func() {
+		for i := 2; ; i++ {
+			ch <- i
+		}
+	}()
+	return ch
+}
+
+// Filter out input values divisible by 'prime', send rest to returned channel
+func filter(in chan int, prime int) chan int {
+	out := make(chan int)
+	go func() {
+		for {
+			if i := <-in; i%prime != 0 {
+				out <- i
+			}
+		}
+	}()
+	return out
+}
+
+func sieve() chan int {
+	out := make(chan int)
+	go func() {
+		ch := generate()
+		for {
+			prime := <-ch
+			out <- prime
+			ch = filter(ch, prime)
+		}
+	}()
+	return out
+}
+
+func main() {
+	primes := sieve()
+	for i := 0; i < 100; i++ { // Print the first hundred primes.
+		fmt.Println(<-primes)
+	}
+}
diff --git a/doc/progs/sort.go b/doc/progs/sort.go
new file mode 100644
index 000000000..894693f0d
--- /dev/null
+++ b/doc/progs/sort.go
@@ -0,0 +1,59 @@
+// Copyright 2009 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
+
+type Interface interface {
+	Len() int
+	Less(i, j int) bool
+	Swap(i, j int)
+}
+
+func Sort(data Interface) {
+	for i := 1; i < data.Len(); i++ {
+		for j := i; j > 0 && data.Less(j, j-1); j-- {
+			data.Swap(j, j-1)
+		}
+	}
+}
+
+func IsSorted(data Interface) bool {
+	n := data.Len()
+	for i := n - 1; i > 0; i-- {
+		if data.Less(i, i-1) {
+			return false
+		}
+	}
+	return true
+}
+
+// Convenience types for common cases
+
+type IntSlice []int
+
+func (p IntSlice) Len() int           { return len(p) }
+func (p IntSlice) Less(i, j int) bool { return p[i] < p[j] }
+func (p IntSlice) Swap(i, j int)      { p[i], p[j] = p[j], p[i] }
+
+type Float64Slice []float64
+
+func (p Float64Slice) Len() int           { return len(p) }
+func (p Float64Slice) Less(i, j int) bool { return p[i] < p[j] }
+func (p Float64Slice) Swap(i, j int)      { p[i], p[j] = p[j], p[i] }
+
+type StringSlice []string
+
+func (p StringSlice) Len() int           { return len(p) }
+func (p StringSlice) Less(i, j int) bool { return p[i] < p[j] }
+func (p StringSlice) Swap(i, j int)      { p[i], p[j] = p[j], p[i] }
+
+// Convenience wrappers for common cases
+
+func SortInts(a []int)         { Sort(IntSlice(a)) }
+func SortFloat64s(a []float64) { Sort(Float64Slice(a)) }
+func SortStrings(a []string)   { Sort(StringSlice(a)) }
+
+func IntsAreSorted(a []int) bool         { return IsSorted(IntSlice(a)) }
+func Float64sAreSorted(a []float64) bool { return IsSorted(Float64Slice(a)) }
+func StringsAreSorted(a []string) bool   { return IsSorted(StringSlice(a)) }
diff --git a/doc/progs/sortmain.go b/doc/progs/sortmain.go
new file mode 100644
index 000000000..c1babb01f
--- /dev/null
+++ b/doc/progs/sortmain.go
@@ -0,0 +1,69 @@
+// Copyright 2009 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"
+	"./sort"
+)
+
+func ints() {
+	data := []int{74, 59, 238, -784, 9845, 959, 905, 0, 0, 42, 7586, -5467984, 7586}
+	a := sort.IntSlice(data)
+	sort.Sort(a)
+	if !sort.IsSorted(a) {
+		panic("fail")
+	}
+}
+
+func strings() {
+	data := []string{"monday", "tuesday", "wednesday", "thursday", "friday", "saturday", "sunday"}
+	a := sort.StringSlice(data)
+	sort.Sort(a)
+	if !sort.IsSorted(a) {
+		panic("fail")
+	}
+}
+
+type day struct {
+	num       int
+	shortName string
+	longName  string
+}
+
+type dayArray struct {
+	data []*day
+}
+
+func (p *dayArray) Len() int           { return len(p.data) }
+func (p *dayArray) Less(i, j int) bool { return p.data[i].num < p.data[j].num }
+func (p *dayArray) Swap(i, j int)      { p.data[i], p.data[j] = p.data[j], p.data[i] }
+
+func days() {
+	Sunday := day{0, "SUN", "Sunday"}
+	Monday := day{1, "MON", "Monday"}
+	Tuesday := day{2, "TUE", "Tuesday"}
+	Wednesday := day{3, "WED", "Wednesday"}
+	Thursday := day{4, "THU", "Thursday"}
+	Friday := day{5, "FRI", "Friday"}
+	Saturday := day{6, "SAT", "Saturday"}
+	data := []*day{&Tuesday, &Thursday, &Wednesday, &Sunday, &Monday, &Friday, &Saturday}
+	a := dayArray{data}
+	sort.Sort(&a)
+	if !sort.IsSorted(&a) {
+		panic("fail")
+	}
+	for _, d := range data {
+		fmt.Printf("%s ", d.longName)
+	}
+	fmt.Printf("\n")
+}
+
+
+func main() {
+	ints()
+	strings()
+	days()
+}
diff --git a/doc/progs/strings.go b/doc/progs/strings.go
new file mode 100644
index 000000000..e6739b385
--- /dev/null
+++ b/doc/progs/strings.go
@@ -0,0 +1,17 @@
+// Copyright 2009 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 "os"
+
+func main() {
+	s := "hello"
+	if s[1] != 'e' {
+		os.Exit(1)
+	}
+	s = "good bye"
+	var p *string = &s
+	*p = "ciao"
+}
diff --git a/doc/progs/sum.go b/doc/progs/sum.go
new file mode 100644
index 000000000..e022195ed
--- /dev/null
+++ b/doc/progs/sum.go
@@ -0,0 +1,20 @@
+// Copyright 2009 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"
+
+func sum(a []int) int { // returns an int
+	s := 0
+	for i := 0; i < len(a); i++ {
+		s += a[i]
+	}
+	return s
+}
+
+func main() {
+	s := sum([3]int{1, 2, 3}[:]) // a slice of the array is passed to sum
+	fmt.Print(s, "\n")
+}