From 49870a97015de0242cceee04459172868eec2524 Mon Sep 17 00:00:00 2001 From: Mark McGranaghan Date: Sun, 6 Oct 2013 09:25:48 -0700 Subject: [PATCH] place gopher run link in top-right of rendered go source --- public/arrays | 12 ++++++++++- public/atomic-counters | 13 +++++++++++- public/base64-encoding | 11 +++++++++- public/channel-buffering | 9 +++++++- public/channel-directions | 8 ++++++- public/channel-synchronization | 11 +++++++++- public/channels | 10 ++++++++- public/closing-channels | 10 ++++++++- public/closures | 11 +++++++++- public/collection-functions | 22 ++++++++++++++++++- public/command-line-arguments | 10 ++++++++- public/command-line-flags | 18 +++++++++++++++- public/constants | 11 +++++++++- public/defer | 11 +++++++++- public/environment-variables | 10 ++++++++- public/epoch | 10 ++++++++- public/errors | 17 ++++++++++++++- public/execing-processes | 11 +++++++++- public/exit | 11 +++++++++- public/for | 10 ++++++++- public/functions | 10 ++++++++- public/goroutines | 12 ++++++++++- public/hello-world | 8 ++++++- public/if-else | 11 +++++++++- public/interfaces | 13 +++++++++++- public/json | 23 +++++++++++++++++++- public/line-filters | 12 ++++++++++- public/maps | 14 ++++++++++++- public/methods | 12 ++++++++++- public/multiple-return-values | 10 ++++++++- public/mutexes | 17 ++++++++++++++- public/non-blocking-channel-operations | 9 +++++++- public/number-parsing | 13 +++++++++++- public/panic | 10 ++++++++- public/pointers | 11 +++++++++- public/random-numbers | 13 +++++++++++- public/range | 10 ++++++++- public/range-over-channels | 9 +++++++- public/rate-limiting | 14 ++++++++++++- public/reading-files | 17 ++++++++++++++- public/recursion | 7 ++++++- public/regular-expressions | 21 ++++++++++++++++++- public/select | 10 ++++++++- public/sha1-hashes | 12 ++++++++++- public/signals | 10 ++++++++- public/slices | 18 +++++++++++++++- public/sorting | 9 +++++++- public/sorting-by-functions | 9 +++++++- public/spawning-processes | 14 ++++++++++++- public/stateful-goroutines | 16 +++++++++++++- public/string-formatting | 29 +++++++++++++++++++++++++- public/string-functions | 11 +++++++++- public/structs | 14 ++++++++++++- public/switch | 9 +++++++- public/tickers | 8 ++++++- public/time | 15 ++++++++++++- public/time-formatting-parsing | 12 ++++++++++- public/timeouts | 10 ++++++++- public/timers | 9 +++++++- public/url-parsing | 13 +++++++++++- public/values | 9 +++++++- public/variables | 11 +++++++++- public/variadic-functions | 10 ++++++++- public/worker-pools | 12 ++++++++++- public/writing-files | 18 +++++++++++++++- templates/example.tmpl | 2 +- tools/generate.go | 7 ++++--- 67 files changed, 740 insertions(+), 69 deletions(-) diff --git a/public/arrays b/public/arrays index 97cc19e..14b3c44 100644 --- a/public/arrays +++ b/public/arrays @@ -20,7 +20,6 @@

Go by Example: Arrays

- @@ -31,6 +30,7 @@ specific length.

@@ -40,6 +40,7 @@ specific length.

diff --git a/public/atomic-counters b/public/atomic-counters index 9049976..174cc61 100644 --- a/public/atomic-counters +++ b/public/atomic-counters @@ -20,7 +20,6 @@

Go by Example: Atomic Counters

-
+
+ 
package main
@@ -51,6 +52,7 @@ specific length.

 + 
import "fmt"
@@ -62,6 +64,7 @@ specific length.

 + 
func main() {
@@ -77,6 +80,7 @@ zero-valued, which for ints means 0s.

 + 
    var a [5]int
     fmt.Println("emp:", a)
@@ -92,6 +96,7 @@ zero-valued, which for ints means 0s.

 + 
    a[4] = 100
     fmt.Println("set:", a)
     fmt.Println("get:", a[4])
@@ -106,6 +111,7 @@ zero-valued, which for ints means 0s.
+ 
    fmt.Println("len:", len(a))
@@ -119,6 +125,7 @@ in one line.

 + 
    b := [5]int{1, 2, 3, 4, 5}
     fmt.Println("dcl:", b)
@@ -134,6 +141,7 @@ structures.

 + 
    var twoD [2][3]int
     for i := 0; i < 2; i++ {
         for j := 0; j < 3; j++ {
@@ -158,6 +166,7 @@ when printed with fmt.Println.
+ 
$ go run arrays.go
 emp: [0 0 0 0 0]
 set: [0 0 0 0 100]
@@ -177,6 +186,7 @@ typical Go. We’ll look at slices next.
+
@@ -35,6 +34,7 @@ counters accessed by multiple goroutines.

@@ -44,6 +44,7 @@ counters accessed by multiple goroutines.

diff --git a/public/base64-encoding b/public/base64-encoding index 0a565dc..0d07525 100644 --- a/public/base64-encoding +++ b/public/base64-encoding @@ -20,7 +20,6 @@

Go by Example: Base64 Encoding

-
+
+ 
package main
@@ -55,6 +56,7 @@ counters accessed by multiple goroutines.

 + 
import "fmt"
 import "time"
 import "sync/atomic"
@@ -69,6 +71,7 @@ counters accessed by multiple goroutines.
+ 
func main() {
@@ -82,6 +85,7 @@ counters accessed by multiple goroutines.

 + 
    var ops uint64 = 0
@@ -96,6 +100,7 @@ once a millisecond.

 + 
    for i := 0; i < 50; i++ {
         go func() {
             for {
@@ -113,6 +118,7 @@ address of our ops counter with the
+ 
                atomic.AddUint64(&ops, 1)
@@ -125,6 +131,7 @@ address of our ops counter with the 		+ 
                runtime.Gosched()
             }
         }()
@@ -140,6 +147,7 @@ address of our ops counter with the
+ 
    time.Sleep(time.Second)
@@ -157,6 +165,7 @@ fetch the value.

 + 
    opsFinal := atomic.LoadUint64(&ops)
     fmt.Println("ops:", opsFinal)
 }
@@ -176,6 +185,7 @@ fetch the value.
+ 
$ go run atomic-counters.go
 ops: 40200
@@ -190,6 +200,7 @@ state.

 +
@@ -31,6 +30,7 @@ encoding/decoding.

@@ -40,6 +40,7 @@ encoding/decoding.

+
+ 
package main
@@ -54,6 +55,7 @@ save us some space below.

 + 
import b64 "encoding/base64"
 import "fmt"
@@ -66,6 +68,7 @@ save us some space below.

 + 
func main() {
@@ -78,6 +81,7 @@ save us some space below.

 + 
    data := "abc123!?$*&()'-=@~"
@@ -93,6 +97,7 @@ cast our string to that type.

 + 
    sEnc := b64.StdEncoding.EncodeToString([]byte(data))
     fmt.Println(sEnc)
@@ -108,6 +113,7 @@ well-formed.

 + 
    sDec, _ := b64.StdEncoding.DecodeString(sEnc)
     fmt.Println(string(sDec))
     fmt.Println()
@@ -123,6 +129,7 @@ format.
+ 
    uEnc := b64.URLEncoding.EncodeToString([]byte(data))
     fmt.Println(uEnc)
     uDec, _ := b64.URLEncoding.DecodeString(uEnc)
@@ -145,6 +152,7 @@ but they both decode to the original string as desired.
+ 
$ go run base64-encoding.go
 YWJjMTIzIT8kKiYoKSctPUB+
 abc123!?$*&()'-=@~
@@ -158,6 +166,7 @@ but they both decode to the original string as desired.
+ 
YWJjMTIzIT8kKiYoKSctPUB-
 abc123!?$*&()'-=@~
diff --git a/public/channel-buffering b/public/channel-buffering index afff1d0..5893c33 100644 --- a/public/channel-buffering +++ b/public/channel-buffering @@ -20,7 +20,6 @@

Go by Example: Channel Buffering

- @@ -35,6 +34,7 @@ those values.

@@ -44,6 +44,7 @@ those values.

+
+ 
package main
@@ -55,6 +56,7 @@ those values.

 + 
import "fmt"
@@ -66,6 +68,7 @@ those values.

 + 
func main() {
@@ -79,6 +82,7 @@ those values.

 + 
    messages := make(chan string, 2)
@@ -93,6 +97,7 @@ concurrent receive.

 + 
    messages <- "buffered"
     messages <- "channel"
@@ -106,6 +111,7 @@ concurrent receive.

 + 
    fmt.Println(<-messages)
     fmt.Println(<-messages)
 }
@@ -123,6 +129,7 @@ concurrent receive.
+ 
$ go run channel-buffering.go 
 buffered
 channel
diff --git a/public/channel-directions b/public/channel-directions
index 6b94688..c1171ae 100644
--- a/public/channel-directions
+++ b/public/channel-directions
@@ -20,7 +20,6 @@
   
     

       
Go by Example: Channel Directions

-      
       
       
         
@@ -33,6 +32,7 @@ the program.

@@ -42,6 +42,7 @@ the program.

 
           
           

+	        
             
           
         

             
           
           

+	        
             
package main
 

 
@@ -53,6 +54,7 @@ the program.

             
           		
           
+	        
             
import "fmt"
 

 
@@ -67,6 +69,7 @@ receive on this channel.

 
           		
           
+	        
             
func ping(pings chan<- string, msg string) {
     pings <- msg
 }
@@ -82,6 +85,7 @@ receive on this channel.

 
           

           
+	        
             
func pong(pings <-chan string, pongs chan<- string) {
     msg := <-pings
     pongs <- msg
@@ -96,6 +100,7 @@ receive on this channel.

             
           

           
+	        
             
func main() {
     pings := make(chan string, 1)
     pongs := make(chan string, 1)
@@ -117,6 +122,7 @@ receive on this channel.

             
           

           
+	        
             
$ go run channel-directions.go
 passed message
 

diff --git a/public/channel-synchronization b/public/channel-synchronization
index 011169f..ed359f3 100644
--- a/public/channel-synchronization
+++ b/public/channel-synchronization
@@ -20,7 +20,6 @@
   
     

       
Go by Example: Channel Synchronization

-      
       
       
         
@@ -32,6 +31,7 @@ blocking receive to wait for a goroutine to finish.

@@ -41,6 +41,7 @@ blocking receive to wait for a goroutine to finish.

diff --git a/public/channels b/public/channels
index 83656f1..fbb9329 100644
--- a/public/channels
+++ b/public/channels
@@ -20,7 +20,6 @@
   

       
Go by Example: Channels

-      
       
       

 
           
           

+	        
             
           
         

             
           
           

+	        
             
package main
 

 
@@ -52,6 +53,7 @@ blocking receive to wait for a goroutine to finish.

             
           		
           
+	        
             
import "fmt"
 import "time"
 

@@ -67,6 +69,7 @@ goroutine that this function’s work is done.

 
           		
           
+	        
             
func worker(done chan bool) {
     fmt.Print("working...")
     time.Sleep(time.Second)
@@ -82,6 +85,7 @@ goroutine that this function’s work is done.

 
           

           
+	        
             
    done <- true
 }
 

@@ -94,6 +98,7 @@ goroutine that this function’s work is done.

             
           		
           
+	        
             
func main() {
 

 
@@ -107,6 +112,7 @@ notify on.

 
           		
           
+	        
             
    done := make(chan bool, 1)
     go worker(done)
 

@@ -121,6 +127,7 @@ worker on the channel.

 
           		
           
+	        
             
    <-done
 }
 

@@ -137,6 +144,7 @@ worker on the channel.

             
           		
           
+	        
             
$ go run channel-synchronization.go      
 working...done                  
 

@@ -152,6 +160,7 @@ started.

 
           		
           
+	        
             
           
         

     

         
@@ -34,6 +33,7 @@ underly much of Go’s functionality.

@@ -43,6 +43,7 @@ underly much of Go’s functionality.

diff --git a/public/closing-channels b/public/closing-channels
index 2a7fa83..c614498 100644
--- a/public/closing-channels
+++ b/public/closing-channels
@@ -20,7 +20,6 @@
   

       
Go by Example: Closing Channels

-      
       
       

 
           
           

+	        
             
           
         

             
           
           

+	        
             
package main
 

 
@@ -54,6 +55,7 @@ underly much of Go’s functionality.

             
           		
           
+	        
             
import "fmt"
 

 
@@ -65,6 +67,7 @@ underly much of Go’s functionality.

             
           		
           
+	        
             
func main() {
 

 
@@ -78,6 +81,7 @@ Channels are typed by the values they convey.

 
           		
           
+	        
             
    messages := make(chan string)
 

 
@@ -92,6 +96,7 @@ channel we made above, from a new goroutine.

 
           		
           
+	        
             
    go func() { messages <- "ping" }()
 

 
@@ -106,6 +111,7 @@ we sent above and print it out.

 
           		
           
+	        
             
    msg := <-messages
     fmt.Println(msg)
 }
@@ -126,6 +132,7 @@ channel.

 
           

           
+	        
             
$ go run channels.go 
 ping
 

@@ -142,6 +149,7 @@ message without having to use any other synchronization.

 
           		
           
+	        
             
           
         

     

         
@@ -32,6 +31,7 @@ completion to the channel’s receivers.

@@ -41,6 +41,7 @@ completion to the channel’s receivers.

diff --git a/public/closures b/public/closures
index 2e1372c..fcc0b6d 100644
--- a/public/closures
+++ b/public/closures
@@ -20,7 +20,6 @@
   

       
Go by Example: Closures

-      
       
       

 
           
           

+	        
             
           
         

             
           
           

+	        
             
package main
 

 
@@ -52,6 +53,7 @@ completion to the channel’s receivers.

             
           		
           
+	        
             
import "fmt"
 

 
@@ -67,6 +69,7 @@ the worker we’ll close the jobs channel.

 
           		
           
+	        
             
func main() {
     jobs := make(chan int, 5)
     done := make(chan bool)
@@ -87,6 +90,7 @@ all our jobs.

 
           

           
+	        
             
    go func() {
         for {
             j, more := <-jobs
@@ -111,6 +115,7 @@ channel, then closes it.

 
           

           
+	        
             
    for j := 1; j <= 3; j++ {
         jobs <- j
         fmt.Println("sent job", j)
@@ -130,6 +135,7 @@ we saw earlier.

 
           

           
+	        
             
    <-done
 }
 

@@ -146,6 +152,7 @@ we saw earlier.

             
           		
           
+	        
             
$ go run closing-channels.go 
 sent job 1
 received job 1
@@ -167,6 +174,7 @@ example: range over channels.

 
           

           
+	        
             
           
         

     

         
@@ -33,6 +32,7 @@ a function inline without having to name it.

@@ -42,6 +42,7 @@ a function inline without having to name it.

diff --git a/public/collection-functions b/public/collection-functions
index c8b070e..e692eb7 100644
--- a/public/collection-functions
+++ b/public/collection-functions
@@ -20,7 +20,6 @@
   

       
Go by Example: Collection Functions

-      
       
       

 
           
           

+	        
             
           
         

             
           
           

+	        
             
package main
 

 
@@ -53,6 +54,7 @@ a function inline without having to name it.

             
           		
           
+	        
             
import "fmt"
 

 
@@ -68,6 +70,7 @@ form a closure.

 
           		
           
+	        
             
func intSeq() func() int {
     i := 0
     return func() int {
@@ -85,6 +88,7 @@ form a closure.

             
           

           
+	        
             
func main() {
 

 
@@ -100,6 +104,7 @@ we call nextInt.

 
           		
           
+	        
             
    nextInt := intSeq()
 

 
@@ -113,6 +118,7 @@ a few times.

 
           		
           
+	        
             
    fmt.Println(nextInt())
     fmt.Println(nextInt())
     fmt.Println(nextInt())
@@ -128,6 +134,7 @@ particular function, create and test a new one.

 
           

           
+	        
             
    newInts := intSeq()
     fmt.Println(newInts())
 }
@@ -145,6 +152,7 @@ particular function, create and test a new one.

             
           

           
+	        
             
$ go run closures.go
 1
 2
@@ -162,6 +170,7 @@ recursion.

 
           

           
+	        
             
           
         

     

         
@@ -33,6 +32,7 @@ collection with a custom function.

@@ -47,6 +47,7 @@ your program and data types.

@@ -62,6 +63,7 @@ helper function.

@@ -71,6 +73,7 @@ helper function.

 
           
           

+	        
             
           
         

 
           
           

+	        
             
           
         

 
           
           

+	        
             
           
         

             
           
           

+	        
             
package main
 

 
@@ -82,6 +85,7 @@ helper function.

             
           		
           
+	        
             
import "strings"
 import "fmt"
 

@@ -96,6 +100,7 @@ helper function.

 
           		
           
+	        
             
func Index(vs []string, t string) int {
     for i, v := range vs {
         if v == t {
@@ -116,6 +121,7 @@ slice.

 
           

           
+	        
             
func Include(vs []string, t string) bool {
     return Index(vs, t) >= 0
 }
@@ -131,6 +137,7 @@ satisfies the predicate f.

 
           

           
+	        
             
func Any(vs []string, f func(string) bool) bool {
     for _, v := range vs {
         if f(v) {
@@ -151,6 +158,7 @@ satisfy the predicate f.

 
           

           
+	        
             
func All(vs []string, f func(string) bool) bool {
     for _, v := range vs {
         if !f(v) {
@@ -171,6 +179,7 @@ slice that satisfy the predicate f.

 
           

           
+	        
             
func Filter(vs []string, f func(string) bool) []string {
     vsf := make([]string, 0)
     for _, v := range vs {
@@ -192,6 +201,7 @@ the function f to each string in the original slice.

 
           

           
+	        
             
func Map(vs []string, f func(string) string) []string {
     vsm := make([]string, len(vs))
     for i, v := range vs {
@@ -209,6 +219,7 @@ the function f to each string in the original slice.

             
           

           
+	        
             
func main() {
 

 
@@ -221,6 +232,7 @@ the function f to each string in the original slice.

 
           		
           
+	        
             
    var strs = []string{"peach", "apple", "pear", "plum"}
 

 
@@ -232,6 +244,7 @@ the function f to each string in the original slice.

             
           		
           
+	        
             
    fmt.Println(Index(strs, "pear"))
 

 
@@ -243,6 +256,7 @@ the function f to each string in the original slice.

             
           		
           
+	        
             
    fmt.Println(Include(strs, "grape"))
 

 
@@ -254,6 +268,7 @@ the function f to each string in the original slice.

             
           		
           
+	        
             
    fmt.Println(Any(strs, func(v string) bool {
         return strings.HasPrefix(v, "p")
     }))
@@ -267,6 +282,7 @@ the function f to each string in the original slice.

             
           

           
+	        
             
    fmt.Println(All(strs, func(v string) bool {
         return strings.HasPrefix(v, "p")
     }))
@@ -280,6 +296,7 @@ the function f to each string in the original slice.

             
           

           
+	        
             
    fmt.Println(Filter(strs, func(v string) bool {
         return strings.Contains(v, "e")
     }))
@@ -296,6 +313,7 @@ type.

 
           

           
+	        
             
    fmt.Println(Map(strs, strings.ToUpper))
 

 
@@ -307,6 +325,7 @@ type.

             
           		
           
+	        
             
}
 

 
@@ -322,6 +341,7 @@ type.

             
           		
           
+	        
             
$ go run collection-functions.go 
 2
 false
diff --git a/public/command-line-arguments b/public/command-line-arguments
index 6d80fed..8067ee8 100644
--- a/public/command-line-arguments
+++ b/public/command-line-arguments
@@ -20,7 +20,6 @@
   
     

       
Go by Example: Command-Line Arguments

-      
       
       
         
@@ -33,6 +32,7 @@ For example, go run hello.go uses run and
 
           
@@ -42,6 +42,7 @@ For example, go run hello.go uses run and
             
           
diff --git a/public/command-line-flags b/public/command-line-flags
index cf2ca8a..6b0bb4b 100644
--- a/public/command-line-flags
+++ b/public/command-line-flags
@@ -20,7 +20,6 @@
   

       
Go by Example: Command-Line Flags

-      
       
       

           

+	        
             
           
         

           

+	        
             
package main
 

 
@@ -53,6 +54,7 @@ For example, go run hello.go uses run and
             
           		
           
+	        
             
import "os"
 import "fmt"
 

@@ -65,6 +67,7 @@ For example, go run hello.go uses run and
             
           		
           
+	        
             
func main() {
 

 
@@ -80,6 +83,7 @@ holds the arguments to the program.

 
           		
           
+	        
             
    argsWithProg := os.Args
     argsWithoutProg := os.Args[1:]
 

@@ -93,6 +97,7 @@ holds the arguments to the program.

 
           		
           
+	        
             
    arg := os.Args[3]
 

 
@@ -104,6 +109,7 @@ holds the arguments to the program.

             
           		
           
+	        
             
    fmt.Println(argsWithProg)
     fmt.Println(argsWithoutProg)
     fmt.Println(arg)
@@ -124,6 +130,7 @@ build a binary with go build first.

 
           

           
+	        
             
$ go build command-line-arguments.go
 $ ./command-line-arguments a b c d
 [./command-line-arguments a b c d]       
@@ -141,6 +148,7 @@ with flags.

 
           

           
+	        
             
           
         

     

         
@@ -33,6 +32,7 @@ command-line flag.

@@ -42,6 +42,7 @@ command-line flag.

diff --git a/public/constants b/public/constants
index 73053dc..f9c1320 100644
--- a/public/constants
+++ b/public/constants
@@ -20,7 +20,6 @@
   

       
Go by Example: Constants

-      
       
       

 
           
           

+	        
             
           
         

             
           
           

+	        
             
package main
 

 
@@ -56,6 +57,7 @@ implement our example command-line program.

 
           		
           
+	        
             
import "flag"
 import "fmt"
 

@@ -68,6 +70,7 @@ implement our example command-line program.

             
           		
           
+	        
             
func main() {
 

 
@@ -85,6 +88,7 @@ we’ll see how to use this pointer below.

 
           		
           
+	        
             
    wordPtr := flag.String("word", "foo", "a string")
 

 
@@ -98,6 +102,7 @@ similar approach to the word flag.

 
           		
           
+	        
             
    numbPtr := flag.Int("numb", 42, "an int")
     boolPtr := flag.Bool("fork", false, "a bool")
 

@@ -114,6 +119,7 @@ declaration function.

 
           		
           
+	        
             
    var svar string
     flag.StringVar(&svar, "svar", "bar", "a string var")
 

@@ -128,6 +134,7 @@ to execute the command-line parsing.

 
           		
           
+	        
             
    flag.Parse()
 

 
@@ -143,6 +150,7 @@ to get the actual option values.

 
           		
           
+	        
             
    fmt.Println("word:", *wordPtr)
     fmt.Println("numb:", *numbPtr)
     fmt.Println("fork:", *boolPtr)
@@ -166,6 +174,7 @@ binary directly.

 
           

           
+	        
             
$ go build command-line-flags.go
 

 
@@ -179,6 +188,7 @@ all flags.

 
           		
           
+	        
             
$ ./command-line-flags -word=opt -numb=7 -fork -svar=flag
 word: opt
 numb: 7
@@ -197,6 +207,7 @@ their default values.

 
           

           
+	        
             
$ ./command-line-flags -word=opt
 word: opt
 numb: 42
@@ -215,6 +226,7 @@ any flags.

 
           

           
+	        
             
$ ./command-line-flags -word=opt a1 a2 a3
 word: opt
 ...
@@ -232,6 +244,7 @@ will be interpreted as positional arguments).

 
           

           
+	        
             
$ ./command-line-flags -word=opt a1 a2 a3 -numb=7
 word: opt
 numb: 42
@@ -250,6 +263,7 @@ generated help text for the command-line program.

 
           

           
+	        
             
$ ./command-line-flags -h
 Usage of ./command-line-flags:
   -fork=false: a bool
@@ -269,6 +283,7 @@ an show the help text again.

 
           

           
+	        
             
$ ./command-line-flags -wat
 flag provided but not defined: -wat
 Usage of ./command-line-flags:
@@ -285,6 +300,7 @@ way to parameterize programs.

 
           

           
+	        
             
           
         

     

         
@@ -31,6 +30,7 @@ and numeric values.

@@ -40,6 +40,7 @@ and numeric values.

 
           
           

+	        
             
           
         

             
           
           

+	        
             
package main
 

 
@@ -51,6 +52,7 @@ and numeric values.

             
           		
           
+	        
             
import "fmt"
 import "math"
 

@@ -64,6 +66,7 @@ and numeric values.

 
           		
           
+	        
             
const s string = "constant"
 

 
@@ -75,6 +78,7 @@ and numeric values.

             
           		
           
+	        
             
func main() {
     fmt.Println(s)
 

@@ -89,6 +93,7 @@ statement can.

 
           		
           
+	        
             
    const n = 500000000
 

 
@@ -102,6 +107,7 @@ arbitrary precision.

 
           		
           
+	        
             
    const d = 3e20 / n
     fmt.Println(d)
 

@@ -116,6 +122,7 @@ one, such as by an explicit cast.

 
           		
           
+	        
             
    fmt.Println(int64(d))
 

 
@@ -131,6 +138,7 @@ assignment or function call. For example, here
 
           		
           
+	        
             
    fmt.Println(math.Sin(n))
 }
 

@@ -147,6 +155,7 @@ assignment or function call. For example, here
             
           		
           
+	        
             
$ go run constant.go 
 constant
 6e+11
diff --git a/public/defer b/public/defer
index 95462ed..130870b 100644
--- a/public/defer
+++ b/public/defer
@@ -20,7 +20,6 @@
   
     

       
Go by Example: Defer

-      
       
       
         
@@ -33,6 +32,7 @@ purposes of cleanup. defer is often used where e.g.
 
           
@@ -42,6 +42,7 @@ purposes of cleanup. defer is often used where e.g.
             
           

           

+	        
             
           
         

           

+	        
             
package main
 

 
@@ -53,6 +54,7 @@ purposes of cleanup. defer is often used where e.g.
             
           		
           
+	        
             
import "fmt"
 import "os"
 

@@ -68,6 +70,7 @@ do that with defer.

 
           		
           
+	        
             
func main() {
 

 
@@ -84,6 +87,7 @@ of the enclosing function (main), after
 
           		
           
+	        
             
    f := createFile("/tmp/defer.txt")
     defer closeFile(f)
     writeFile(f)
@@ -98,6 +102,7 @@ of the enclosing function (main), after
             
           

           
+	        
             
func createFile(p string) *os.File {
     fmt.Println("creating")
     f, err := os.Create(p)
@@ -116,6 +121,7 @@ of the enclosing function (main), after
             
           

           
+	        
             
func writeFile(f *os.File) {
     fmt.Println("writing")
     fmt.Fprintln(f, "data")
@@ -129,6 +135,7 @@ of the enclosing function (main), after
             
           

           
+	        
             
}
 

 
@@ -140,6 +147,7 @@ of the enclosing function (main), after
             
           		
           
+	        
             
func closeFile(f *os.File) {
     fmt.Println("closing")
     f.Close()
@@ -160,6 +168,7 @@ after being written.

 
           

           
+	        
             
$ go run defer.go
 creating
 writing
diff --git a/public/environment-variables b/public/environment-variables
index 63ebeca..cb61053 100644
--- a/public/environment-variables
+++ b/public/environment-variables
@@ -20,7 +20,6 @@
   
     

       
Go by Example: Environment Variables

-      
       
       
         
@@ -33,6 +32,7 @@ Let’s look at how to set, get, and list environment variables.

@@ -42,6 +42,7 @@ Let’s look at how to set, get, and list environment variables.

 
           
           

+	        
             
           
         

             
           
           

+	        
             
package main
 

 
@@ -53,6 +54,7 @@ Let’s look at how to set, get, and list environment variables.

             
           		
           
+	        
             
import "os"
 import "strings"
 import "fmt"
@@ -66,6 +68,7 @@ Let’s look at how to set, get, and list environment variables.

             
           

           
+	        
             
func main() {
 

 
@@ -81,6 +84,7 @@ environment.

 
           		
           
+	        
             
    os.Setenv("FOO", "1")
     fmt.Println("FOO:", os.Getenv("FOO"))
     fmt.Println("BAR:", os.Getenv("BAR"))
@@ -98,6 +102,7 @@ get the key and value. Here we print all the keys.

 
           

           
+	        
             
    fmt.Println()
     for _, e := range os.Environ() {
         pair := strings.Split(e, "=")
@@ -121,6 +126,7 @@ value for FOO that we set in the program, but that
 
           

           
+	        
             
$ go run environment-variables.go
 FOO: 1
 BAR: 
@@ -136,6 +142,7 @@ particular machine.

 
           

           
+	        
             
TERM_PROGRAM
 PATH
 SHELL
@@ -152,6 +159,7 @@ program picks that value up.

 
           

           
+	        
             
$ BAR=2 go run environment-variables.go
 FOO: 1
 BAR: 2
diff --git a/public/epoch b/public/epoch
index cc5161b..9f2ec37 100644
--- a/public/epoch
+++ b/public/epoch
@@ -20,7 +20,6 @@
   
     

       
Go by Example: Epoch

-      
       
       
         
@@ -33,6 +32,7 @@ Here’s how to do it in Go.

@@ -42,6 +42,7 @@ Here’s how to do it in Go.

diff --git a/public/errors b/public/errors
index dc25155..b07e219 100644
--- a/public/errors
+++ b/public/errors
@@ -20,7 +20,6 @@
   

       
Go by Example: Errors

-      
       
       

 
           
           

+	        
             
           
         

             
           
           

+	        
             
package main
 

 
@@ -53,6 +54,7 @@ Here’s how to do it in Go.

             
           		
           
+	        
             
import "fmt"
 import "time"
 

@@ -65,6 +67,7 @@ Here’s how to do it in Go.

             
           		
           
+	        
             
func main() {
 

 
@@ -79,6 +82,7 @@ nanoseconds, respectively.

 
           		
           
+	        
             
    now := time.Now()
     secs := now.Unix()
     nanos := now.UnixNano()
@@ -96,6 +100,7 @@ dive from nanoseconds.

 
           

           
+	        
             
    millis := nanos / 1000000
     fmt.Println(secs)
     fmt.Println(millis)
@@ -112,6 +117,7 @@ since the epoch into the corresponding time.

 
           

           
+	        
             
    fmt.Println(time.Unix(secs, 0))
     fmt.Println(time.Unix(0, nanos))
 }
@@ -129,6 +135,7 @@ since the epoch into the corresponding time.

             
           

           
+	        
             
$ go run epoch.go 
 2012-10-31 16:13:58.292387 +0000 UTC
 1351700038
@@ -148,6 +155,7 @@ parsing and formatting.

 
           

           
+	        
             
           
         

     

         
@@ -37,6 +36,7 @@ non-error tasks.

@@ -46,6 +46,7 @@ non-error tasks.

diff --git a/public/execing-processes b/public/execing-processes
index 2700243..baa501a 100644
--- a/public/execing-processes
+++ b/public/execing-processes
@@ -20,7 +20,6 @@
   

       
Go by Example: Exec'ing Processes

-      
       
       

 
           
           

+	        
             
           
         

             
           
           

+	        
             
package main
 

 
@@ -57,6 +58,7 @@ non-error tasks.

             
           		
           
+	        
             
import "errors"
 import "fmt"
 

@@ -71,6 +73,7 @@ have type error, a built-in interface.

 
           		
           
+	        
             
func f1(arg int) (int, error) {
     if arg == 42 {
 

@@ -85,6 +88,7 @@ with the given error message.

 
           		
           
+	        
             
        return -1, errors.New("can't work with 42")
 

 
@@ -96,6 +100,7 @@ with the given error message.

             
           		
           
+	        
             
    }
 

 
@@ -109,6 +114,7 @@ there was no error.

 
           		
           
+	        
             
    return arg + 3, nil
 }
 

@@ -125,6 +131,7 @@ to explicitly represent an argument error.

 
           		
           
+	        
             
type argError struct {
     arg  int
     prob string
@@ -139,6 +146,7 @@ to explicitly represent an argument error.

             
           

           
+	        
             
func (e *argError) Error() string {
     return fmt.Sprintf("%d - %s", e.arg, e.prob)
 }
@@ -152,6 +160,7 @@ to explicitly represent an argument error.

             
           

           
+	        
             
func f2(arg int) (int, error) {
     if arg == 42 {
 

@@ -167,6 +176,7 @@ fields arg and prob.

 
           		
           
+	        
             
        return -1, &argError{arg, "can't work with it"}
     }
     return arg + 3, nil
@@ -181,6 +191,7 @@ fields arg and prob.

             
           

           
+	        
             
func main() {
 

 
@@ -196,6 +207,7 @@ idiom in Go code.

 
           		
           
+	        
             
    for _, i := range []int{7, 42} {
         if r, e := f1(i); e != nil {
             fmt.Println("f1 failed:", e)
@@ -224,6 +236,7 @@ assertion.

 
           

           
+	        
             
    _, e := f2(42)
     if ae, ok := e.(*argError); ok {
         fmt.Println(ae.arg)
@@ -244,6 +257,7 @@ assertion.

             
           

           
+	        
             
$ go run errors.go
 f1 worked: 10
 f1 failed: can't work with 42
@@ -263,6 +277,7 @@ on the Go blog for more on error handling.

 
           

           
+	        
             
           
         

     

         
@@ -38,6 +37,7 @@ function.

@@ -47,6 +47,7 @@ function.

diff --git a/public/exit b/public/exit
index 3b61b94..3188ddb 100644
--- a/public/exit
+++ b/public/exit
@@ -20,7 +20,6 @@
   

       
Go by Example: Exit

-      
       
       

 
           
           

+	        
             
           
         

             
           
           

+	        
             
package main
 

 
@@ -58,6 +59,7 @@ function.

             
           		
           
+	        
             
import "syscall"
 import "os"
 import "os/exec"
@@ -71,6 +73,7 @@ function.

             
           

           
+	        
             
func main() {
 

 
@@ -86,6 +89,7 @@ we’ll use exec.LookPath to find it (probably
 
           		
           
+	        
             
    binary, lookErr := exec.LookPath("ls")
     if lookErr != nil {
         panic(lookErr)
@@ -104,6 +108,7 @@ be the program name.

 
           

           
+	        
             
    args := []string{"ls", "-a", "-l", "-h"}
 

 
@@ -118,6 +123,7 @@ environment.

 
           		
           
+	        
             
    env := os.Environ()
 

 
@@ -134,6 +140,7 @@ value.

 
           		
           
+	        
             
    execErr := syscall.Exec(binary, args, env)
     if execErr != nil {
         panic(execErr)
@@ -154,6 +161,7 @@ value.

 
           

           
+	        
             
$ go run execing-processes.go
 total 16
 drwxr-xr-x  4 mark 136B Oct 3 16:29 .
@@ -173,6 +181,7 @@ processes covers most use cases for fork.

 
           

           
+	        
             
           
         

     

         
@@ -31,6 +30,7 @@ status.

@@ -40,6 +40,7 @@ status.

@@ -119,6 +125,7 @@ will be picked up by go and printed.

diff --git a/public/for b/public/for
index 2bb0487..83e76a3 100644
--- a/public/for
+++ b/public/for
@@ -20,7 +20,6 @@
   

       
Go by Example: For

-      
       
       

 
           
           

+	        
             
           
         

             
           
           

+	        
             
package main
 

 
@@ -51,6 +52,7 @@ status.

             
           		
           
+	        
             
import "fmt"
 import "os"
 

@@ -63,6 +65,7 @@ status.

             
           		
           
+	        
             
func main() {
 

 
@@ -76,6 +79,7 @@ this fmt.Println will never be called.

 
           		
           
+	        
             
    defer fmt.Println("!")
 

 
@@ -88,6 +92,7 @@ this fmt.Println will never be called.

 
           		
           
+	        
             
    os.Exit(3)
 }
 

@@ -104,6 +109,7 @@ use os.Exit.

 
           		
           
+	        
             
           
         

 
           
           

+	        
             
$ go run exit.go
 exit status 3
 

@@ -133,6 +140,7 @@ the status in the terminal.

 
           		
           
+	        
             
$ go build exit.go
 $ ./exit
 $ echo $?
@@ -148,6 +156,7 @@ the status in the terminal.

 
           

           
+	        
             
           
         

     

         
@@ -31,6 +30,7 @@ three basic types of for loops.

@@ -40,6 +40,7 @@ three basic types of for loops.

diff --git a/public/functions b/public/functions
index ddb42f4..267ae28 100644
--- a/public/functions
+++ b/public/functions
@@ -20,7 +20,6 @@
   

       
Go by Example: Functions

-      
       
       

 
           
           

+	        
             
           
         

             
           
           

+	        
             
package main
 

 
@@ -51,6 +52,7 @@ three basic types of for loops.

             
           		
           
+	        
             
import "fmt"
 

 
@@ -62,6 +64,7 @@ three basic types of for loops.

             
           		
           
+	        
             
func main() {
 

 
@@ -74,6 +77,7 @@ three basic types of for loops.

 
           		
           
+	        
             
    i := 1
     for i <= 3 {
         fmt.Println(i)
@@ -90,6 +94,7 @@ three basic types of for loops.

 
           

           
+	        
             
    for j := 7; j <= 9; j++ {
         fmt.Println(j)
     }
@@ -106,6 +111,7 @@ the enclosing function.

 
           

           
+	        
             
    for {
         fmt.Println("loop")
         break
@@ -125,6 +131,7 @@ the enclosing function.

             
           

           
+	        
             
$ go run for.go
 1
 2
@@ -146,6 +153,7 @@ structures.

 
           

           
+	        
             
           
         

     

         
@@ -31,6 +30,7 @@ functions with a few different examples.

@@ -40,6 +40,7 @@ functions with a few different examples.

diff --git a/public/goroutines b/public/goroutines
index 1b03964..67fe18b 100644
--- a/public/goroutines
+++ b/public/goroutines
@@ -20,7 +20,6 @@
   

       
Go by Example: Goroutines

-      
       
       

 
           
           

+	        
             
           
         

             
           
           

+	        
             
package main
 

 
@@ -51,6 +52,7 @@ functions with a few different examples.

             
           		
           
+	        
             
import "fmt"
 

 
@@ -64,6 +66,7 @@ their sum as an int.

 
           		
           
+	        
             
func plus(a int, b int) int {
 

 
@@ -78,6 +81,7 @@ expression.

 
           		
           
+	        
             
    return a + b
 }
 

@@ -90,6 +94,7 @@ expression.

             
           		
           
+	        
             
func main() {
 

 
@@ -103,6 +108,7 @@ expression.

 
           		
           
+	        
             
    res := plus(1, 2)
     fmt.Println("1+2 =", res)
 }
@@ -120,6 +126,7 @@ expression.

             
           

           
+	        
             
$ go run functions.go 
 1+2 = 3
 

@@ -134,6 +141,7 @@ multiple return values, which we’ll look at next.

 
           		
           
+	        
             
           
         

     

         
@@ -30,6 +29,7 @@
 
           
@@ -39,6 +39,7 @@
             
           
diff --git a/public/hello-world b/public/hello-world
index afea790..bfb0c69 100644
--- a/public/hello-world
+++ b/public/hello-world
@@ -20,7 +20,6 @@
   

       
Go by Example: Hello World

-      
       
       

           

+	        
             
           
         

           

+	        
             
package main
 

 
@@ -50,6 +51,7 @@
             
           		
           
+	        
             
import "fmt"
 

 
@@ -61,6 +63,7 @@
             
           		
           
+	        
             
func f(from string) {
     for i := 0; i < 3; i++ {
         fmt.Println(from, ":", i)
@@ -76,6 +79,7 @@
             
           

           
+	        
             
func main() {
 

 
@@ -90,6 +94,7 @@ synchronously.

 
           		
           
+	        
             
    f("direct")
 

 
@@ -104,6 +109,7 @@ concurrently with the calling one.

 
           		
           
+	        
             
    go f("goroutine")
 

 
@@ -117,6 +123,7 @@ function call.

 
           		
           
+	        
             
    go func(msg string) {
         fmt.Println(msg)
     }("going")
@@ -134,6 +141,7 @@ before the program exits.

 
           

           
+	        
             
    var input string
     fmt.Scanln(&input)
     fmt.Println("done")
@@ -156,6 +164,7 @@ goroutines being run concurrently by the Go runtime.

 
           

           
+	        
             
$ go run goroutines.go
 direct : 0
 direct : 1
@@ -178,6 +187,7 @@ concurrent Go programs: channels.

 
           

           
+	        
             
           
         

     

         
@@ -31,6 +30,7 @@ message. Here’s the full source code.

diff --git a/public/if-else b/public/if-else
index 8c1ee77..c54f82e 100644
--- a/public/if-else
+++ b/public/if-else
@@ -20,7 +20,6 @@
   

       
Go by Example: If/Else

-      
       
       

 
           
           

+	        
             
package main
 

 
@@ -42,6 +42,7 @@ message. Here’s the full source code.

             
           		
           
+	        
             
import "fmt"
 

 
@@ -53,6 +54,7 @@ message. Here’s the full source code.

             
           		
           
+	        
             
func main() {
     fmt.Println("hello world")
 }
@@ -72,6 +74,7 @@ use go run.

 
           

           
+	        
             
$ go run hello-world.go
 hello world
 

@@ -86,6 +89,7 @@ binaries. We can do this using go build.

 
           		
           
+	        
             
$ go build hello-world.go
 $ ls
 hello-world	hello-world.go
@@ -100,6 +104,7 @@ binaries. We can do this using go build.

 
           

           
+	        
             
$ ./hello-world
 hello world
 

@@ -114,6 +119,7 @@ learn more about the language.

 
           		
           
+	        
             
           
         

     

         
@@ -31,6 +30,7 @@ straight-forward.

@@ -40,6 +40,7 @@ straight-forward.

@@ -139,6 +146,7 @@ in Go, but that the brackets are required.

diff --git a/public/interfaces b/public/interfaces
index 2c6efc6..3330a70 100644
--- a/public/interfaces
+++ b/public/interfaces
@@ -20,7 +20,6 @@
   

       
Go by Example: Interfaces

-      
       
       

 
           
           

+	        
             
           
         

             
           
           

+	        
             
package main
 

 
@@ -51,6 +52,7 @@ straight-forward.

             
           		
           
+	        
             
import "fmt"
 

 
@@ -62,6 +64,7 @@ straight-forward.

             
           		
           
+	        
             
func main() {
 

 
@@ -74,6 +77,7 @@ straight-forward.

 
           		
           
+	        
             
    if 7%2 == 0 {
         fmt.Println("7 is even")
     } else {
@@ -90,6 +94,7 @@ straight-forward.

 
           

           
+	        
             
    if 8%4 == 0 {
         fmt.Println("8 is divisible by 4")
     }
@@ -106,6 +111,7 @@ branches.

 
           

           
+	        
             
    if num := 9; num < 0 {
         fmt.Println(num, "is negative")
     } else if num < 10 {
@@ -126,6 +132,7 @@ in Go, but that the brackets are required.

 
           

           
+	        
             
           
         

             
           
           

+	        
             
$ go run if-else.go 
 7 is odd
 8 is divisible by 4
@@ -156,6 +164,7 @@ for basic conditions.

 
           

           
+	        
             
           
         

     

         
@@ -31,6 +30,7 @@ signatures.

@@ -40,6 +40,7 @@ signatures.

diff --git a/public/json b/public/json
index 1928d21..ebe459d 100644
--- a/public/json
+++ b/public/json
@@ -20,7 +20,6 @@
   

       
Go by Example: JSON

-      
       
       

 
           
           

+	        
             
           
         

             
           
           

+	        
             
package main
 

 
@@ -51,6 +52,7 @@ signatures.

             
           		
           
+	        
             
import "fmt"
 import "math"
 

@@ -64,6 +66,7 @@ signatures.

 
           		
           
+	        
             
type geometry interface {
     area() float64
     perim() float64
@@ -80,6 +83,7 @@ signatures.

 
           

           
+	        
             
type square struct {
     width, height float64
 }
@@ -99,6 +103,7 @@ implement geometry on squares.

 
           

           
+	        
             
func (s square) area() float64 {
     return s.width * s.height
 }
@@ -116,6 +121,7 @@ implement geometry on squares.

 
           

           
+	        
             
func (c circle) area() float64 {
     return math.Pi * c.radius * c.radius
 }
@@ -136,6 +142,7 @@ to work on any geometry.

 
           

           
+	        
             
func measure(g geometry) {
     fmt.Println(g)
     fmt.Println(g.area())
@@ -151,6 +158,7 @@ to work on any geometry.

             
           

           
+	        
             
func main() {
     s := square{width: 3, height: 4}
     c := circle{radius: 5}
@@ -168,6 +176,7 @@ these structs as arguments to measure.

 
           

           
+	        
             
    measure(s)
     measure(c)
 }
@@ -185,6 +194,7 @@ these structs as arguments to measure.

             
           

           
+	        
             
$ go run interfaces.go
 {3 4}
 12
@@ -204,6 +214,7 @@ these structs as arguments to measure.

 
           

           
+	        
             
           
         

     

         
@@ -32,6 +31,7 @@ data types.

@@ -41,6 +41,7 @@ data types.

diff --git a/public/line-filters b/public/line-filters
index 51a6c3c..b0dd210 100644
--- a/public/line-filters
+++ b/public/line-filters
@@ -20,7 +20,6 @@
   

       
Go by Example: Line Filters

-      
       
       

 
           
           

+	        
             
           
         

             
           
           

+	        
             
package main
 

 
@@ -52,6 +53,7 @@ data types.

             
           		
           
+	        
             
import "encoding/json"
 import "fmt"
 import "os"
@@ -67,6 +69,7 @@ decoding of custom types below.

 
           

           
+	        
             
type Response1 struct {
     Page   int
     Fruits []string
@@ -85,6 +88,7 @@ decoding of custom types below.

             
           

           
+	        
             
func main() {
 

 
@@ -99,6 +103,7 @@ values.

 
           		
           
+	        
             
    bolB, _ := json.Marshal(true)
     fmt.Println(string(bolB))
 

@@ -111,6 +116,7 @@ values.

             
           		
           
+	        
             
    intB, _ := json.Marshal(1)
     fmt.Println(string(intB))
 

@@ -123,6 +129,7 @@ values.

             
           		
           
+	        
             
    fltB, _ := json.Marshal(2.34)
     fmt.Println(string(fltB))
 

@@ -135,6 +142,7 @@ values.

             
           		
           
+	        
             
    strB, _ := json.Marshal("gopher")
     fmt.Println(string(strB))
 

@@ -149,6 +157,7 @@ to JSON arrays and objects as you’d expect.

 
           		
           
+	        
             
    slcD := []string{"apple", "peach", "pear"}
     slcB, _ := json.Marshal(slcD)
     fmt.Println(string(slcB))
@@ -162,6 +171,7 @@ to JSON arrays and objects as you’d expect.

             
           

           
+	        
             
    mapD := map[string]int{"apple": 5, "lettuce": 7}
     mapB, _ := json.Marshal(mapD)
     fmt.Println(string(mapB))
@@ -179,6 +189,7 @@ use those names as the JSON keys.

 
           

           
+	        
             
    res1D := &Response1{
         Page:   1,
         Fruits: []string{"apple", "peach", "pear"}}
@@ -198,6 +209,7 @@ of such tags.

 
           

           
+	        
             
    res2D := &Response2{
         Page:   1,
         Fruits: []string{"apple", "peach", "pear"}}
@@ -216,6 +228,7 @@ structure.

 
           

           
+	        
             
    byt := []byte(`{"num":6.0,"strs":["a","b"]}`)
 

 
@@ -231,6 +244,7 @@ to arbitrary data types.

 
           		
           
+	        
             
    var dat map[string]interface{}
 

 
@@ -244,6 +258,7 @@ associated errors.

 
           		
           
+	        
             
    if err := json.Unmarshal(byt, &dat); err != nil {
         panic(err)
     }
@@ -262,6 +277,7 @@ the expected float64 type.

 
           

           
+	        
             
    num := dat["num"].(float64)
     fmt.Println(num)
 

@@ -276,6 +292,7 @@ casts.

 
           		
           
+	        
             
    strs := dat["strs"].([]interface{})
     str1 := strs[0].(string)
     fmt.Println(str1)
@@ -294,6 +311,7 @@ data.

 
           

           
+	        
             
    str := `{"page": 1, "fruits": ["apple", "peach"]}`
     res := &Response2{}
     json.Unmarshal([]byte(str), &res)
@@ -314,6 +332,7 @@ stream JSON encodings directly to os.Writers like
 
           

           
+	        
             
    enc := json.NewEncoder(os.Stdout)
     d := map[string]int{"apple": 5, "lettuce": 7}
     enc.Encode(d)
@@ -332,6 +351,7 @@ stream JSON encodings directly to os.Writers like
             
           

           
+	        
             
$ go run json.go
 true
 1
@@ -361,6 +381,7 @@ for more.

 
           

           
+	        
             
           
         

     

         
@@ -33,6 +32,7 @@ line filters.

@@ -45,6 +45,7 @@ pattern to write your own Go line filters.

 
           
           

+	        
             
           
         

 
           
           

+	        
             
package main
 

 
@@ -56,6 +57,7 @@ pattern to write your own Go line filters.

             
           		
           
+	        
             
import (
     "bufio"
     "fmt"
@@ -73,6 +75,7 @@ pattern to write your own Go line filters.

             
           

           
+	        
             
func main() {
 

 
@@ -87,6 +90,7 @@ that we’ll use to read input line-by-line.

 
           		
           
+	        
             
    rdr := bufio.NewReader(os.Stdin)
     out := os.Stdout
 

@@ -103,6 +107,7 @@ successive input lines.

 
           		
           
+	        
             
    for {
         switch line, err := rdr.ReadString('\n'); err {
 

@@ -118,6 +123,7 @@ error on this write as we do on the read.

 
           		
           
+	        
             
        case nil:
             ucl := strings.ToUpper(line)
             if _, err = out.WriteString(ucl); err != nil {
@@ -136,6 +142,7 @@ end of input, so exit gracefully in that case.

 
           

           
+	        
             
        case io.EOF:
             os.Exit(0)
 

@@ -150,6 +157,7 @@ error and exit with non-zero status.

 
           		
           
+	        
             
        default:
             fmt.Fprintln(os.Stderr, "error:", err)
             os.Exit(1)
@@ -172,6 +180,7 @@ lowercase lines.

 
           

           
+	        
             
$ echo 'hello'   > /tmp/lines
 $ echo 'filter' >> /tmp/lines
 

@@ -185,6 +194,7 @@ lowercase lines.

 
           		
           
+	        
             
$ cat /tmp/lines | go run line-filters.go
 HELLO
 FILTER
diff --git a/public/maps b/public/maps
index 0ddf290..f08cdb9 100644
--- a/public/maps
+++ b/public/maps
@@ -20,7 +20,6 @@
   
     

       
Go by Example: Maps

-      
       
       
         
@@ -31,6 +30,7 @@
 
           
@@ -40,6 +40,7 @@
             
           

           

+	        
             
           
         

           

+	        
             
package main
 

 
@@ -51,6 +52,7 @@
             
           		
           
+	        
             
import "fmt"
 

 
@@ -62,6 +64,7 @@
             
           		
           
+	        
             
func main() {
 

 
@@ -75,6 +78,7 @@
 
           		
           
+	        
             
    m := make(map[string]int)
 

 
@@ -88,6 +92,7 @@ syntax.

 
           		
           
+	        
             
    m["k1"] = 7
     m["k2"] = 13
 

@@ -102,6 +107,7 @@ its key/value pairs.

 
           		
           
+	        
             
    fmt.Println("map:", m)
 

 
@@ -114,6 +120,7 @@ its key/value pairs.

 
           		
           
+	        
             
    v1 := m["k1"]
     fmt.Println("v1: ", v1)
 

@@ -128,6 +135,7 @@ pairs when called on a map.

 
           		
           
+	        
             
    fmt.Println("len:", len(m))
 

 
@@ -141,6 +149,7 @@ a map.

 
           		
           
+	        
             
    delete(m, "k2")
     fmt.Println("map:", m)
 

@@ -158,6 +167,7 @@ like 0 or "".

 
           		
           
+	        
             
    _, prs := m["k2"]
     fmt.Println("prs:", prs)
 

@@ -172,6 +182,7 @@ the same line with this syntax.

 
           		
           
+	        
             
    n := map[string]int{"foo": 1, "bar": 2}
     fmt.Println("map:", n)
 }
@@ -191,6 +202,7 @@ printed with fmt.Println.

 
           

           
+	        
             
$ go run maps.go 
 map: map[k1:7 k2:13]
 v1:  7
diff --git a/public/methods b/public/methods
index 701f331..1d2a96c 100644
--- a/public/methods
+++ b/public/methods
@@ -20,7 +20,6 @@
   
     

       
Go by Example: Methods

-      
       
       
         
@@ -30,6 +29,7 @@
 
           
@@ -39,6 +39,7 @@
             
           
diff --git a/public/multiple-return-values b/public/multiple-return-values
index 9cdf349..d81ced5 100644
--- a/public/multiple-return-values
+++ b/public/multiple-return-values
@@ -20,7 +20,6 @@
   

       
Go by Example: Multiple Return Values

-      
       
       

           

+	        
             
           
         

           

+	        
             
package main
 

 
@@ -50,6 +51,7 @@
             
           		
           
+	        
             
import "fmt"
 

 
@@ -61,6 +63,7 @@
             
           		
           
+	        
             
type rect struct {
     width, height int
 }
@@ -75,6 +78,7 @@
 
           

           
+	        
             
func (r *rect) area() int {
     return r.width * r.height
 }
@@ -90,6 +94,7 @@ receiver types. Here’s an example of a value receiver.

 
           

           
+	        
             
func (r rect) perim() int {
     return 2*r.width + 2*r.height
 }
@@ -103,6 +108,7 @@ receiver types. Here’s an example of a value receiver.

             
           

           
+	        
             
func main() {
     r := rect{width: 10, height: 5}
 

@@ -116,6 +122,7 @@ receiver types. Here’s an example of a value receiver.

 
           		
           
+	        
             
    fmt.Println("area: ", r.area())
     fmt.Println("perim:", r.perim())
 

@@ -133,6 +140,7 @@ receiving struct.

 
           		
           
+	        
             
    rp := &r
     fmt.Println("area: ", rp.area())
     fmt.Println("perim:", rp.perim())
@@ -151,6 +159,7 @@ receiving struct.

             
           

           
+	        
             
$ go run methods.go 
 area:  50
 perim: 30
@@ -168,6 +177,7 @@ naming related sets of methods: interfaces.

 
           

           
+	        
             
           
         

     

         
@@ -32,6 +31,7 @@ to return both result and error values from a function.

@@ -41,6 +41,7 @@ to return both result and error values from a function.

diff --git a/public/mutexes b/public/mutexes
index c588d23..c830315 100644
--- a/public/mutexes
+++ b/public/mutexes
@@ -20,7 +20,6 @@
   

       
Go by Example: Mutexes

-      
       
       

 
           
           

+	        
             
           
         

             
           
           

+	        
             
package main
 

 
@@ -52,6 +53,7 @@ to return both result and error values from a function.

             
           		
           
+	        
             
import "fmt"
 

 
@@ -65,6 +67,7 @@ the function returns 2 ints.

 
           		
           
+	        
             
func vals() (int, int) {
     return 3, 7
 }
@@ -78,6 +81,7 @@ the function returns 2 ints.

             
           

           
+	        
             
func main() {
 

 
@@ -91,6 +95,7 @@ call with multiple assignment.

 
           		
           
+	        
             
    a, b := vals()
     fmt.Println(a)
     fmt.Println(b)
@@ -106,6 +111,7 @@ use the blank identifier _.

 
           

           
+	        
             
    _, c := vals()
     fmt.Println(c)
 }
@@ -123,6 +129,7 @@ use the blank identifier _.

             
           

           
+	        
             
$ go run multiple-return-values.go
 3
 7
@@ -139,6 +146,7 @@ feature of Go functions; we’ll look at this next.

 
           

           
+	        
             
           
         

     

         
@@ -33,6 +32,7 @@ to safely access data across multiple goroutines.

@@ -42,6 +42,7 @@ to safely access data across multiple goroutines.

diff --git a/public/non-blocking-channel-operations b/public/non-blocking-channel-operations
index 55a6126..de4e98c 100644
--- a/public/non-blocking-channel-operations
+++ b/public/non-blocking-channel-operations
@@ -20,7 +20,6 @@
   

       
Go by Example: Non-Blocking Channel Operations

-      
       
       

 
           
           

+	        
             
           
         

             
           
           

+	        
             
package main
 

 
@@ -53,6 +54,7 @@ to safely access data across multiple goroutines.

             
           		
           
+	        
             
import (
     "fmt"
     "math/rand"
@@ -71,6 +73,7 @@ to safely access data across multiple goroutines.

             
           

           
+	        
             
func main() {
 

 
@@ -83,6 +86,7 @@ to safely access data across multiple goroutines.

 
           		
           
+	        
             
    var state = make(map[int]int)
 

 
@@ -95,6 +99,7 @@ to safely access data across multiple goroutines.

 
           		
           
+	        
             
    var mutex = &sync.Mutex{}
 

 
@@ -109,6 +114,7 @@ operations we perform against the state.

 
           		
           
+	        
             
    var ops int64 = 0
 

 
@@ -122,6 +128,7 @@ reads against the state.

 
           		
           
+	        
             
    for r := 0; r < 100; r++ {
         go func() {
             total := 0
@@ -142,6 +149,7 @@ the ops count.

 
           

           
+	        
             
                key := rand.Intn(5)
                 mutex.Lock()
                 total += state[key]
@@ -165,6 +173,7 @@ case we need to do it manually.

 
           

           
+	        
             
                runtime.Gosched()
             }
         }()
@@ -181,6 +190,7 @@ using the same pattern we did for reads.

 
           

           
+	        
             
    for w := 0; w < 10; w++ {
         go func() {
             for {
@@ -206,6 +216,7 @@ using the same pattern we did for reads.

 
           

           
+	        
             
    time.Sleep(time.Second)
 

 
@@ -218,6 +229,7 @@ using the same pattern we did for reads.

 
           		
           
+	        
             
    opsFinal := atomic.LoadInt64(&ops)
     fmt.Println("ops:", opsFinal)
 

@@ -231,6 +243,7 @@ using the same pattern we did for reads.

 
           		
           
+	        
             
    mutex.Lock()
     fmt.Println("state:", state)
     mutex.Unlock()
@@ -252,6 +265,7 @@ using the same pattern we did for reads.

 
           

           
+	        
             
$ go run mutexes.go
 ops: 3598302
 state: map[1:38 4:98 2:23 3:85 0:44]
@@ -267,6 +281,7 @@ management task using only goroutines and channels.

 
           

           
+	        
             
           
         

     

         
@@ -33,6 +32,7 @@ non-blocking multi-way selects.

@@ -42,6 +42,7 @@ non-blocking multi-way selects.

 
           
           

+	        
             
           
         

             
           
           

+	        
             
package main
 

 
@@ -53,6 +54,7 @@ non-blocking multi-way selects.

             
           		
           
+	        
             
import "fmt"
 

 
@@ -64,6 +66,7 @@ non-blocking multi-way selects.

             
           		
           
+	        
             
func main() {
     messages := make(chan string)
     signals := make(chan bool)
@@ -81,6 +84,7 @@ it will immediately take the default case.

 
           

           
+	        
             
    select {
     case msg := <-messages:
         fmt.Println("received message", msg)
@@ -98,6 +102,7 @@ it will immediately take the default case.

 
           

           
+	        
             
    msg := "hi"
     select {
     case messages <- msg:
@@ -119,6 +124,7 @@ on both messages and signals.

 
           

           
+	        
             
    select {
     case msg := <-messages:
         fmt.Println("received message", msg)
@@ -142,6 +148,7 @@ on both messages and signals.

             
           

           
+	        
             
$ go run non-blocking-channel-operations.go 
 no message received
 no message sent
diff --git a/public/number-parsing b/public/number-parsing
index b01d116..910359f 100644
--- a/public/number-parsing
+++ b/public/number-parsing
@@ -20,7 +20,6 @@
   
     

       
Go by Example: Number Parsing

-      
       
       
         
@@ -31,6 +30,7 @@ in many programs; here’s how to do it in Go.

@@ -40,6 +40,7 @@ in many programs; here’s how to do it in Go.

diff --git a/public/panic b/public/panic
index c4ea20a..202bf66 100644
--- a/public/panic
+++ b/public/panic
@@ -20,7 +20,6 @@
   

       
Go by Example: Panic

-      
       
       

 
           
           

+	        
             
           
         

             
           
           

+	        
             
package main
 

 
@@ -53,6 +54,7 @@ parsing.

 
           		
           
+	        
             
import "strconv"
 import "fmt"
 

@@ -65,6 +67,7 @@ parsing.

             
           		
           
+	        
             
func main() {
 

 
@@ -78,6 +81,7 @@ precision to parse.

 
           		
           
+	        
             
    f, _ := strconv.ParseFloat("1.234", 64)
     fmt.Println(f)
 

@@ -93,6 +97,7 @@ bits.

 
           		
           
+	        
             
    i, _ := strconv.ParseInt("123", 0, 64)
     fmt.Println(i)
 

@@ -106,6 +111,7 @@ bits.

 
           		
           
+	        
             
    d, _ := strconv.ParseInt("0x1c8", 0, 64)
     fmt.Println(d)
 

@@ -119,6 +125,7 @@ bits.

 
           		
           
+	        
             
    u, _ := strconv.ParseUint("789", 0, 64)
     fmt.Println(u)
 

@@ -133,6 +140,7 @@ bits.

 
           		
           
+	        
             
    k, _ := strconv.Atoi("135")
     fmt.Println(k)
 

@@ -146,6 +154,7 @@ bits.

 
           		
           
+	        
             
    _, e := strconv.Atoi("wat")
     fmt.Println(e)
 }
@@ -163,6 +172,7 @@ bits.

             
           

           
+	        
             
$ go run number-parsing.go 
 1.234
 123
@@ -181,6 +191,7 @@ bits.

 
           

           
+	        
             
           
         

     

         
@@ -33,6 +32,7 @@ aren’t prepared to handle gracefully.

@@ -42,6 +42,7 @@ aren’t prepared to handle gracefully.

diff --git a/public/pointers b/public/pointers
index 4f2d6ad..bc6e8ba 100644
--- a/public/pointers
+++ b/public/pointers
@@ -20,7 +20,6 @@
   

       
Go by Example: Pointers

-      
       
       

 
           
           

+	        
             
           
         

             
           
           

+	        
             
package main
 

 
@@ -53,6 +54,7 @@ aren’t prepared to handle gracefully.

             
           		
           
+	        
             
import "os"
 

 
@@ -64,6 +66,7 @@ aren’t prepared to handle gracefully.

             
           		
           
+	        
             
func main() {
 

 
@@ -78,6 +81,7 @@ site designed to panic.

 
           		
           
+	        
             
    panic("a problem")
 

 
@@ -93,6 +97,7 @@ returns an error value that we don’t know how to
 
           		
           
+	        
             
    _, err := os.Create("/tmp/file")
     if err != nil {
         panic(err)
@@ -115,6 +120,7 @@ a non-zero status.

 
           

           
+	        
             
$ go run panic.go
 panic: a problem
 

@@ -127,6 +133,7 @@ a non-zero status.

             
           		
           
+	        
             
goroutine 1 [running]:
 main.main()
 	/.../panic.go:12 +0x47
@@ -145,6 +152,7 @@ to use error-indicating return values wherever possible.

 
           

           
+	        
             
           
         

     

         
@@ -32,6 +31,7 @@ within your program.

@@ -41,6 +41,7 @@ within your program.

 
           
           

+	        
             
           
         

             
           
           

+	        
             
package main
 

 
@@ -52,6 +53,7 @@ within your program.

             
           		
           
+	        
             
import "fmt"
 

 
@@ -68,6 +70,7 @@ from the one in the calling function.

 
           		
           
+	        
             
func zeroval(ival int) {
     ival = 0
 }
@@ -87,6 +90,7 @@ value at the referenced address.

 
           

           
+	        
             
func zeroptr(iptr *int) {
     *iptr = 0
 }
@@ -100,6 +104,7 @@ value at the referenced address.

             
           

           
+	        
             
func main() {
     i := 1
     fmt.Println("initial:", i)
@@ -113,6 +118,7 @@ value at the referenced address.

             
           

           
+	        
             
    zeroval(i)
     fmt.Println("zeroval:", i)
 

@@ -127,6 +133,7 @@ i.e. a pointer to i.

 
           		
           
+	        
             
    zeroptr(&i)
     fmt.Println("zeroptr:", i)
 

@@ -140,6 +147,7 @@ i.e. a pointer to i.

 
           		
           
+	        
             
    fmt.Println("pointer:", &i)
 }
 

@@ -159,6 +167,7 @@ the memory address for that variable.

 
           		
           
+	        
             
$ go run pointers.go
 initial: 1
 zeroval: 1
diff --git a/public/random-numbers b/public/random-numbers
index 1f36a81..25ba951 100644
--- a/public/random-numbers
+++ b/public/random-numbers
@@ -20,7 +20,6 @@
   
     

       
Go by Example: Random Numbers

-      
       
       
         
@@ -32,6 +31,7 @@ generation.

@@ -41,6 +41,7 @@ generation.

diff --git a/public/range b/public/range
index a4339c4..209c982 100644
--- a/public/range
+++ b/public/range
@@ -20,7 +20,6 @@
   

       
Go by Example: Range

-      
       
       

 
           
           

+	        
             
           
         

             
           
           

+	        
             
package main
 

 
@@ -52,6 +53,7 @@ generation.

             
           		
           
+	        
             
import "fmt"
 import "math/rand"
 

@@ -64,6 +66,7 @@ generation.

             
           		
           
+	        
             
func main() {
 

 
@@ -77,6 +80,7 @@ generation.

 
           		
           
+	        
             
    fmt.Print(rand.Intn(100), ",")
     fmt.Print(rand.Intn(100))
     fmt.Println()
@@ -92,6 +96,7 @@ generation.

 
           

           
+	        
             
    fmt.Println(rand.Float64())
 

 
@@ -105,6 +110,7 @@ other ranges, for example 5.0 <= f' < 10.0.

 
           		
           
+	        
             
    fmt.Print((rand.Float64()*5)+5, ",")
     fmt.Print((rand.Float64() * 5) + 5)
     fmt.Println()
@@ -120,6 +126,7 @@ give it a well-known seed.

 
           

           
+	        
             
    s1 := rand.NewSource(42)
     r1 := rand.New(s1)
 

@@ -134,6 +141,7 @@ functions on the rand package.

 
           		
           
+	        
             
    fmt.Print(r1.Intn(100), ",")
     fmt.Print(r1.Intn(100))
     fmt.Println()
@@ -149,6 +157,7 @@ produces the same sequence of random numbers.

 
           

           
+	        
             
    s2 := rand.NewSource(42)
     r2 := rand.New(s2)
     fmt.Print(r2.Intn(100), ",")
@@ -169,6 +178,7 @@ produces the same sequence of random numbers.

             
           

           
+	        
             
$ go run random-numbers.go 
 81,87
 0.6645600532184904
@@ -188,6 +198,7 @@ that Go can provide.

 
           

           
+	        
             
           
         

     

         
@@ -32,6 +31,7 @@ of the data structures we’ve already learned.

@@ -41,6 +41,7 @@ of the data structures we’ve already learned.

 
           
           

+	        
             
           
         

             
           
           

+	        
             
package main
 

 
@@ -52,6 +53,7 @@ of the data structures we’ve already learned.

             
           		
           
+	        
             
import "fmt"
 

 
@@ -63,6 +65,7 @@ of the data structures we’ve already learned.

             
           		
           
+	        
             
func main() {
 

 
@@ -76,6 +79,7 @@ Arrays work like this too.

 
           		
           
+	        
             
    nums := []int{2, 3, 4}
     sum := 0
     for _, num := range nums {
@@ -97,6 +101,7 @@ the indexes though.

 
           

           
+	        
             
    for i, num := range nums {
         if num == 3 {
             fmt.Println("index:", i)
@@ -113,6 +118,7 @@ the indexes though.

 
           

           
+	        
             
    kvs := map[string]string{"a": "apple", "b": "banana"}
     for k, v := range kvs {
         fmt.Printf("%s -> %s\n", k, v)
@@ -130,6 +136,7 @@ of the rune and the second the rune itself.

 
           

           
+	        
             
    for i, c := range "go" {
         fmt.Println(i, c)
     }
@@ -148,6 +155,7 @@ of the rune and the second the rune itself.

             
           

           
+	        
             
$ go run range.go 
 sum: 9
 index: 1
diff --git a/public/range-over-channels b/public/range-over-channels
index 2a9cf69..202fb59 100644
--- a/public/range-over-channels
+++ b/public/range-over-channels
@@ -20,7 +20,6 @@
   
     

       
Go by Example: Range over Channels

-      
       
       
         
@@ -33,6 +32,7 @@ values received from a channel.

@@ -42,6 +42,7 @@ values received from a channel.

diff --git a/public/rate-limiting b/public/rate-limiting
index 4e50cdc..7eae4fc 100644
--- a/public/rate-limiting
+++ b/public/rate-limiting
@@ -20,7 +20,6 @@
   

       
Go by Example: Rate Limiting

-      
       
       

 
           
           

+	        
             
           
         

             
           
           

+	        
             
package main
 

 
@@ -53,6 +54,7 @@ values received from a channel.

             
           		
           
+	        
             
import "fmt"
 

 
@@ -64,6 +66,7 @@ values received from a channel.

             
           		
           
+	        
             
func main() {
 

 
@@ -76,6 +79,7 @@ values received from a channel.

 
           		
           
+	        
             
    queue := make(chan string, 2)
     queue <- "one"
     queue <- "two"
@@ -95,6 +99,7 @@ we’d block on a 3rd receive in the loop.

 
           

           
+	        
             
    for elem := range queue {
         fmt.Println(elem)
     }
@@ -113,6 +118,7 @@ we’d block on a 3rd receive in the loop.

             
           

           
+	        
             
$ go run range-over-channels.go
 one
 two
@@ -129,6 +135,7 @@ values be received.

 
           

           
+	        
             
           
         

     

         
@@ -34,6 +33,7 @@ channels, and tickers.

@@ -43,6 +43,7 @@ channels, and tickers.

 
           
           

+	        
             
           
         

             
           
           

+	        
             
package main
 

 
@@ -54,6 +55,7 @@ channels, and tickers.

             
           		
           
+	        
             
import "time"
 import "fmt"
 

@@ -66,6 +68,7 @@ channels, and tickers.

             
           		
           
+	        
             
func main() {
 

 
@@ -81,6 +84,7 @@ same name.

 
           		
           
+	        
             
    requests := make(chan int, 5)
     for i := 1; i <= 5; i++ {
         requests <- i
@@ -99,6 +103,7 @@ our rate limiting scheme.

 
           

           
+	        
             
    limiter := time.Tick(time.Millisecond * 200)
 

 
@@ -113,6 +118,7 @@ before serving each request, we limit ourselves to
 
           		
           
+	        
             
    for req := range requests {
         <-limiter
         fmt.Println("request", req, time.Now())
@@ -132,6 +138,7 @@ channel will allow bursts of up to 3 events.

 
           

           
+	        
             
    burstyLimiter := make(chan time.Time, 3)
 

 
@@ -144,6 +151,7 @@ channel will allow bursts of up to 3 events.

 
           		
           
+	        
             
    for i := 0; i < 3; i++ {
         burstyLimiter <- time.Now()
     }
@@ -159,6 +167,7 @@ value to burstyLimiter, up to its limit of 3.

 
           

           
+	        
             
    go func() {
         for t := range time.Tick(time.Millisecond * 200) {
             burstyLimiter <- t
@@ -177,6 +186,7 @@ of burstyLimiter.

 
           

           
+	        
             
    burstyRequests := make(chan int, 5)
     for i := 1; i <= 5; i++ {
         burstyRequests <- i
@@ -203,6 +213,7 @@ handled once every ~200 milliseconds as desired.

 
           

           
+	        
             
$ go run rate-limiting.go
 request 1 2012-10-19 00:38:18.687438 +0000 UTC
 request 2 2012-10-19 00:38:18.887471 +0000 UTC
@@ -222,6 +233,7 @@ then serve the remaining 2 with ~200ms delays each.

 
           

           
+	        
             
request 1 2012-10-19 00:38:20.487578 +0000 UTC
 request 2 2012-10-19 00:38:20.487645 +0000 UTC
 request 3 2012-10-19 00:38:20.487676 +0000 UTC
diff --git a/public/reading-files b/public/reading-files
index b946860..f491aff 100644
--- a/public/reading-files
+++ b/public/reading-files
@@ -20,7 +20,6 @@
   
     

       
Go by Example: Reading Files

-      
       
       
         
@@ -32,6 +31,7 @@ reading files.

@@ -41,6 +41,7 @@ reading files.

diff --git a/public/recursion b/public/recursion
index 516faa2..295fad2 100644
--- a/public/recursion
+++ b/public/recursion
@@ -20,7 +20,6 @@
   

       
Go by Example: Recursion

-      
       
       

 
           
           

+	        
             
           
         

             
           
           

+	        
             
package main
 

 
@@ -52,6 +53,7 @@ reading files.

             
           		
           
+	        
             
import (
     "bufio"
     "fmt"
@@ -71,6 +73,7 @@ This helper will streamline our error checks below.

 
           

           
+	        
             
func check(e error) {
     if e != nil {
         panic(e)
@@ -86,6 +89,7 @@ This helper will streamline our error checks below.

             
           

           
+	        
             
func main() {
 

 
@@ -99,6 +103,7 @@ slurping a file’s entire contents into memory.

 
           		
           
+	        
             
    dat, err := ioutil.ReadFile("/tmp/dat")
     check(err)
     fmt.Print(string(dat))
@@ -115,6 +120,7 @@ by Opening a file to obtain an os.File value.

 
           

           
+	        
             
    f, err := os.Open("/tmp/dat")
 

 
@@ -129,6 +135,7 @@ actually were read.

 
           		
           
+	        
             
    b1 := make([]byte, 5)
     n1, err := f.Read(b1)
     check(err)
@@ -145,6 +152,7 @@ and Read from there.

 
           

           
+	        
             
    o2, err := f.Seek(6, 0)
     check(err)
     b2 := make([]byte, 2)
@@ -165,6 +173,7 @@ implemented with ReadAtLeast.

 
           

           
+	        
             
    o3, err := f.Seek(6, 0)
     check(err)
     b3 := make([]byte, 2)
@@ -183,6 +192,7 @@ accomplishes this.

 
           

           
+	        
             
    _, err = f.Seek(0, 0)
     check(err)
 

@@ -199,6 +209,7 @@ reading methods it provides.

 
           		
           
+	        
             
    r4 := bufio.NewReader(f)
     b4, err := r4.Peek(5)
     check(err)
@@ -216,6 +227,7 @@ be scheduled immediately after Opening with
 
           

           
+	        
             
    f.Close()
 

 
@@ -227,6 +239,7 @@ be scheduled immediately after Opening with
             
           		
           
+	        
             
}
 

 
@@ -242,6 +255,7 @@ be scheduled immediately after Opening with
             
           		
           
+	        
             
$ echo "hello" > /tmp/dat
 $ echo "go" >>   /tmp/dat
 $ go run reading-files.go 
@@ -262,6 +276,7 @@ be scheduled immediately after Opening with
 
           

           
+	        
             
           
         

     

         
@@ -32,6 +31,7 @@ Here’s a classic factorial example.

@@ -41,6 +41,7 @@ Here’s a classic factorial example.

 
           
           

+	        
             
           
         

             
           
           

+	        
             
package main
 

 
@@ -52,6 +53,7 @@ Here’s a classic factorial example.

             
           		
           
+	        
             
import "fmt"
 

 
@@ -65,6 +67,7 @@ base case of fact(0).

 
           		
           
+	        
             
func fact(n int) int {
     if n == 0 {
         return 1
@@ -81,6 +84,7 @@ base case of fact(0).

             
           

           
+	        
             
func main() {
     fmt.Println(fact(7))
 }
@@ -98,6 +102,7 @@ base case of fact(0).

             
           

           
+	        
             
$ go run recursion.go 
 5040
 

diff --git a/public/regular-expressions b/public/regular-expressions
index ca8a19f..dd9af01 100644
--- a/public/regular-expressions
+++ b/public/regular-expressions
@@ -20,7 +20,6 @@
   
     

       
Go by Example: Regular Expressions

-      
       
       
         
@@ -32,6 +31,7 @@ in Go.

@@ -41,6 +41,7 @@ in Go.

diff --git a/public/select b/public/select
index c4d94c9..33e0bcf 100644
--- a/public/select
+++ b/public/select
@@ -20,7 +20,6 @@
   

       
Go by Example: Select

-      
       
       

 
           
           

+	        
             
           
         

             
           
           

+	        
             
package main
 

 
@@ -52,6 +53,7 @@ in Go.

             
           		
           
+	        
             
import "bytes"
 import "fmt"
 import "regexp"
@@ -65,6 +67,7 @@ in Go.

             
           

           
+	        
             
func main() {
 

 
@@ -77,6 +80,7 @@ in Go.

 
           		
           
+	        
             
    match, _ := regexp.MatchString("p([a-z]+)ch", "peach")
     fmt.Println(match)
 

@@ -92,6 +96,7 @@ optimized Regexp struct.

 
           		
           
+	        
             
    r, _ := regexp.Compile("p([a-z]+)ch")
 

 
@@ -105,6 +110,7 @@ a match test like we saw earlier.

 
           		
           
+	        
             
    fmt.Println(r.MatchString("peach"))
 

 
@@ -117,6 +123,7 @@ a match test like we saw earlier.

 
           		
           
+	        
             
    fmt.Println(r.FindString("peach punch"))
 

 
@@ -131,6 +138,7 @@ matching text.

 
           		
           
+	        
             
    fmt.Println(r.FindStringIndex("peach punch"))
 

 
@@ -146,6 +154,7 @@ information for both p([a-z]+)ch and ([a-z]+).

 
           		
           
+	        
             
    fmt.Println(r.FindStringSubmatch("peach punch"))
 

 
@@ -159,6 +168,7 @@ indexes of matches and submatches.

 
           		
           
+	        
             
    fmt.Println(r.FindStringSubmatchIndex("peach punch"))
 

 
@@ -173,6 +183,7 @@ example to find all matches for a regexp.

 
           		
           
+	        
             
    fmt.Println(r.FindAllString("peach punch pinch", -1))
 

 
@@ -186,6 +197,7 @@ functions we saw above as well.

 
           		
           
+	        
             
    fmt.Println(r.FindAllStringSubmatchIndex(
         "peach punch pinch", -1))
 

@@ -201,6 +213,7 @@ of matches.

 
           		
           
+	        
             
    fmt.Println(r.FindAllString("peach punch pinch", 2))
 

 
@@ -216,6 +229,7 @@ function name.

 
           		
           
+	        
             
    fmt.Println(r.Match([]byte("peach")))
 

 
@@ -231,6 +245,7 @@ constants because it has 2 return values.

 
           		
           
+	        
             
    r = regexp.MustCompile("p([a-z]+)ch")
     fmt.Println(r)
 

@@ -245,6 +260,7 @@ subsets of strings with other values.

 
           		
           
+	        
             
    fmt.Println(r.ReplaceAllString("a peach", "<fruit>"))
 

 
@@ -258,6 +274,7 @@ text with a given function.

 
           		
           
+	        
             
    in := []byte("a peach")
     out := r.ReplaceAllFunc(in, bytes.ToUpper)
     fmt.Println(string(out))
@@ -276,6 +293,7 @@ text with a given function.

             
           

           
+	        
             
$ go run regular-expressions.go 
 true
 true
@@ -302,6 +320,7 @@ the regexp package docs
 
           

           
+	        
             
           
         

     

         
@@ -32,6 +31,7 @@ select is powerful feature of Go.

@@ -41,6 +41,7 @@ select is powerful feature of Go.

 
           
           

+	        
             
           
         

             
           
           

+	        
             
package main
 

 
@@ -52,6 +53,7 @@ select is powerful feature of Go.

             
           		
           
+	        
             
import "time"
 import "fmt"
 

@@ -64,6 +66,7 @@ select is powerful feature of Go.

             
           		
           
+	        
             
func main() {
 

 
@@ -76,6 +79,7 @@ select is powerful feature of Go.

 
           		
           
+	        
             
    c1 := make(chan string)
     c2 := make(chan string)
 

@@ -91,6 +95,7 @@ executing in concurrent goroutines.

 
           		
           
+	        
             
    go func() {
         time.Sleep(time.Second * 1)
         c1 <- "one"
@@ -111,6 +116,7 @@ simultaneously, printing each one as it arrives.

 
           

           
+	        
             
    for i := 0; i < 2; i++ {
         select {
         case msg1 := <-c1:
@@ -136,6 +142,7 @@ expected.

 
           

           
+	        
             
$ time go run select.go 
 received one
 received two
@@ -152,6 +159,7 @@ concurrently.

 
           

           
+	        
             
real	0m2.245s
 

 
diff --git a/public/sha1-hashes b/public/sha1-hashes
index 0d0e1a9..285c703 100644
--- a/public/sha1-hashes
+++ b/public/sha1-hashes
@@ -20,7 +20,6 @@
   
     

       
Go by Example: SHA1 Hashes

-      
       
       
         
@@ -35,6 +34,7 @@ compute SHA1 hashes in Go.

@@ -44,6 +44,7 @@ compute SHA1 hashes in Go.

@@ -172,6 +181,7 @@ you should carefully research
 
           
diff --git a/public/signals b/public/signals
index 5ed5dbc..a149a0e 100644
--- a/public/signals
+++ b/public/signals
@@ -20,7 +20,6 @@
   

       
Go by Example: Signals

-      
       
       

 
           
           

+	        
             
           
         

             
           
           

+	        
             
package main
 

 
@@ -57,6 +58,7 @@ compute SHA1 hashes in Go.

 
           		
           
+	        
             
import "crypto/sha1"
 import "fmt"
 

@@ -69,6 +71,7 @@ compute SHA1 hashes in Go.

             
           		
           
+	        
             
func main() {
     s := "sha1 this string"
 

@@ -84,6 +87,7 @@ Here we start with a new hash.

 
           		
           
+	        
             
    h := sha1.New()
 

 
@@ -97,6 +101,7 @@ use []byte(s) to coerce it to bytes.

 
           		
           
+	        
             
    h.Write([]byte(s))
 

 
@@ -111,6 +116,7 @@ to an existing byte slice: it usually isn’t needed.

 
           		
           
+	        
             
    bs := h.Sum(nil)
 

 
@@ -125,6 +131,7 @@ a hash results to a hex string.

 
           		
           
+	        
             
    fmt.Println(s)
     fmt.Printf("%x\n", bs)
 }
@@ -144,6 +151,7 @@ a human-readable hex format.

 
           

           
+	        
             
$ go run sha1-hashes.go
 sha1 this string
 cf23df2207d99a74fbe169e3eba035e633b65d94
@@ -160,6 +168,7 @@ import crypto/md5 and use md5.New().

 
           

           
+	        
             
           
         

           

+	        
             
           
         

     

         
@@ -35,6 +34,7 @@ Here’s how to handle signals in Go with channels.

@@ -44,6 +44,7 @@ Here’s how to handle signals in Go with channels.

 
           
           

+	        
             
           
         

             
           
           

+	        
             
package main
 

 
@@ -55,6 +56,7 @@ Here’s how to handle signals in Go with channels.

             
           		
           
+	        
             
import "fmt"
 import "os"
 import "os/signal"
@@ -69,6 +71,7 @@ Here’s how to handle signals in Go with channels.

             
           

           
+	        
             
func main() {
 

 
@@ -84,6 +87,7 @@ notify us when the program can exit.)

 
           		
           
+	        
             
    sigs := make(chan os.Signal, 1)
     done := make(chan bool, 1)
 

@@ -98,6 +102,7 @@ receive notifications of the specified signals.

 
           		
           
+	        
             
    signal.Notify(sigs, syscall.SIGINT, syscall.SIGTERM)
 

 
@@ -112,6 +117,7 @@ and then notify the program that it can finish.

 
           		
           
+	        
             
    go func() {
         sig := <-sigs
         fmt.Println()
@@ -131,6 +137,7 @@ above sending a value on done) and then exit.

 
           

           
+	        
             
    fmt.Println("awaiting signal")
     <-done
     fmt.Println("exiting")
@@ -153,6 +160,7 @@ causing the program to print interrupt and then exit.

 
           

           
+	        
             
$ go run signals.go
 awaiting signal
 ^C
diff --git a/public/slices b/public/slices
index 0f282ec..e69b209 100644
--- a/public/slices
+++ b/public/slices
@@ -20,7 +20,6 @@
   
     

       
Go by Example: Slices

-      
       
       
         
@@ -31,6 +30,7 @@ powerful interface to sequences than arrays.

@@ -40,6 +40,7 @@ powerful interface to sequences than arrays.

@@ -273,6 +288,7 @@ Go’s other key builtin data structure: maps.

diff --git a/public/sorting b/public/sorting
index bd380b1..31dd745 100644
--- a/public/sorting
+++ b/public/sorting
@@ -20,7 +20,6 @@
   

       
Go by Example: Sorting

-      
       
       

 
           
           

+	        
             
           
         

             
           
           

+	        
             
package main
 

 
@@ -51,6 +52,7 @@ powerful interface to sequences than arrays.

             
           		
           
+	        
             
import "fmt"
 

 
@@ -62,6 +64,7 @@ powerful interface to sequences than arrays.

             
           		
           
+	        
             
func main() {
 

 
@@ -78,6 +81,7 @@ the builtin make. Here we make a slice of
 
           		
           
+	        
             
    s := make([]string, 3)
     fmt.Println("emp:", s)
 

@@ -91,6 +95,7 @@ the builtin make. Here we make a slice of
 
           		
           
+	        
             
    s[0] = "a"
     s[1] = "b"
     s[2] = "c"
@@ -107,6 +112,7 @@ the builtin make. Here we make a slice of
 
           

           
+	        
             
    fmt.Println("len:", len(s))
 

 
@@ -124,6 +130,7 @@ append as we may get a new slice value.

 
           		
           
+	        
             
    s = append(s, "d")
     s = append(s, "e", "f")
     fmt.Println("apd:", s)
@@ -140,6 +147,7 @@ into c from s.

 
           

           
+	        
             
    c := make([]string, len(s))
     copy(c, s)
     fmt.Println("cpy:", c)
@@ -156,6 +164,7 @@ of the elements s[2], s[3], and s[4].

 
           

           
+	        
             
    l := s[2:5]
     fmt.Println("sl1:", l)
 

@@ -169,6 +178,7 @@ of the elements s[2], s[3], and s[4].

 
           		
           
+	        
             
    l = s[:5]
     fmt.Println("sl2:", l)
 

@@ -182,6 +192,7 @@ of the elements s[2], s[3], and s[4].

 
           		
           
+	        
             
    l = s[2:]
     fmt.Println("sl3:", l)
 

@@ -196,6 +207,7 @@ in a single line as well.

 
           		
           
+	        
             
    t := []string{"g", "h", "i"}
     fmt.Println("dcl:", t)
 

@@ -211,6 +223,7 @@ vary, unlike with multi-dimensional arrays.

 
           		
           
+	        
             
    twoD := make([][]int, 3)
     for i := 0; i < 3; i++ {
         innerLen := i + 1
@@ -237,6 +250,7 @@ they are rendered similarly by fmt.Println.

 
           

           
+	        
             
$ go run slices.go
 emp: [  ]
 set: [a b c]
@@ -262,6 +276,7 @@ implementation of slices in Go.

 
           

           
+	        
             
           
         

 
           
           

+	        
             
           
         

     

         
@@ -32,6 +31,7 @@ builtins first.

@@ -41,6 +41,7 @@ builtins first.

 
           
           

+	        
             
           
         

             
           
           

+	        
             
package main
 

 
@@ -52,6 +53,7 @@ builtins first.

             
           		
           
+	        
             
import "fmt"
 import "sort"
 

@@ -64,6 +66,7 @@ builtins first.

             
           		
           
+	        
             
func main() {
 

 
@@ -79,6 +82,7 @@ return a new one.

 
           		
           
+	        
             
    strs := []string{"c", "a", "b"}
     sort.Strings(strs)
     fmt.Println("Strings:", strs)
@@ -93,6 +97,7 @@ return a new one.

 
           

           
+	        
             
    ints := []int{7, 2, 4}
     sort.Ints(ints)
     fmt.Println("Ints:   ", ints)
@@ -108,6 +113,7 @@ already in sorted order.

 
           

           
+	        
             
    s := sort.IntsAreSorted(ints)
     fmt.Println("Sorted: ", s)
 }
@@ -127,6 +133,7 @@ slices and true as the result of our AreSorted test.
           

+	        
             
$ go run sorting.go
 Strings: [a b c]
 Ints:    [2 4 7]
diff --git a/public/sorting-by-functions b/public/sorting-by-functions
index 4b01d4f..85af568 100644
--- a/public/sorting-by-functions
+++ b/public/sorting-by-functions
@@ -20,7 +20,6 @@
   
     

       
Go by Example: Sorting by Functions

-      
       
       
         
@@ -34,6 +33,7 @@ in Go.

@@ -43,6 +43,7 @@ in Go.

diff --git a/public/spawning-processes b/public/spawning-processes
index 8279f46..a6d4da7 100644
--- a/public/spawning-processes
+++ b/public/spawning-processes
@@ -20,7 +20,6 @@
   

       
Go by Example: Spawning Processes

-      
       
       

 
           
           

+	        
             
           
         

             
           
           

+	        
             
package main
 

 
@@ -54,6 +55,7 @@ in Go.

             
           		
           
+	        
             
import "sort"
 import "fmt"
 

@@ -70,6 +72,7 @@ type.

 
           		
           
+	        
             
type ByLength []string
 

 
@@ -88,6 +91,7 @@ we use len(s[i]) and len(s[j]) here.

 
           		
           
+	        
             
func (s ByLength) Len() int {
     return len(s)
 }
@@ -111,6 +115,7 @@ slice.

 
           

           
+	        
             
func main() {
     fruits := []string{"peach", "banana", "kiwi"}
     sort.Sort(ByLength(fruits))
@@ -132,6 +137,7 @@ length, as desired.

 
           

           
+	        
             
$ go run sorting-by-functions.go 
 [kiwi peach banana]
 

@@ -149,6 +155,7 @@ functions.

 
           		
           
+	        
             
           
         

     

         
@@ -35,6 +34,7 @@ of spawning processes from Go.

@@ -44,6 +44,7 @@ of spawning processes from Go.

 
           
           

+	        
             
           
         

             
           
           

+	        
             
package main
 

 
@@ -55,6 +56,7 @@ of spawning processes from Go.

             
           		
           
+	        
             
import "fmt"
 import "io/ioutil"
 import "os/exec"
@@ -68,6 +70,7 @@ of spawning processes from Go.

             
           

           
+	        
             
func main() {
 

 
@@ -83,6 +86,7 @@ to represent this external process.

 
           		
           
+	        
             
    dateCmd := exec.Command("date")
 

 
@@ -98,6 +102,7 @@ and collecting its output. If there were no errors,
 
           		
           
+	        
             
    dateOut, err := dateCmd.Output()
     if err != nil {
         panic(err)
@@ -117,6 +122,7 @@ where we pipe data to the external process on its
 
           

           
+	        
             
    grepCmd := exec.Command("grep", "hello")
 

 
@@ -132,6 +138,7 @@ to exit.

 
           		
           
+	        
             
    grepIn, _ := grepCmd.StdinPipe()
     grepOut, _ := grepCmd.StdoutPipe()
     grepCmd.Start()
@@ -154,6 +161,7 @@ exactly the same way.

 
           

           
+	        
             
    fmt.Println("> grep hello")
     fmt.Println(string(grepBytes))
 

@@ -172,6 +180,7 @@ option:

 
           		
           
+	        
             
    lsCmd := exec.Command("bash", "-c", "ls -a -l -h")
     lsOut, err := lsCmd.Output()
     if err != nil {
@@ -196,6 +205,7 @@ as if we had run them directly from the command-line.

 
           

           
+	        
             
$ go run spawning-processes.go 
 > date
 Wed Oct 10 09:53:11 PDT 2012
@@ -209,6 +219,7 @@ as if we had run them directly from the command-line.

             
           

           
+	        
             
> grep hello
 hello grep
 

@@ -221,6 +232,7 @@ as if we had run them directly from the command-line.

             
           		
           
+	        
             
> ls -a -l -h
 drwxr-xr-x  4 mark 136B Oct 3 16:29 .
 drwxr-xr-x 91 mark 3.0K Oct 3 12:50 ..
diff --git a/public/stateful-goroutines b/public/stateful-goroutines
index 03b2626..485ec2f 100644
--- a/public/stateful-goroutines
+++ b/public/stateful-goroutines
@@ -20,7 +20,6 @@
   
     

       
Go by Example: Stateful Goroutines

-      
       
       
         
@@ -37,6 +36,7 @@ by exactly 1 goroutine.

@@ -46,6 +46,7 @@ by exactly 1 goroutine.

diff --git a/public/string-formatting b/public/string-formatting
index 015b4df..9e54b0a 100644
--- a/public/string-formatting
+++ b/public/string-formatting
@@ -20,7 +20,6 @@
   

       
Go by Example: String Formatting

-      
       
       

 
           
           

+	        
             
           
         

             
           
           

+	        
             
package main
 

 
@@ -57,6 +58,7 @@ by exactly 1 goroutine.

             
           		
           
+	        
             
import (
     "fmt"
     "math/rand"
@@ -81,6 +83,7 @@ goroutine to respond.

 
           

           
+	        
             
type readOp struct {
     key  int
     resp chan int
@@ -100,6 +103,7 @@ goroutine to respond.

             
           

           
+	        
             
func main() {
 

 
@@ -113,6 +117,7 @@ example.

 
           		
           
+	        
             
    var state = make(map[int]int)
 

 
@@ -126,6 +131,7 @@ perform.

 
           		
           
+	        
             
    var ops int64 = 0
 

 
@@ -140,6 +146,7 @@ respectively.

 
           		
           
+	        
             
    reads := make(chan *readOp)
     writes := make(chan *writeOp)
 

@@ -159,6 +166,7 @@ on the response channel resp to indicate success
 
           		
           
+	        
             
    go func() {
         for {
             select {
@@ -185,6 +193,7 @@ result over the provided resp channel.

 
           

           
+	        
             
    for r := 0; r < 100; r++ {
         go func() {
             for {
@@ -209,6 +218,7 @@ approach.

 
           

           
+	        
             
    for w := 0; w < 10; w++ {
         go func() {
             for {
@@ -233,6 +243,7 @@ approach.

 
           

           
+	        
             
    time.Sleep(time.Second)
 

 
@@ -245,6 +256,7 @@ approach.

 
           		
           
+	        
             
    opsFinal := atomic.LoadInt64(&ops)
     fmt.Println("ops:", opsFinal)
 }
@@ -265,6 +277,7 @@ operations per second.

 
           

           
+	        
             
$ go run stateful-goroutines.go
 ops: 807434
 

@@ -285,6 +298,7 @@ program.

 
           		
           
+	        
             
           
         

     

         
@@ -32,6 +31,7 @@ common string formatting tasks.

@@ -41,6 +41,7 @@ common string formatting tasks.

 
           
           

+	        
             
           
         

             
           
           

+	        
             
package main
 

 
@@ -52,6 +53,7 @@ common string formatting tasks.

             
           		
           
+	        
             
import "fmt"
 import "os"
 

@@ -64,6 +66,7 @@ common string formatting tasks.

             
           		
           
+	        
             
type point struct {
     x, y int
 }
@@ -77,6 +80,7 @@ common string formatting tasks.

             
           

           
+	        
             
func main() {
 

 
@@ -91,6 +95,7 @@ an instance of our point struct.

 
           		
           
+	        
             
    p := point{1, 2}
     fmt.Printf("%v\n", p)
 

@@ -105,6 +110,7 @@ include the struct’s field names.

 
           		
           
+	        
             
    fmt.Printf("%+v\n", p)
 

 
@@ -119,6 +125,7 @@ would produce that value.

 
           		
           
+	        
             
    fmt.Printf("%#v\n", p)
 

 
@@ -131,6 +138,7 @@ would produce that value.

 
           		
           
+	        
             
    fmt.Printf("%T\n", p)
 

 
@@ -143,6 +151,7 @@ would produce that value.

 
           		
           
+	        
             
    fmt.Printf("%t\n", true)
 

 
@@ -156,6 +165,7 @@ Use %d for standard, base-10 formatting.

 
           		
           
+	        
             
    fmt.Printf("%d\n", 123)
 

 
@@ -168,6 +178,7 @@ Use %d for standard, base-10 formatting.

 
           		
           
+	        
             
    fmt.Printf("%b\n", 14)
 

 
@@ -181,6 +192,7 @@ given integer.

 
           		
           
+	        
             
    fmt.Printf("%c\n", 33)
 

 
@@ -193,6 +205,7 @@ given integer.

 
           		
           
+	        
             
    fmt.Printf("%x\n", 456)
 

 
@@ -206,6 +219,7 @@ floats. For basic decimal formatting use %f.

 
           		
           
+	        
             
    fmt.Printf("%f\n", 78.9)
 

 
@@ -219,6 +233,7 @@ different versions of) scientific notation.

 
           		
           
+	        
             
    fmt.Printf("%e\n", 123400000.0)
     fmt.Printf("%E\n", 123400000.0)
 

@@ -232,6 +247,7 @@ different versions of) scientific notation.

 
           		
           
+	        
             
    fmt.Printf("%s\n", "\"string\"")
 

 
@@ -244,6 +260,7 @@ different versions of) scientific notation.

 
           		
           
+	        
             
    fmt.Printf("%q\n", "\"string\"")
 

 
@@ -258,6 +275,7 @@ per byte of input.

 
           		
           
+	        
             
    fmt.Printf("%x\n", "hex this")
 

 
@@ -270,6 +288,7 @@ per byte of input.

 
           		
           
+	        
             
    fmt.Printf("%p\n", &p)
 

 
@@ -287,6 +306,7 @@ spaces.

 
           		
           
+	        
             
    fmt.Printf("|%6d|%6d|\n", 12, 345)
 

 
@@ -302,6 +322,7 @@ width.precision syntax.

 
           		
           
+	        
             
    fmt.Printf("|%6.2f|%6.2f|\n", 1.2, 3.45)
 

 
@@ -314,6 +335,7 @@ width.precision syntax.

 
           		
           
+	        
             
    fmt.Printf("|%-6.2f|%-6.2f|\n", 1.2, 3.45)
 

 
@@ -328,6 +350,7 @@ table-like output. For basic right-justified width.

 
           		
           
+	        
             
    fmt.Printf("|%6s|%6s|\n", "foo", "b")
 

 
@@ -340,6 +363,7 @@ table-like output. For basic right-justified width.

 
           		
           
+	        
             
    fmt.Printf("|%-6s|%-6s|\n", "foo", "b")
 

 
@@ -354,6 +378,7 @@ and returns a string without printing it anywhere.

 
           		
           
+	        
             
    s := fmt.Sprintf("a %s", "string")
     fmt.Println(s)
 

@@ -368,6 +393,7 @@ and returns a string without printing it anywhere.

 
           		
           
+	        
             
    fmt.Fprintf(os.Stderr, "an %s\n", "error")
 }
 

@@ -384,6 +410,7 @@ and returns a string without printing it anywhere.

             
           		
           
+	        
             
$ go run string-formatting.go
 {1 2}
 {x:1 y:2}
diff --git a/public/string-functions b/public/string-functions
index 5fe25ce..6b83df4 100644
--- a/public/string-functions
+++ b/public/string-functions
@@ -20,7 +20,6 @@
   
     

       
Go by Example: String Functions

-      
       
       
         
@@ -32,6 +31,7 @@ to give you a sense of the package.

@@ -41,6 +41,7 @@ to give you a sense of the package.

@@ -130,6 +136,7 @@ and getting a character by index.

 
           
           

+	        
             
           
         

             
           
           

+	        
             
package main
 

 
@@ -52,6 +53,7 @@ to give you a sense of the package.

             
           		
           
+	        
             
import s "strings"
 import "fmt"
 

@@ -66,6 +68,7 @@ it a lot below.

 
           		
           
+	        
             
var p = fmt.Println
 

 
@@ -77,6 +80,7 @@ it a lot below.

             
           		
           
+	        
             
func main() {
 

 
@@ -93,6 +97,7 @@ as the first argument to the function.

 
           		
           
+	        
             
    p("Contains:  ", s.Contains("test", "es"))
     p("Count:     ", s.Count("test", "t"))
     p("HasPrefix: ", s.HasPrefix("test", "te"))
@@ -118,6 +123,7 @@ package docs.

 
           

           
+	        
             
           
         

 
           
           

+	        
             
    p("Len: ", len("hello"))
     p("Char:", "hello"[1])
 }
@@ -147,6 +154,7 @@ and getting a character by index.

             
           

           
+	        
             
$ go run string-functions.go
 Contains:   true
 Count:      2
@@ -170,6 +178,7 @@ and getting a character by index.

             
           

           
+	        
             
Len:  5
 Char: 101
 

diff --git a/public/structs b/public/structs
index 34dfc36..7b41cd5 100644
--- a/public/structs
+++ b/public/structs
@@ -20,7 +20,6 @@
   
     

       
Go by Example: Structs

-      
       
       
         
@@ -32,6 +31,7 @@ records.

@@ -41,6 +41,7 @@ records.

 
           
           

+	        
             
           
         

             
           
           

+	        
             
package main
 

 
@@ -52,6 +53,7 @@ records.

             
           		
           
+	        
             
import "fmt"
 

 
@@ -64,6 +66,7 @@ records.

 
           		
           
+	        
             
type person struct {
     name string
     age  int
@@ -78,6 +81,7 @@ records.

             
           

           
+	        
             
func main() {
 

 
@@ -90,6 +94,7 @@ records.

 
           		
           
+	        
             
    fmt.Println(person{"Bob", 20})
 

 
@@ -102,6 +107,7 @@ records.

 
           		
           
+	        
             
    fmt.Println(person{name: "Alice", age: 30})
 

 
@@ -114,6 +120,7 @@ records.

 
           		
           
+	        
             
    fmt.Println(person{name: "Fred"})
 

 
@@ -126,6 +133,7 @@ records.

 
           		
           
+	        
             
    fmt.Println(&person{name: "Ann", age: 40})
 

 
@@ -138,6 +146,7 @@ records.

 
           		
           
+	        
             
    s := person{name: "Sean", age: 50}
     fmt.Println(s.name)
 

@@ -152,6 +161,7 @@ pointers are automatically dereferenced.

 
           		
           
+	        
             
    sp := &s
     fmt.Println(sp.age)
 

@@ -165,6 +175,7 @@ pointers are automatically dereferenced.

 
           		
           
+	        
             
    sp.age = 51
     fmt.Println(sp.age)
 }
@@ -182,6 +193,7 @@ pointers are automatically dereferenced.

             
           

           
+	        
             
$ go run structs.go
 {Bob 20}
 {Alice 30}
diff --git a/public/switch b/public/switch
index e51eb62..f999571 100644
--- a/public/switch
+++ b/public/switch
@@ -20,7 +20,6 @@
   
     

       
Go by Example: Switch

-      
       
       
         
@@ -31,6 +30,7 @@ branches.

@@ -40,6 +40,7 @@ branches.

 
           
           

+	        
             
           
         

             
           
           

+	        
             
package main
 

 
@@ -51,6 +52,7 @@ branches.

             
           		
           
+	        
             
import "fmt"
 import "time"
 

@@ -63,6 +65,7 @@ branches.

             
           		
           
+	        
             
func main() {
 

 
@@ -75,6 +78,7 @@ branches.

 
           		
           
+	        
             
    i := 2
     fmt.Print("write ", i, " as ")
     switch i {
@@ -98,6 +102,7 @@ in the same case statement. We use the optional
 
           

           
+	        
             
    switch time.Now().Weekday() {
     case time.Saturday, time.Sunday:
         fmt.Println("it's the weekend")
@@ -117,6 +122,7 @@ to express if/else logic. Here we also show how the
 
           

           
+	        
             
    t := time.Now()
     switch {
     case t.Hour() < 12:
@@ -139,6 +145,7 @@ to express if/else logic. Here we also show how the
             
           

           
+	        
             
$ go run switch.go 
 write 2 as two
 it's the weekend
diff --git a/public/tickers b/public/tickers
index 7c33751..48fd574 100644
--- a/public/tickers
+++ b/public/tickers
@@ -20,7 +20,6 @@
   
     

       
Go by Example: Tickers

-      
       
       
         
@@ -34,6 +33,7 @@ periodically until we stop it.

@@ -43,6 +43,7 @@ periodically until we stop it.

 
           
           

+	        
             
           
         

             
           
           

+	        
             
package main
 

 
@@ -54,6 +55,7 @@ periodically until we stop it.

             
           		
           
+	        
             
import "time"
 import "fmt"
 

@@ -66,6 +68,7 @@ periodically until we stop it.

             
           		
           
+	        
             
func main() {
 

 
@@ -81,6 +84,7 @@ the values as they arrive every 500ms.

 
           		
           
+	        
             
    ticker := time.NewTicker(time.Millisecond * 500)
     go func() {
         for t := range ticker.C {
@@ -100,6 +104,7 @@ channel. We’ll stop ours after 1500ms.

 
           

           
+	        
             
    time.Sleep(time.Millisecond * 1500)
     ticker.Stop()
     fmt.Println("Ticker stopped")
@@ -120,6 +125,7 @@ before we stop it.

 
           

           
+	        
             
$ go run tickers.go
 Tick at 2012-09-23 11:29:56.487625 -0700 PDT
 Tick at 2012-09-23 11:29:56.988063 -0700 PDT
diff --git a/public/time b/public/time
index ec48522..76eb47c 100644
--- a/public/time
+++ b/public/time
@@ -20,7 +20,6 @@
   
     

       
Go by Example: Time

-      
       
       
         
@@ -31,6 +30,7 @@ here are some examples.

@@ -40,6 +40,7 @@ here are some examples.

diff --git a/public/time-formatting-parsing b/public/time-formatting-parsing
index 41edb34..73cc45b 100644
--- a/public/time-formatting-parsing
+++ b/public/time-formatting-parsing
@@ -20,7 +20,6 @@
   

       
Go by Example: Time Formatting / Parsing

-      
       
       

 
           
           

+	        
             
           
         

             
           
           

+	        
             
package main
 

 
@@ -51,6 +52,7 @@ here are some examples.

             
           		
           
+	        
             
import "fmt"
 import "time"
 

@@ -63,6 +65,7 @@ here are some examples.

             
           		
           
+	        
             
func main() {
     p := fmt.Println
 

@@ -76,6 +79,7 @@ here are some examples.

 
           		
           
+	        
             
    now := time.Now()
     p(now)
 

@@ -91,6 +95,7 @@ with a Location, i.e. time zone.

 
           		
           
+	        
             
    then := time.Date(
         2009, 11, 17, 20, 34, 58, 651387237, time.UTC)
     p(then)
@@ -106,6 +111,7 @@ value as expected.

 
           

           
+	        
             
    p(then.Year())
     p(then.Month())
     p(then.Day())
@@ -125,6 +131,7 @@ value as expected.

 
           

           
+	        
             
    p(then.Weekday())
 

 
@@ -139,6 +146,7 @@ as the second, respectively.

 
           		
           
+	        
             
    p(then.Before(now))
     p(then.After(now))
     p(then.Equal(now))
@@ -154,6 +162,7 @@ the interval between two times.

 
           

           
+	        
             
    diff := now.Sub(then)
     p(diff)
 

@@ -168,6 +177,7 @@ various units.

 
           		
           
+	        
             
    p(diff.Hours())
     p(diff.Minutes())
     p(diff.Seconds())
@@ -185,6 +195,7 @@ duration.

 
           

           
+	        
             
    p(then.Add(diff))
     p(then.Add(-diff))
 }
@@ -202,6 +213,7 @@ duration.

             
           

           
+	        
             
$ go run time.go
 2012-10-31 15:50:13.793654 +0000 UTC
 2009-11-17 20:34:58.651387237 +0000 UTC
@@ -236,6 +248,7 @@ the Unix epoch.

 
           

           
+	        
             
           
         

     

         
@@ -31,6 +30,7 @@ pattern-based layouts.

@@ -40,6 +40,7 @@ pattern-based layouts.

 
           
           

+	        
             
           
         

             
           
           

+	        
             
package main
 

 
@@ -51,6 +52,7 @@ pattern-based layouts.

             
           		
           
+	        
             
import "fmt"
 import "time"
 

@@ -63,6 +65,7 @@ pattern-based layouts.

             
           		
           
+	        
             
func main() {
     p := fmt.Println
 

@@ -77,6 +80,7 @@ according to RFC3339.

 
           		
           
+	        
             
    t := time.Now()
     p(t.Format("2006-01-02T15:04:05Z07:00"))
 

@@ -95,6 +99,7 @@ formatting.

 
           		
           
+	        
             
    p(t.Format("3:04PM"))
     p(t.Format("Mon Jan _2 15:04:05 2006"))
     p(t.Format("2006-01-02T15:04:05.999999-07:00"))
@@ -111,6 +116,7 @@ components of the time value.

 
           

           
+	        
             
    fmt.Printf("%d-%02d-%02dT%02d:%02d:%02d-00:00\n",
         t.Year(), t.Month(), t.Day(),
         t.Hour(), t.Minute(), t.Second())
@@ -127,6 +133,7 @@ with some of the layouts used above.

 
           

           
+	        
             
    withNanos := "2006-01-02T15:04:05.999999999-07:00"
     t1, e := time.Parse(
         withNanos,
@@ -147,6 +154,7 @@ explaining the parsing problem.

 
           

           
+	        
             
    ansic := "Mon Jan _2 15:04:05 2006"
     _, e = time.Parse(ansic, "8:41PM")
     p(e)
@@ -162,6 +170,7 @@ use for both formatting and parsing.

 
           

           
+	        
             
    p(t.Format(time.Kitchen))
 }
 

@@ -178,6 +187,7 @@ use for both formatting and parsing.

             
           		
           
+	        
             
$ go run time-formatting-parsing.go 
 2012-11-02T09:35:03-07:00
 9:35AM
diff --git a/public/timeouts b/public/timeouts
index 7a0f185..e8b6567 100644
--- a/public/timeouts
+++ b/public/timeouts
@@ -20,7 +20,6 @@
   
     

       
Go by Example: Timeouts

-      
       
       
         
@@ -33,6 +32,7 @@ elegant thanks to channels and select.

@@ -42,6 +42,7 @@ elegant thanks to channels and select.

diff --git a/public/timers b/public/timers
index e161537..77aec09 100644
--- a/public/timers
+++ b/public/timers
@@ -20,7 +20,6 @@
   

       
Go by Example: Timers

-      
       
       

 
           
           

+	        
             
           
         

             
           
           

+	        
             
package main
 

 
@@ -53,6 +54,7 @@ elegant thanks to channels and select.

             
           		
           
+	        
             
import "time"
 import "fmt"
 

@@ -65,6 +67,7 @@ elegant thanks to channels and select.

             
           		
           
+	        
             
func main() {
 

 
@@ -79,6 +82,7 @@ after 2s.

 
           		
           
+	        
             
    c1 := make(chan string, 1)
     go func() {
         time.Sleep(time.Second * 2)
@@ -100,6 +104,7 @@ if the operation takes more than the allowed 1s.

 
           

           
+	        
             
    select {
     case res := <-c1:
         fmt.Println(res)
@@ -118,6 +123,7 @@ from c2 will succeed and we’ll print the result.

 
           

           
+	        
             
    c2 := make(chan string, 1)
     go func() {
         time.Sleep(time.Second * 2)
@@ -146,6 +152,7 @@ out and the second succeeding.

 
           

           
+	        
             
$ go run timeouts.go 
 timeout 1
 result 2
@@ -164,6 +171,7 @@ examples of this next: timers and tickers.

 
           

           
+	        
             
           
         

     

         
@@ -34,6 +33,7 @@ at tickers.

@@ -43,6 +43,7 @@ at tickers.

 
           
           

+	        
             
           
         

             
           
           

+	        
             
package main
 

 
@@ -54,6 +55,7 @@ at tickers.

             
           		
           
+	        
             
import "time"
 import "fmt"
 

@@ -66,6 +68,7 @@ at tickers.

             
           		
           
+	        
             
func main() {
 

 
@@ -81,6 +84,7 @@ time. This timer will wait 2 seconds.

 
           		
           
+	        
             
    timer1 := time.NewTimer(time.Second * 2)
 

 
@@ -95,6 +99,7 @@ expired.

 
           		
           
+	        
             
    <-timer1.C
     fmt.Println("Timer 1 expired")
 

@@ -111,6 +116,7 @@ Here’s an example of that.

 
           		
           
+	        
             
    timer2 := time.NewTimer(time.Second)
     go func() {
         <-timer2.C
@@ -138,6 +144,7 @@ a chance to expire.

 
           

           
+	        
             
$ go run timers.go
 Timer 1 expired
 Timer 2 stopped
diff --git a/public/url-parsing b/public/url-parsing
index aeeb426..b514a5e 100644
--- a/public/url-parsing
+++ b/public/url-parsing
@@ -20,7 +20,6 @@
   
     

       
Go by Example: URL Parsing

-      
       
       
         
@@ -31,6 +30,7 @@ Here’s how to parse URLs in Go.

@@ -40,6 +40,7 @@ Here’s how to parse URLs in Go.

 
           
           

+	        
             
           
         

             
           
           

+	        
             
package main
 

 
@@ -51,6 +52,7 @@ Here’s how to parse URLs in Go.

             
           		
           
+	        
             
import "fmt"
 import "net/url"
 import "strings"
@@ -64,6 +66,7 @@ Here’s how to parse URLs in Go.

             
           

           
+	        
             
func main() {
 

 
@@ -78,6 +81,7 @@ query params, and query fragment.

 
           		
           
+	        
             
    s := "postgres://user:pass@host.com:5432/path?k=v#f"
 

 
@@ -90,6 +94,7 @@ query params, and query fragment.

 
           		
           
+	        
             
    u, err := url.Parse(s)
     if err != nil {
         panic(err)
@@ -105,6 +110,7 @@ query params, and query fragment.

 
           

           
+	        
             
    fmt.Println(u.Scheme)
 

 
@@ -119,6 +125,7 @@ values.

 
           		
           
+	        
             
    fmt.Println(u.User)
     fmt.Println(u.User.Username())
     p, _ := u.User.Password()
@@ -136,6 +143,7 @@ the port.

 
           

           
+	        
             
    fmt.Println(u.Host)
     h := strings.Split(u.Host, ":")
     fmt.Println(h[0])
@@ -152,6 +160,7 @@ the #.

 
           

           
+	        
             
    fmt.Println(u.Path)
     fmt.Println(u.Fragment)
 

@@ -169,6 +178,7 @@ if you only want the first value.

 
           		
           
+	        
             
    fmt.Println(u.RawQuery)
     m, _ := url.ParseQuery(u.RawQuery)
     fmt.Println(m)
@@ -190,6 +200,7 @@ pieces that we extracted.

 
           

           
+	        
             
$ go run url-parsing.go 
 postgres
 user:pass
diff --git a/public/values b/public/values
index d332548..aeeee0f 100644
--- a/public/values
+++ b/public/values
@@ -20,7 +20,6 @@
   
     

       
Go by Example: Values

-      
       
       
         
@@ -32,6 +31,7 @@ basic examples.

@@ -41,6 +41,7 @@ basic examples.

 
           
           

+	        
             
           
         

             
           
           

+	        
             
package main
 

 
@@ -52,6 +53,7 @@ basic examples.

             
           		
           
+	        
             
import "fmt"
 

 
@@ -63,6 +65,7 @@ basic examples.

             
           		
           
+	        
             
func main() {
 

 
@@ -75,6 +78,7 @@ basic examples.

 
           		
           
+	        
             
    fmt.Println("go" + "lang")
 

 
@@ -87,6 +91,7 @@ basic examples.

 
           		
           
+	        
             
    fmt.Println("1+1 =", 1+1)
     fmt.Println("7.0/3.0 =", 7.0/3.0)
 

@@ -100,6 +105,7 @@ basic examples.

 
           		
           
+	        
             
    fmt.Println(true && false)
     fmt.Println(true || false)
     fmt.Println(!true)
@@ -118,6 +124,7 @@ basic examples.

             
           

           
+	        
             
$ go run values.go
 golang
 1+1 = 2
diff --git a/public/variables b/public/variables
index abd7a7f..7422d14 100644
--- a/public/variables
+++ b/public/variables
@@ -20,7 +20,6 @@
   
     

       
Go by Example: Variables

-      
       
       
         
@@ -32,6 +31,7 @@ calls.

@@ -41,6 +41,7 @@ calls.

 
           
           

+	        
             
           
         

             
           
           

+	        
             
package main
 

 
@@ -52,6 +53,7 @@ calls.

             
           		
           
+	        
             
import "fmt"
 

 
@@ -63,6 +65,7 @@ calls.

             
           		
           
+	        
             
func main() {
 

 
@@ -75,6 +78,7 @@ calls.

 
           		
           
+	        
             
    var a string = "initial"
     fmt.Println(a)
 

@@ -88,6 +92,7 @@ calls.

 
           		
           
+	        
             
    var b, c int = 1, 2
     fmt.Println(b, c)
 

@@ -101,6 +106,7 @@ calls.

 
           		
           
+	        
             
    var d = true
     fmt.Println(d)
 

@@ -116,6 +122,7 @@ zero value for an int is 0.

 
           		
           
+	        
             
    var e int
     fmt.Println(e)
 

@@ -131,6 +138,7 @@ initializing a variable, e.g. for
 
           		
           
+	        
             
    f := "short"
     fmt.Println(f)
 }
@@ -148,6 +156,7 @@ initializing a variable, e.g. for
             
           

           
+	        
             
$ go run variables.go
 initial
 1 2
diff --git a/public/variadic-functions b/public/variadic-functions
index 738256c..653c773 100644
--- a/public/variadic-functions
+++ b/public/variadic-functions
@@ -20,7 +20,6 @@
   
     

       
Go by Example: Variadic Functions

-      
       
       
         
@@ -33,6 +32,7 @@ function.

@@ -42,6 +42,7 @@ function.

diff --git a/public/worker-pools b/public/worker-pools
index 5a9fe7e..1471e84 100644
--- a/public/worker-pools
+++ b/public/worker-pools
@@ -20,7 +20,6 @@
   

       
Go by Example: Worker Pools

-      
       
       

 
           
           

+	        
             
           
         

             
           
           

+	        
             
package main
 

 
@@ -53,6 +54,7 @@ function.

             
           		
           
+	        
             
import "fmt"
 

 
@@ -66,6 +68,7 @@ of ints as arguments.

 
           		
           
+	        
             
func sum(nums ...int) {
     fmt.Print(nums, " ")
     total := 0
@@ -84,6 +87,7 @@ of ints as arguments.

             
           

           
+	        
             
func main() {
 

 
@@ -97,6 +101,7 @@ with individual arguments.

 
           		
           
+	        
             
    sum(1, 2)
     sum(1, 2, 3)
 

@@ -112,6 +117,7 @@ apply them to a variadic function using
 
           		
           
+	        
             
    nums := []int{1, 2, 3, 4}
     sum(nums...)
 }
@@ -129,6 +135,7 @@ apply them to a variadic function using
             
           

           
+	        
             
$ go run variadic-functions.go 
 [1 2] 3
 [1 2 3] 6
@@ -145,6 +152,7 @@ to form closures, which we’ll look at next.

 
           

           
+	        
             
           
         

     

         
@@ -31,6 +30,7 @@ a worker pool using goroutines and channels.

@@ -40,6 +40,7 @@ a worker pool using goroutines and channels.

 
           
           

+	        
             
           
         

             
           
           

+	        
             
package main
 

 
@@ -51,6 +52,7 @@ a worker pool using goroutines and channels.

             
           		
           
+	        
             
import "fmt"
 import "time"
 

@@ -68,6 +70,7 @@ simulate an expensive task.

 
           		
           
+	        
             
func worker(id int, jobs <-chan int, results chan<- int) {
     for j := range jobs {
         fmt.Println("worker", id, "processing job", j)
@@ -85,6 +88,7 @@ simulate an expensive task.

             
           

           
+	        
             
func main() {
 

 
@@ -99,6 +103,7 @@ channels for this.

 
           		
           
+	        
             
    jobs := make(chan int, 100)
     results := make(chan int, 100)
 

@@ -113,6 +118,7 @@ because there are no jobs yet.

 
           		
           
+	        
             
    for w := 1; w <= 3; w++ {
         go worker(w, jobs, results)
     }
@@ -128,6 +134,7 @@ channel to indicate that’s all the work we have.

 
           

           
+	        
             
    for j := 1; j <= 9; j++ {
         jobs <- j
     }
@@ -143,6 +150,7 @@ channel to indicate that’s all the work we have.

 
           

           
+	        
             
    for a := 1; a <= 9; a++ {
         <-results
     }
@@ -165,6 +173,7 @@ there are 3 workers operating concurrently.

 
           

           
+	        
             
$ time go run worker-pools.go 
 worker 1 processing job 1
 worker 2 processing job 2
@@ -185,6 +194,7 @@ there are 3 workers operating concurrently.

             
           

           
+	        
             
real	0m3.149s
 

 
diff --git a/public/writing-files b/public/writing-files
index 7d4f2c1..dc9f576 100644
--- a/public/writing-files
+++ b/public/writing-files
@@ -20,7 +20,6 @@
   
     

       
Go by Example: Writing Files

-      
       
       
         
@@ -31,6 +30,7 @@ ones we saw earlier for reading.

@@ -40,6 +40,7 @@ ones we saw earlier for reading.

diff --git a/templates/example.tmpl b/templates/example.tmpl
index bf048eb..db3dc96 100644
--- a/templates/example.tmpl
+++ b/templates/example.tmpl
@@ -20,7 +20,6 @@
   

       
Go by Example: {{.Name}}

-      
       {{range .Segs}}
       

 
           
           

+	        
             
           
         

             
           
           

+	        
             
package main
 

 
@@ -51,6 +52,7 @@ ones we saw earlier for reading.

             
           		
           
+	        
             
import (
     "bufio"
     "fmt"
@@ -67,6 +69,7 @@ ones we saw earlier for reading.

             
           

           
+	        
             
func check(e error) {
     if e != nil {
         panic(e)
@@ -82,6 +85,7 @@ ones we saw earlier for reading.

             
           

           
+	        
             
func main() {
 

 
@@ -95,6 +99,7 @@ bytes) into a file.

 
           		
           
+	        
             
    d1 := []byte("hello\ngo\n")
     err := ioutil.WriteFile("/tmp/dat1", d1, 0644)
     check(err)
@@ -109,6 +114,7 @@ bytes) into a file.

 
           

           
+	        
             
    f, err := os.Create("/tmp/dat2")
     check(err)
 

@@ -123,6 +129,7 @@ after opening a file.

 
           		
           
+	        
             
    defer f.Close()
 

 
@@ -135,6 +142,7 @@ after opening a file.

 
           		
           
+	        
             
    d2 := []byte{115, 111, 109, 101, 10}
     n2, err := f.Write(d2)
     check(err)
@@ -150,6 +158,7 @@ after opening a file.

 
           

           
+	        
             
    n3, err := f.WriteString("writes\n")
     fmt.Printf("wrote %d bytes\n", n3)
 

@@ -163,6 +172,7 @@ after opening a file.

 
           		
           
+	        
             
    f.Sync()
 

 
@@ -176,6 +186,7 @@ to the buffered readers we saw earlier.

 
           		
           
+	        
             
    w := bufio.NewWriter(f)
     n4, err := w.WriteString("buffered\n")
     fmt.Printf("wrote %d bytes\n", n4)
@@ -191,6 +202,7 @@ been applied to the underlying writer.

 
           

           
+	        
             
    w.Flush()
 

 
@@ -202,6 +214,7 @@ been applied to the underlying writer.

             
           		
           
+	        
             
}
 

 
@@ -218,6 +231,7 @@ been applied to the underlying writer.

 
           		
           
+	        
             
$ go run writing-files.go 
 wrote 5 bytes
 wrote 7 bytes
@@ -233,6 +247,7 @@ been applied to the underlying writer.

 
           

           
+	        
             
$ cat /tmp/dat1
 hello
 go
@@ -252,6 +267,7 @@ we’ve just seen to the stdin and stdout streams.
 
           

           
+	        
             
           
         

     

         {{range .}}
@@ -29,6 +28,7 @@
             {{.DocsRendered}}
           
diff --git a/tools/generate.go b/tools/generate.go
index 4f1cc13..30d7291 100644
--- a/tools/generate.go
+++ b/tools/generate.go
@@ -118,9 +118,9 @@ var todoPat = regexp.MustCompile("\\/\\/ todo: ")
 var dashPat = regexp.MustCompile("\\-+")
 
 type Seg struct {
-    Docs, DocsRendered     string
-    Code, CodeRendered     string
-    CodeEmpty, CodeLeading bool
+    Docs, DocsRendered              string
+    Code, CodeRendered              string
+    CodeEmpty, CodeLeading, CodeRun bool
 }
 
 type Example struct {
@@ -193,6 +193,7 @@ func parseSegs(sourcePath string) ([]*Seg, string) {
     for i, seg := range segs {
         seg.CodeEmpty = (seg.Code == "")
         seg.CodeLeading = (i < (len(segs) - 1))
+        seg.CodeRun = strings.Contains(seg.Code, "package main")
     }
     return segs, filecontent
 }


           

+	        {{if .CodeRun}}{{end}}
             {{.CodeRendered}}