5 files changed, 19 insertions, 33 deletions
diff --git a/doc/codewalk/functions.xml b/doc/codewalk/functions.xml
index 986a017e1..db518dcc0 100644
--- a/doc/codewalk/functions.xml
+++ b/doc/codewalk/functions.xml
@@ -45,7 +45,7 @@
   turn.
 </step>
 
-<step title="Multiple return values" src="doc/codewalk/pig.go:/\/\/ roll returns/,/stay.*true\n}/">
+<step title="Multiple return values" src="doc/codewalk/pig.go:/\/\/ roll returns/,/true\n}/">
 	Go functions can return multiple values.  
 	<br/><br/>
 
@@ -82,16 +82,6 @@
   associated with the current player.
 </step>
 
-<step title="Comparing functions" src="doc/codewalk/pig.go:/if action/,/currentPlayer\)\)\n\t\t}/">
-	Functions can be compared for equality in Go.  From the 
-	<a href="http://golang.org/doc/go_spec.html#Comparison_operators">language specification</a>:
-  Function values are equal if they refer to the same function or if both are <code>nil</code>.
-	<br/><br/>
-
-  We enforce that a <code>strategy</code> function can only return a legal
-  <code>action</code>: either <code>roll</code> or <code>stay</code>.
-</step>
-
 <step title="Simulating a tournament" src="doc/codewalk/pig.go:/\/\/ roundRobin/,/gamesPerStrategy\n}/">
 	The <code>roundRobin</code> function simulates a tournament and tallies wins.
 	Each strategy plays each other strategy <code>gamesPerSeries</code> times.
diff --git a/doc/codewalk/markov.go b/doc/codewalk/markov.go
index 959c2b158..cb28eb0bc 100644
--- a/doc/codewalk/markov.go
+++ b/doc/codewalk/markov.go
@@ -50,8 +50,8 @@ import (
 	"flag"
 	"fmt"
 	"io"
+	"math/rand"
 	"os"
-	"rand"
 	"strings"
 	"time"
 )
diff --git a/doc/codewalk/markov.xml b/doc/codewalk/markov.xml
index a89b4d0ce..81df1289c 100644
--- a/doc/codewalk/markov.xml
+++ b/doc/codewalk/markov.xml
@@ -105,7 +105,7 @@ Prefix               Map key
 	reads space-separated values from an <code>io.Reader</code>.
 	<br/><br/>
 	The <code>Build</code> method returns once the <code>Reader</code>'s
-	<code>Read</code> method returns <code>os.EOF</code> (end of file)
+	<code>Read</code> method returns <code>io.EOF</code> (end of file)
 	or some other read error occurs.
 </step>
 
@@ -133,7 +133,7 @@ Prefix               Map key
 	(including punctuation), which is exactly what we need.
 	<br/><br/>
 	<code>Fscan</code> returns an error if it encounters a read error
-	(<code>os.EOF</code>, for example) or if it can't scan the requested
+	(<code>io.EOF</code>, for example) or if it can't scan the requested
 	value (in our case, a single string). In either case we just want to
 	stop scanning, so we <code>break</code> out of the loop.
 </step>
diff --git a/doc/codewalk/pig.go b/doc/codewalk/pig.go
index 9e415f589..10963b4e4 100644
--- a/doc/codewalk/pig.go
+++ b/doc/codewalk/pig.go
@@ -6,7 +6,7 @@ package main
 
 import (
 	"fmt"
-	"rand"
+	"math/rand"
 )
 
 const (
@@ -61,9 +61,6 @@ func play(strategy0, strategy1 strategy) int {
 	currentPlayer := rand.Intn(2) // Randomly decide who plays first
 	for s.player+s.thisTurn < win {
 		action := strategies[currentPlayer](s)
-		if action != roll && action != stay {
-			panic(fmt.Sprintf("Player %d is cheating", currentPlayer))
-		}
 		s, turnIsOver = action(s)
 		if turnIsOver {
 			currentPlayer = (currentPlayer + 1) % 2
diff --git a/doc/codewalk/urlpoll.go b/doc/codewalk/urlpoll.go
index b51be9502..e716c7e6c 100644
--- a/doc/codewalk/urlpoll.go
+++ b/doc/codewalk/urlpoll.go
@@ -5,17 +5,16 @@
 package main
 
 import (
-	"http"
 	"log"
+	"net/http"
 	"time"
 )
 
 const (
-	numPollers     = 2           // number of Poller goroutines to launch
-	second         = 1e9         // one second is 1e9 nanoseconds
-	pollInterval   = 60 * second // how often to poll each URL
-	statusInterval = 10 * second // how often to log status to stdout
-	errTimeout     = 10 * second // back-off timeout on error
+	numPollers     = 2                // number of Poller goroutines to launch
+	pollInterval   = 60 * time.Second // how often to poll each URL
+	statusInterval = 10 * time.Second // how often to log status to stdout
+	errTimeout     = 10 * time.Second // back-off timeout on error
 )
 
 var urls = []string{
@@ -33,7 +32,7 @@ type State struct {
 // StateMonitor maintains a map that stores the state of the URLs being
 // polled, and prints the current state every updateInterval nanoseconds.
 // It returns a chan State to which resource state should be sent.
-func StateMonitor(updateInterval int64) chan<- State {
+func StateMonitor(updateInterval time.Duration) chan<- State {
 	updates := make(chan State)
 	urlStatus := make(map[string]string)
 	ticker := time.NewTicker(updateInterval)
@@ -61,7 +60,7 @@ func logState(s map[string]string) {
 // Resource represents an HTTP URL to be polled by this program.
 type Resource struct {
 	url      string
-	errCount int64
+	errCount int
 }
 
 // Poll executes an HTTP HEAD request for url
@@ -71,7 +70,7 @@ func (r *Resource) Poll() string {
 	if err != nil {
 		log.Println("Error", r.url, err)
 		r.errCount++
-		return err.String()
+		return err.Error()
 	}
 	r.errCount = 0
 	return resp.Status
@@ -79,8 +78,8 @@ func (r *Resource) Poll() string {
 
 // Sleep sleeps for an appropriate interval (dependant on error state)
 // before sending the Resource to done.
-func (r *Resource) Sleep(done chan *Resource) {
-	time.Sleep(pollInterval + errTimeout*r.errCount)
+func (r *Resource) Sleep(done chan<- *Resource) {
+	time.Sleep(pollInterval + errTimeout*time.Duration(r.errCount))
 	done <- r
 }
 
@@ -93,18 +92,18 @@ func Poller(in <-chan *Resource, out chan<- *Resource, status chan<- State) {
 }
 
 func main() {
-	// create our input and output channels
+	// Create our input and output channels.
 	pending, complete := make(chan *Resource), make(chan *Resource)
 
-	// launch the StateMonitor
+	// Launch the StateMonitor.
 	status := StateMonitor(statusInterval)
 
-	// launch some Poller goroutines
+	// Launch some Poller goroutines.
 	for i := 0; i < numPollers; i++ {
 		go Poller(pending, complete, status)
 	}
 
-	// send some Resources to the pending queue
+	// Send some Resources to the pending queue.
 	go func() {
 		for _, url := range urls {
 			pending <- &Resource{url: url}