effective_go: convert to use tmpltohtml.

Also update the big example to the new template system.
There are a number of other examples that should be
extracted; this CL serves as an introduction to the
approach.

R=golang-dev, adg
CC=golang-dev
https://golang.org/cl/4923043

doc/Makefile

@@ -8,4 +8,11 @@ TARG=tmpltohtml
 GOFILES=\
 	tmpltohtml.go\
 
+go_tutorial.html: go_tutorial.tmpl tmpltohtml
+	makehtml go_tutorial.tmpl
+
+effective_go.html: effective_go.tmpl tmpltohtml
+	makehtml effective_go.tmpl
+
+
 include ../src/Make.cmd

doc/effective_go.html

@@ -793,7 +793,7 @@ func ReadFull(r Reader, buf []byte) (n int, err os.Error) {
         var nr int
         nr, err = r.Read(buf)
         n += nr
-        buf = buf[nr:len(buf)]
+        buf = buf[nr:]
     }
     return
 }
@@ -954,8 +954,9 @@ In Go terminology, it returns a pointer to a newly allocated zero value of type
 </p>
 
 <p>
-Since the memory returned by <code>new</code> is zeroed, it's helpful to arrange that the
+Since the memory returned by <code>new</code> is zeroed, it's helpful to arrange
-zeroed object can be used without further initialization.  This means a user of
+when designing your data structures that the
+zero value of each type can be used without further initialization.  This means a user of
 the data structure can create one with <code>new</code> and get right to
 work.
 For example, the documentation for <code>bytes.Buffer</code> states that
@@ -1075,8 +1076,9 @@ m := map[int]string{Enone: "no error", Eio: "Eio", Einval: "invalid argument"}
 Back to allocation.
 The built-in function <code>make(T, </code><i>args</i><code>)</code> serves
 a purpose different from <code>new(T)</code>.
-It creates slices, maps, and channels only, and it returns an initialized (not zero)
+It creates slices, maps, and channels only, and it returns an <em>initialized</em>
-value of type <code>T</code>, not <code>*T</code>.
+(not <em>zeroed</em>)
+value of type <code>T</code> (not <code>*T</code>).
 The reason for the distinction
 is that these three types are, under the covers, references to data structures that
 must be initialized before use.
@@ -2917,66 +2919,55 @@ for instance, a URL, saving you typing the URL into the phone's tiny keyboard.
 Here's the complete program.
 An explanation follows.
 </p>
-
+<pre><!--{{code "progs/eff_qr.go"}}
-<pre>
+-->package main
-package main
 
 import (
-    "flag"
+    &#34;flag&#34;
-    "http"
+    &#34;http&#34;
-    "io"
+    &#34;log&#34;
-    "log"
+    &#34;template&#34;
-    "old/template" // New template package coming soon...
 )
 
-var addr = flag.String("addr", ":1718", "http service address") // Q=17, R=18
+var addr = flag.String(&#34;addr&#34;, &#34;:1718&#34;, &#34;http service address&#34;) // Q=17, R=18
-var fmap = template.FormatterMap{
+
-    "html": template.HTMLFormatter,
+var templ = template.Must(template.New(&#34;qr&#34;).Parse(templateStr))
-    "url+html": UrlHtmlFormatter,
-}
-var templ = template.MustParse(templateStr, fmap)
 
 func main() {
     flag.Parse()
-    http.Handle("/", http.HandlerFunc(QR))
+    http.Handle(&#34;/&#34;, http.HandlerFunc(QR))
     err := http.ListenAndServe(*addr, nil)
     if err != nil {
-        log.Fatal("ListenAndServe:", err)
+        log.Fatal(&#34;ListenAndServe:&#34;, err)
     }
 }
 
 func QR(w http.ResponseWriter, req *http.Request) {
-    templ.Execute(w, req.FormValue("s"))
+    templ.Execute(w, req.FormValue(&#34;s&#34;))
 }
 
-func UrlHtmlFormatter(w io.Writer, fmt string, v ...interface{}) {
-    template.HTMLEscape(w, []byte(http.URLEscape(v[0].(string))))
-}
-
-
 const templateStr = `
 &lt;html&gt;
 &lt;head&gt;
 &lt;title&gt;QR Link Generator&lt;/title&gt;
 &lt;/head&gt;
 &lt;body&gt;
-{.section @}
+{{if .}}
-&lt;img src="http://chart.apis.google.com/chart?chs=300x300&amp;cht=qr&amp;choe=UTF-8&amp;chl={@|url+html}"
+&lt;img src=&#34;http://chart.apis.google.com/chart?chs=300x300&amp;amp;cht=qr&amp;amp;choe=UTF-8&amp;amp;chl={{urlquery .}}&#34;
 /&gt;
 &lt;br&gt;
-{@|html}
+{{html .}}
 &lt;br&gt;
 &lt;br&gt;
-{.end}
+{{end}}
-&lt;form action="/" name=f method="GET"&gt;&lt;input maxLength=1024 size=70
+&lt;form action=&#34;/&#34; name=f method=&#34;GET&#34;&gt;&lt;input maxLength=1024 size=70
-name=s value="" title="Text to QR Encode"&gt;&lt;input type=submit
+name=s value=&#34;&#34; title=&#34;Text to QR Encode&#34;&gt;&lt;input type=submit
-value="Show QR" name=qr&gt;
+value=&#34;Show QR&#34; name=qr&gt;
 &lt;/form&gt;
 &lt;/body&gt;
 &lt;/html&gt;
 `
 </pre>
-
 <p>
 The pieces up to <code>main</code> should be easy to follow.
 The one flag sets a default HTTP port for our server.  The template
@@ -2995,25 +2986,20 @@ server; it blocks while the server runs.
 executes the template on the data in the form value named <code>s</code>.
 </p>
 <p>
-The template package, inspired by <a
+The template package is powerful;
-href="http://code.google.com/p/json-template">json-template</a>, is
-powerful;
 this program just touches on its capabilities.
 In essence, it rewrites a piece of text on the fly by substituting elements derived
 from data items passed to <code>templ.Execute</code>, in this case the
 form value.  
 Within the template text (<code>templateStr</code>),
-brace-delimited pieces denote template actions.
+double-brace-delimited pieces denote template actions.
-The piece from the <code>{.section @}</code>
+The piece from the <code></code> executes only if the value of the current data item, called <code>.</code>,
-to <code>{.end}</code> executes with the value of the data item <code>@</code>,
+is non-empty.
-which is a shorthand for &ldquo;the current item&rdquo;, which is the form value.
+That is, when the string is empty, this piece of the template is suppressed.
-(When the string is empty, this piece of the template is suppressed.)
 </p>
 <p>
-The snippet <code>{@|url+html}</code> says to run the data through the formatter
+The snippet <code>0</code> says to process the data with the function
-installed in the formatter map (<code>fmap</code>)
+<code>urlquery</code>, which sanitizes the query string
-under the name <code>"url+html"</code>.
-That is the function <code>UrlHtmlFormatter</code>, which sanitizes the string
 for safe display on the web page.
 </p>
 <p>

doc/makehtml

@@ -14,4 +14,4 @@ then
 	exit 1
 fi
 
-make && ./tmpltohtml $TMPL > $HTML
+make tmpltohtml && ./tmpltohtml $TMPL > $HTML

doc/progs/eff_qr.go

@@ -0,0 +1,47 @@
+package main
+
+import (
+	"flag"
+	"http"
+	"log"
+	"template"
+)
+
+var addr = flag.String("addr", ":1718", "http service address") // Q=17, R=18
+
+var templ = template.Must(template.New("qr").Parse(templateStr))
+
+func main() {
+	flag.Parse()
+	http.Handle("/", http.HandlerFunc(QR))
+	err := http.ListenAndServe(*addr, nil)
+	if err != nil {
+		log.Fatal("ListenAndServe:", err)
+	}
+}
+
+func QR(w http.ResponseWriter, req *http.Request) {
+	templ.Execute(w, req.FormValue("s"))
+}
+
+const templateStr = `
+<html>
+<head>
+<title>QR Link Generator</title>
+</head>
+<body>
+{{if .}}
+<img src="http://chart.apis.google.com/chart?chs=300x300&amp;cht=qr&amp;choe=UTF-8&amp;chl={{urlquery .}}"
+/>
+<br>
+{{html .}}
+<br>
+<br>
+{{end}}
+<form action="/" name=f method="GET"><input maxLength=1024 size=70
+name=s value="" title="Text to QR Encode"><input type=submit
+value="Show QR" name=qr>
+</form>
+</body>
+</html>
+`

doc/progs/run

@@ -35,6 +35,7 @@ for i in \
 	sieve1.go \
 	server1.go \
 	strings.go \
+	eff_qr.go \
 ; do
 	$GC $i
 done