add chapter 15.7 (#683)

eBook/examples/chapter_15/template_field.go

@@ -0,0 +1,24 @@
+// template_field.go
+package main
+
+import (
+	"fmt"
+	"os"
+	"text/template"
+)
+
+type Person struct {
+	Name string
+	nonExportedAgeField string
+}
+
+func main() {
+	t := template.New("hello")
+	t, _ = t.Parse("hello {{.Name}}!")
+	p := Person{Name: "Mary", nonExportedAgeField: "31"}
+	if err := t.Execute(os.Stdout, p); err != nil {
+		fmt.Println("There was an error:", err.Error())
+	}
+}
+
+// Output:   hello Mary!