Add flag -u to make examples unique

cmd/zek/main.go

@@ -27,6 +27,7 @@ var (
 	version              = flag.Bool("version", false, "show version")
 	structName           = flag.String("n", "", "use a different name for the top-level struct")
 	compact              = flag.Bool("c", false, "emit more compact struct")
+	uniqueExamples       = flag.Bool("u", false, "filter out duplicated examples")
 )
 
 func main() {
@@ -80,6 +81,7 @@ func main() {
 		sw.Strict = *strict
 		sw.ExampleMaxChars = *exampleMaxChars
 		sw.Compact = *compact
+		sw.UniqueExamples = *uniqueExamples
 
 		if err := sw.WriteNode(root); err != nil {
 			log.Fatal(err)

structwriter.go

@@ -90,6 +90,7 @@ type StructWriter struct {
 	Strict            bool                // Whether to ignore implementation holes.
 	WithJSONTags      bool                // Include JSON struct tags.
 	Compact           bool                // Emit more compact struct.
+	UniqueExamples    bool                // Filter out duplicated examples
 }
 
 // NewStructWriter can write a node to a given writer. Default list of
@@ -176,6 +177,11 @@ func (sw *StructWriter) writeChardataField(w io.Writer, node *Node) (int, error)
 	} else {
 		s = fmt.Sprintf("%s string `xml:\",chardata\"`", textFieldName)
 	}
+
+	if sw.UniqueExamples {
+		node.Examples = uniqueStrings(node.Examples)
+	}
+
 	if sw.WithComments && len(node.Examples) > 0 {
 		examples := strings.Replace(strings.Join(node.Examples, ", "), "\n", " ", -1)
 		s = fmt.Sprintf("%s // %s", s, truncateString(examples, sw.ExampleMaxChars, "..."))
@@ -215,6 +221,10 @@ func (sw *StructWriter) writeNode(node *Node, top bool) (err error) {
 		io.WriteString(sew, "[]")
 	}
 
+	if sw.UniqueExamples {
+		node.Examples = uniqueStrings(node.Examples)
+	}
+
 	if sw.Compact && len(node.Children) == 0 && len(node.Attr) == 0 {
 		s := fmt.Sprintf("string `xml:\"%s\"`", node.Name.Local)
 		if sw.WithComments && len(node.Examples) > 0 {
@@ -282,3 +292,15 @@ func (sw *StructWriter) writeNode(node *Node, top bool) (err error) {
 	io.WriteString(sew, "\n")
 	return err
 }
+
+func uniqueStrings(ss []string) []string {
+	uniq := make([]string, 0, len(ss))
+	m := map[string]struct{}{}
+	for _, s := range ss {
+		if _, ok := m[s]; !ok {
+			uniq = append(uniq, s)
+			m[s] = struct{}{}
+		}
+	}
+	return uniq
+}