doc update

README.md

@@ -3,7 +3,7 @@
 [![Build Status](https://travis-ci.org/emicklei/proto.png)](https://travis-ci.org/emicklei/proto)
 [![GoDoc](https://godoc.org/github.com/emicklei/proto?status.svg)](https://godoc.org/github.com/emicklei/proto)
 
-Package in Go for parsing Google Protocol Buffers [.proto files version 2 + 3] (https://developers.google.com/protocol-buffers/docs/reference/proto-spec)
+Package in Go for parsing and formatting Google Protocol Buffers [.proto files version 2 + 3] (https://developers.google.com/protocol-buffers/docs/reference/proto-spec)
 
 ### usage
 

visitor.go

@@ -24,10 +24,14 @@ type Visitee interface {
 	Accept(v Visitor)
 }
 
+// reflector is a Visitor that can tell the short type name of a Visitee.
 type reflector struct {
 	name string
 }
 
+// sole instance of reflector
+var namer = new(reflector)
+
 func (r *reflector) VisitMessage(m *Message)         { r.name = "Message" }
 func (r *reflector) VisitService(v *Service)         { r.name = "Service" }
 func (r *reflector) VisitSyntax(s *Syntax)           { r.name = "Syntax" }
@@ -44,8 +48,8 @@ func (r *reflector) VisitReserved(rs *Reserved)      { r.name = "Reserved" }
 func (r *reflector) VisitRPC(rpc *RPC)               { r.name = "RPC" }
 func (r *reflector) VisitMapField(f *MapField)       { r.name = "MapField" }
 
+// nameOfVisitee returns the short type name of a Visitee.
 func nameOfVisitee(e Visitee) string {
-	r := new(reflector)
-	e.Accept(r)
-	return r.name
+	e.Accept(namer)
+	return namer.name
 }