Merging issue 280 with master changes (#296)

mapper.go

@@ -274,7 +274,8 @@ func (r *Registry) RegisterDefaults() *Registry {
 		RegisterName("path", pathMapper(r)).
 		RegisterName("existingfile", existingFileMapper(r)).
 		RegisterName("existingdir", existingDirMapper(r)).
-		RegisterName("counter", counterMapper())
+		RegisterName("counter", counterMapper()).
+		RegisterKind(reflect.Ptr, ptrMapper(r))
 }
 
 type boolMapper struct{}
@@ -669,6 +670,22 @@ func existingDirMapper(r *Registry) MapperFunc {
 	}
 }
 
+func ptrMapper(r *Registry) MapperFunc {
+	return func(ctx *DecodeContext, target reflect.Value) error {
+		elem := reflect.New(target.Type().Elem()).Elem()
+		nestedMapper := r.ForValue(elem)
+		if nestedMapper == nil {
+			return fmt.Errorf("cannot find mapper for %v", target.Type().Elem().String())
+		}
+		err := nestedMapper.Decode(ctx, elem)
+		if err != nil {
+			return err
+		}
+		target.Set(elem.Addr())
+		return nil
+	}
+}
+
 func counterMapper() MapperFunc {
 	return func(ctx *DecodeContext, target reflect.Value) error {
 		if ctx.Scan.Peek().Type == FlagValueToken {