diff --git a/comment/comment.go b/comment/comment.go
index f9d7de1..f65f067 100644
--- a/comment/comment.go
+++ b/comment/comment.go
@@ -2,12 +2,15 @@ package comment
 
 import "github.com/z7zmey/php-parser/node"
 
+// Comment represents comment lines in the code
 type Comment interface {
 	String() string
 }
 
+// Comments a collection of comment groups assigned to nodes
 type Comments map[node.Node][]Comment
 
+// AddComments add comment group to the collection
 func (c Comments) AddComments(node node.Node, comments []Comment) {
 	c[node] = append(c[node], comments...)
 }
diff --git a/comment/doc_comment.go b/comment/doc_comment.go
index 8988e64..c0b9a93 100644
--- a/comment/doc_comment.go
+++ b/comment/doc_comment.go
@@ -1,9 +1,11 @@
 package comment
 
+// DocComment represents comments that start /**
 type DocComment struct {
 	value string
 }
 
+// NewDocComment - DocComment constructor
 func NewDocComment(value string) *DocComment {
 	return &DocComment{
 		value,
diff --git a/comment/plain_comment.go b/comment/plain_comment.go
index ea8a0c5..89371a8 100644
--- a/comment/plain_comment.go
+++ b/comment/plain_comment.go
@@ -1,9 +1,11 @@
 package comment
 
+// PlainComment represents comments that dont start /**
 type PlainComment struct {
 	value string
 }
 
+// NewPlainComment - PlainComment constructor
 func NewPlainComment(value string) *PlainComment {
 	return &PlainComment{
 		value,
diff --git a/position/position.go b/position/position.go
index 7448cfa..f619e7b 100644
--- a/position/position.go
+++ b/position/position.go
@@ -6,6 +6,7 @@ import (
 	"github.com/z7zmey/php-parser/node"
 )
 
+// Position represents node position
 type Position struct {
 	StartLine int
 	EndLine   int
@@ -17,8 +18,10 @@ func (p Position) String() string {
 	return fmt.Sprintf("Pos{Line: %d-%d Pos: %d-%d}", p.StartLine, p.EndLine, p.StartPos, p.EndPos)
 }
 
+// Positions a collection of positions attached to nodes
 type Positions map[node.Node]*Position
 
+// AddPosition attaches a position to a node
 func (p Positions) AddPosition(node node.Node, position *Position) {
 	p[node] = position
 }