diff --git a/ast/base.go b/ast/base.go
new file mode 100644
index 0000000..f129bed
--- /dev/null
+++ b/ast/base.go
@@ -0,0 +1,13 @@
+package ast
+
+type BaseNode struct {
+	ID NodeID
+}
+
+func (node *BaseNode) initBaseNode(id NodeID) {
+	node.ID = id
+}
+
+func (node *BaseNode) Name() string {
+	return NodeNames[node.ID]
+}
diff --git a/ast/compoundstatement.go b/ast/compoundstatement.go
new file mode 100644
index 0000000..ea3cc46
--- /dev/null
+++ b/ast/compoundstatement.go
@@ -0,0 +1,13 @@
+package ast
+
+type CompoundStatement struct {
+	Statement
+}
+
+func NewCompoundStatement() *CompoundStatement {
+	node := &CompoundStatement{}
+	node.initBaseNode(SIMPLE_STMT)
+	return node
+}
+
+func (node *CompoundStatement) StatementNode() {}
diff --git a/ast/expressionstatement.go b/ast/expressionstatement.go
new file mode 100644
index 0000000..b7b6ddf
--- /dev/null
+++ b/ast/expressionstatement.go
@@ -0,0 +1,13 @@
+package ast
+
+type ExpressionStatement struct {
+	BaseNode
+}
+
+func NewExpressionStatement() *ExpressionStatement {
+	node := &ExpressionStatement{}
+	node.initBaseNode(EXPR_STMT)
+	return node
+}
+
+func (node *ExpressionStatement) SmallStatementNode() {}
diff --git a/ast/node.go b/ast/node.go
index 3d50198..bbc0d0a 100644
--- a/ast/node.go
+++ b/ast/node.go
@@ -1,6 +1,5 @@
 package ast
 
 type Node interface {
-	ID() NodeID
 	Name() string
 }
diff --git a/ast/simplestatement.go b/ast/simplestatement.go
new file mode 100644
index 0000000..517d5d7
--- /dev/null
+++ b/ast/simplestatement.go
@@ -0,0 +1,18 @@
+package ast
+
+type SimpleStatement struct {
+	BaseNode
+	Statements []*SmallStatement
+}
+
+func NewSimpleStatement() *SimpleStatement {
+	node := &SimpleStatement{}
+	node.initBaseNode(SIMPLE_STMT)
+	return node
+}
+
+func (node *SimpleStatement) StatementNode() {}
+
+func (node *SimpleStatement) AppendSmallStatement(n *SmallStatement) {
+	node.Statements = append(node.Statements, n)
+}
diff --git a/ast/smallstatement.go b/ast/smallstatement.go
new file mode 100644
index 0000000..afaf76a
--- /dev/null
+++ b/ast/smallstatement.go
@@ -0,0 +1,16 @@
+package ast
+
+type SmallStatementNode interface {
+	SmallStatementNode()
+}
+
+type SmallStatement struct {
+	BaseNode
+	Statement SmallStatementNode
+}
+
+func NewSmallStatement() *SmallStatement {
+	node := &SmallStatement{}
+	node.initBaseNode(SMALL_STMT)
+	return node
+}
diff --git a/ast/statement.go b/ast/statement.go
new file mode 100644
index 0000000..ace66b3
--- /dev/null
+++ b/ast/statement.go
@@ -0,0 +1,18 @@
+package ast
+
+type StatementNode interface {
+	StatementNode()
+}
+
+type Statement struct {
+	BaseNode
+	Statement StatementNode
+}
+
+func NewStatement() *Statement {
+	node := &Statement{}
+	node.initBaseNode(STMT)
+	return node
+}
+
+func (node *Statement) StatementNode() {}