[refactoring] update ast structure of "Argument" and "ArgumentList" nodes

pkg/ast/node.go

@@ -90,7 +90,10 @@ func (n *Identifier) Accept(v NodeVisitor) {
 // ArgumentList node
 type ArgumentList struct {
 	Node
-	Arguments []Vertex
+	OpenParenthesisTkn  *token.Token
+	Arguments           []Vertex
+	SeparatorTkns       []*token.Token
+	CloseParenthesisTkn *token.Token
 }
 
 func (n *ArgumentList) Accept(v NodeVisitor) {
@@ -100,9 +103,9 @@ func (n *ArgumentList) Accept(v NodeVisitor) {
 // Argument node
 type Argument struct {
 	Node
-	Variadic    bool
-	IsReference bool
-	Expr        Vertex
+	VariadicTkn  *token.Token
+	AmpersandTkn *token.Token
+	Expr         Vertex
 }
 
 func (n *Argument) Accept(v NodeVisitor) {

pkg/ast/visitor/dump.go

@@ -240,16 +240,6 @@ func (v *Dump) Argument(n *ast.Argument) {
 	v.printIndentIfNotSingle(v.indent - 1)
 	v.print("&ast.Argument{\n")
 	v.printNode(n.GetNode())
-
-	if n.Variadic {
-		v.printIndent(v.indent)
-		v.print("Variadic: true,\n")
-	}
-
-	if n.IsReference {
-		v.printIndent(v.indent)
-		v.print("IsReference: true,\n")
-	}
 }
 
 func (v *Dump) StmtBreak(n *ast.StmtBreak) {

pkg/printer/pretty_printer.go

@@ -465,11 +465,11 @@ func (p *PrettyPrinter) printNodeNullable(n ast.Vertex) {
 func (p *PrettyPrinter) printNodeArgument(n ast.Vertex) {
 	nn := n.(*ast.Argument)
 
-	if nn.IsReference {
+	if nn.AmpersandTkn != nil {
 		io.WriteString(p.w, "&")
 	}
 
-	if nn.Variadic {
+	if nn.VariadicTkn != nil {
 		io.WriteString(p.w, "...")
 	}
 

pkg/printer/printer.go

@@ -561,12 +561,12 @@ func (p *Printer) printNodeArgument(n ast.Vertex) {
 	nn := n.(*ast.Argument)
 	p.printFreeFloating(nn, token.Start)
 
-	if nn.IsReference {
+	if nn.AmpersandTkn != nil {
 		p.write([]byte("&"))
 	}
 	p.printFreeFloating(nn, token.Ampersand)
 
-	if nn.Variadic {
+	if nn.VariadicTkn != nil {
 		p.write([]byte("..."))
 	}