[refactoring] update ast structure of "Throw" node

internal/php5/php5.y

@@ -1167,15 +1167,14 @@ unticked_statement:
             }
     |   T_THROW expr ';'
             {
-                $$ = &ast.StmtThrow{ast.Node{}, $2}
-
-                // save position
-                $$.GetNode().Position = position.NewTokensPosition($1, $3)
-
-                // save comments
-                yylex.(*Parser).setFreeFloating($$, token.Start, $1.SkippedTokens)
-                yylex.(*Parser).setFreeFloating($$, token.Expr, $3.SkippedTokens)
-                yylex.(*Parser).setToken($$, token.SemiColon, $3.SkippedTokens)
+                $$ = &ast.StmtThrow{
+                    Node: ast.Node{
+                        Position: position.NewTokensPosition($1, $3),
+                    },
+                    ThrowTkn:     $1,
+                    Expr:         $2,
+                    SemiColonTkn: $3,
+                }
             }
     |   T_GOTO T_STRING ';'
             {

internal/php7/php7.y

@@ -1077,15 +1077,14 @@ statement:
             }
     |   T_THROW expr ';'
             {
-                $$ = &ast.StmtThrow{ast.Node{}, $2}
-
-                // save position
-                $$.GetNode().Position = position.NewTokensPosition($1, $3)
-
-                // save comments
-                yylex.(*Parser).setFreeFloating($$, token.Start, $1.SkippedTokens)
-                yylex.(*Parser).setFreeFloating($$, token.Expr, $3.SkippedTokens)
-                yylex.(*Parser).setToken($$, token.SemiColon, $3.SkippedTokens)
+                $$ = &ast.StmtThrow{
+                    Node: ast.Node{
+                        Position: position.NewTokensPosition($1, $3),
+                    },
+                    ThrowTkn:     $1,
+                    Expr:         $2,
+                    SemiColonTkn: $3,
+                }
             }
     |   T_GOTO T_STRING ';'
             {

pkg/ast/node.go

@@ -709,7 +709,9 @@ func (n *StmtSwitch) Accept(v NodeVisitor) {
 // StmtThrow node
 type StmtThrow struct {
 	Node
+	ThrowTkn     *token.Token
 	Expr         Vertex
+	SemiColonTkn *token.Token
 }
 
 func (n *StmtThrow) Accept(v NodeVisitor) {

pkg/ast/visitor/filter_tokens.go

@@ -260,3 +260,8 @@ func (v *FilterTokens) StmtFinally(n *ast.StmtFinally) {
 	n.OpenCurlyBracketTkn = nil
 	n.CloseCurlyBracketTkn = nil
 }
+
+func (v *FilterTokens) StmtThrow(n *ast.StmtThrow) {
+	n.ThrowTkn = nil
+	n.SemiColonTkn = nil
+}

pkg/printer/printer.go

@@ -2674,23 +2674,11 @@ func (p *Printer) printStmtAltSwitch(n *ast.StmtSwitch) {
 	p.printToken(n.SemiColonTkn, ";")
 }
 
-func (p *Printer) printStmtThrow(n ast.Vertex) {
-	nn := n.(*ast.StmtThrow)
-	p.printFreeFloating(nn, token.Start)
-
-	p.write([]byte("throw"))
-	if nn.Expr.GetNode().Tokens.IsEmpty() {
-		p.write([]byte(" "))
-	}
-	p.Print(nn.Expr)
-	p.printFreeFloating(nn, token.Expr)
-
-	p.printFreeFloating(nn, token.SemiColon)
-	if n.GetNode().Tokens.IsEmpty() {
-		p.write([]byte(";"))
-	}
-
-	p.printFreeFloating(nn, token.End)
+func (p *Printer) printStmtThrow(n *ast.StmtThrow) {
+	p.printToken(n.ThrowTkn, "throw")
+	p.bufStart = " "
+	p.Print(n.Expr)
+	p.printToken(n.SemiColonTkn, ";")
 }
 
 func (p *Printer) printStmtTraitAdaptationList(n ast.Vertex) {