Module jdk.scripting.nashorn
Package jdk.nashorn.api.tree

## Interface TreeVisitor<R,​P>

- Type Parameters:
    `R` - the return type of this visitor's methods. Use `Void` for visitors that do not need to return results.
    `P` - the type of the additional parameter to this visitor's methods. Use `Void` for visitors that do not need an additional parameter.
  All Known Implementing Classes:
    `SimpleTreeVisitorES5_1`, `SimpleTreeVisitorES6`

      @Deprecated(since="11",
                  forRemoval=true)
      public interface TreeVisitor<R,​P>

  Deprecated, for removal: This API element is subject to removal in a future version.
  Nashorn JavaScript script engine and APIs, and the jjs tool are deprecated with the intent to remove them in a future release.
  A visitor of trees, in the style of the visitor design pattern. Classes implementing this interface are used to operate on a tree when the kind of tree is unknown at compile time. When a visitor is passed to an tree's `accept` method, the `visitXyz` method most applicable to that tree is invoked.

  Classes implementing this interface may or may not throw a `NullPointerException` if the additional parameter `p` is `null`; see documentation of the implementing class for details.

  WARNING: It is possible that methods will be added to this interface to accommodate new, currently unknown, language structures added to future versions of the ECMAScript programming language. When new visit methods are added for new Tree subtypes, default method bodies will be introduced which will call visitUnknown method as a fallback.

  Since:
    9

- - ### Method Summary

    All Methods Instance Methods Abstract Methods Deprecated Methods
    Modifier and Type | Method | Description
    --- | --- | ---
    `R` | `visitArrayAccess​(ArrayAccessTree node, P p)` | Deprecated, for removal: This API element is subject to removal in a future version. Visit array access expression tree.
    `R` | `visitArrayLiteral​(ArrayLiteralTree node, P p)` | Deprecated, for removal: This API element is subject to removal in a future version. Visit array literal expression tree.
    `R` | `visitAssignment​(AssignmentTree node, P p)` | Deprecated, for removal: This API element is subject to removal in a future version. Visit assignment tree.
    `R` | `visitBinary​(BinaryTree node, P p)` | Deprecated, for removal: This API element is subject to removal in a future version. Visit binary expression tree.
    `R` | `visitBlock​(BlockTree node, P p)` | Deprecated, for removal: This API element is subject to removal in a future version. Visit block statement tree.
    `R` | `visitBreak​(BreakTree node, P p)` | Deprecated, for removal: This API element is subject to removal in a future version. Visit break statement tree.
    `R` | `visitCase​(CaseTree node, P p)` | Deprecated, for removal: This API element is subject to removal in a future version. Visit case statement tree.
    `R` | `visitCatch​(CatchTree node, P p)` | Deprecated, for removal: This API element is subject to removal in a future version. Visit catch block statement tree.
    `R` | `visitClassDeclaration​(ClassDeclarationTree node, P p)` | Deprecated, for removal: This API element is subject to removal in a future version. Visit class statement tree.
    `R` | `visitClassExpression​(ClassExpressionTree node, P p)` | Deprecated, for removal: This API element is subject to removal in a future version. Visit class expression tree.
    `R` | `visitCompilationUnit​(CompilationUnitTree node, P p)` | Deprecated, for removal: This API element is subject to removal in a future version. Visit compilation unit tree.
    `R` | `visitCompoundAssignment​(CompoundAssignmentTree node, P p)` | Deprecated, for removal: This API element is subject to removal in a future version. Visit compound assignment tree.
    `R` | `visitConditionalExpression​(ConditionalExpressionTree node, P p)` | Deprecated, for removal: This API element is subject to removal in a future version. Visit conditional expression tree.
    `R` | `visitContinue​(ContinueTree node, P p)` | Deprecated, for removal: This API element is subject to removal in a future version. Visit continue statement tree.
    `R` | `visitDebugger​(DebuggerTree node, P p)` | Deprecated, for removal: This API element is subject to removal in a future version. Visit debugger statement tree.
    `R` | `visitDoWhileLoop​(DoWhileLoopTree node, P p)` | Deprecated, for removal: This API element is subject to removal in a future version. Visit do-while statement tree.
    `R` | `visitEmptyStatement​(EmptyStatementTree node, P p)` | Deprecated, for removal: This API element is subject to removal in a future version. Visit an empty statement tree.
    `R` | `visitErroneous​(ErroneousTree node, P p)` | Deprecated, for removal: This API element is subject to removal in a future version. Visit error expression tree.
    `R` | `visitExportEntry​(ExportEntryTree node, P p)` | Deprecated, for removal: This API element is subject to removal in a future version. Visit Module ExportEntry tree.
    `R` | `visitExpressionStatement​(ExpressionStatementTree node, P p)` | Deprecated, for removal: This API element is subject to removal in a future version. Visit expression statement tree.
    `R` | `visitForInLoop​(ForInLoopTree node, P p)` | Deprecated, for removal: This API element is subject to removal in a future version. Visit for..in statement tree.
    `R` | `visitForLoop​(ForLoopTree node, P p)` | Deprecated, for removal: This API element is subject to removal in a future version. Visit 'for' statement tree.
    `R` | `visitForOfLoop​(ForOfLoopTree node, P p)` | Deprecated, for removal: This API element is subject to removal in a future version. Visit for..of statement tree.
    `R` | `visitFunctionCall​(FunctionCallTree node, P p)` | Deprecated, for removal: This API element is subject to removal in a future version. Visit function call expression tree.
    `R` | `visitFunctionDeclaration​(FunctionDeclarationTree node, P p)` | Deprecated, for removal: This API element is subject to removal in a future version. Visit function declaration tree.
    `R` | `visitFunctionExpression​(FunctionExpressionTree node, P p)` | Deprecated, for removal: This API element is subject to removal in a future version. Visit function expression tree.
    `R` | `visitIdentifier​(IdentifierTree node, P p)` | Deprecated, for removal: This API element is subject to removal in a future version. Visit identifier tree.
    `R` | `visitIf​(IfTree node, P p)` | Deprecated, for removal: This API element is subject to removal in a future version. Visit 'if' statement tree.
    `R` | `visitImportEntry​(ImportEntryTree node, P p)` | Deprecated, for removal: This API element is subject to removal in a future version. Visit Module ImportEntry tree.
    `R` | `visitInstanceOf​(InstanceOfTree node, P p)` | Deprecated, for removal: This API element is subject to removal in a future version. Visit 'instanceof' expression tree.
    `R` | `visitLabeledStatement​(LabeledStatementTree node, P p)` | Deprecated, for removal: This API element is subject to removal in a future version. Visit labeled statement tree.
    `R` | `visitLiteral​(LiteralTree node, P p)` | Deprecated, for removal: This API element is subject to removal in a future version. Visit literal expression tree.
    `R` | `visitMemberSelect​(MemberSelectTree node, P p)` | Deprecated, for removal: This API element is subject to removal in a future version. Visit member select expression tree.
    `R` | `visitModule​(ModuleTree node, P p)` | Deprecated, for removal: This API element is subject to removal in a future version. Visit Module tree.
    `R` | `visitNew​(NewTree node, P p)` | Deprecated, for removal: This API element is subject to removal in a future version. Visit 'new' expression tree.
    `R` | `visitObjectLiteral​(ObjectLiteralTree node, P p)` | Deprecated, for removal: This API element is subject to removal in a future version. Visit object literal tree.
    `R` | `visitParenthesized​(ParenthesizedTree node, P p)` | Deprecated, for removal: This API element is subject to removal in a future version. Visit parenthesized expression tree.
    `R` | `visitProperty​(PropertyTree node, P p)` | Deprecated, for removal: This API element is subject to removal in a future version. Visit a property of an object literal expression tree.
    `R` | `visitRegExpLiteral​(RegExpLiteralTree node, P p)` | Deprecated, for removal: This API element is subject to removal in a future version. Visit regular expression literal tree.
    `R` | `visitReturn​(ReturnTree node, P p)` | Deprecated, for removal: This API element is subject to removal in a future version. Visit return statement tree.
    `R` | `visitSpread​(SpreadTree node, P p)` | Deprecated, for removal: This API element is subject to removal in a future version. Visit 'spread' expression tree.
    `R` | `visitSwitch​(SwitchTree node, P p)` | Deprecated, for removal: This API element is subject to removal in a future version. Visit 'switch' statement tree.
    `R` | `visitTemplateLiteral​(TemplateLiteralTree node, P p)` | Deprecated, for removal: This API element is subject to removal in a future version. Visit template literal tree.
    `R` | `visitThrow​(ThrowTree node, P p)` | Deprecated, for removal: This API element is subject to removal in a future version. Visit 'throw' expression tree.
    `R` | `visitTry​(TryTree node, P p)` | Deprecated, for removal: This API element is subject to removal in a future version. Visit 'try' statement tree.
    `R` | `visitUnary​(UnaryTree node, P p)` | Deprecated, for removal: This API element is subject to removal in a future version. Visit unary expression tree.
    `R` | `visitUnknown​(Tree node, P p)` | Deprecated, for removal: This API element is subject to removal in a future version. Visit unknown expression/statement tree.
    `R` | `visitVariable​(VariableTree node, P p)` | Deprecated, for removal: This API element is subject to removal in a future version. Visit variable declaration tree.
    `R` | `visitWhileLoop​(WhileLoopTree node, P p)` | Deprecated, for removal: This API element is subject to removal in a future version. Visit 'while' statement tree.
    `R` | `visitWith​(WithTree node, P p)` | Deprecated, for removal: This API element is subject to removal in a future version. Visit 'with' statement tree.
    `R` | `visitYield​(YieldTree node, P p)` | Deprecated, for removal: This API element is subject to removal in a future version. Visit 'yield' expression tree.

- - ### Method Detail

    - #### visitAssignment

          R visitAssignment​(AssignmentTree node,
                            P p)

      Deprecated, for removal: This API element is subject to removal in a future version.
      Visit assignment tree.
      Parameters:
        `node` - node being visited
        `p` - extra parameter passed to the visitor
      Returns:
        value from the visitor

    - #### visitCompoundAssignment

          R visitCompoundAssignment​(CompoundAssignmentTree node,
                                    P p)

      Deprecated, for removal: This API element is subject to removal in a future version.
      Visit compound assignment tree.
      Parameters:
        `node` - node being visited
        `p` - extra parameter passed to the visitor
      Returns:
        value from the visitor

    - #### visitBinary

          R visitBinary​(BinaryTree node,
                        P p)

      Deprecated, for removal: This API element is subject to removal in a future version.
      Visit binary expression tree.
      Parameters:
        `node` - node being visited
        `p` - extra parameter passed to the visitor
      Returns:
        value from the visitor

    - #### visitBlock

          R visitBlock​(BlockTree node,
                       P p)

      Deprecated, for removal: This API element is subject to removal in a future version.
      Visit block statement tree.
      Parameters:
        `node` - node being visited
        `p` - extra parameter passed to the visitor
      Returns:
        value from the visitor

    - #### visitBreak

          R visitBreak​(BreakTree node,
                       P p)

      Deprecated, for removal: This API element is subject to removal in a future version.
      Visit break statement tree.
      Parameters:
        `node` - node being visited
        `p` - extra parameter passed to the visitor
      Returns:
        value from the visitor

    - #### visitCase

          R visitCase​(CaseTree node,
                      P p)

      Deprecated, for removal: This API element is subject to removal in a future version.
      Visit case statement tree.
      Parameters:
        `node` - node being visited
        `p` - extra parameter passed to the visitor
      Returns:
        value from the visitor

    - #### visitCatch

          R visitCatch​(CatchTree node,
                       P p)

      Deprecated, for removal: This API element is subject to removal in a future version.
      Visit catch block statement tree.
      Parameters:
        `node` - node being visited
        `p` - extra parameter passed to the visitor
      Returns:
        value from the visitor

    - #### visitClassDeclaration

          R visitClassDeclaration​(ClassDeclarationTree node,
                                  P p)

      Deprecated, for removal: This API element is subject to removal in a future version.
      Visit class statement tree.
      Parameters:
        `node` - node being visited
        `p` - extra parameter passed to the visitor
      Returns:
        value from the visitor

    - #### visitClassExpression

          R visitClassExpression​(ClassExpressionTree node,
                                 P p)

      Deprecated, for removal: This API element is subject to removal in a future version.
      Visit class expression tree.
      Parameters:
        `node` - node being visited
        `p` - extra parameter passed to the visitor
      Returns:
        value from the visitor

    - #### visitConditionalExpression

          R visitConditionalExpression​(ConditionalExpressionTree node,
                                       P p)

      Deprecated, for removal: This API element is subject to removal in a future version.
      Visit conditional expression tree.
      Parameters:
        `node` - node being visited
        `p` - extra parameter passed to the visitor
      Returns:
        value from the visitor

    - #### visitContinue

          R visitContinue​(ContinueTree node,
                          P p)

      Deprecated, for removal: This API element is subject to removal in a future version.
      Visit continue statement tree.
      Parameters:
        `node` - node being visited
        `p` - extra parameter passed to the visitor
      Returns:
        value from the visitor

    - #### visitDebugger

          R visitDebugger​(DebuggerTree node,
                          P p)

      Deprecated, for removal: This API element is subject to removal in a future version.
      Visit debugger statement tree.
      Parameters:
        `node` - node being visited
        `p` - extra parameter passed to the visitor
      Returns:
        value from the visitor

    - #### visitDoWhileLoop

          R visitDoWhileLoop​(DoWhileLoopTree node,
                             P p)

      Deprecated, for removal: This API element is subject to removal in a future version.
      Visit do-while statement tree.
      Parameters:
        `node` - node being visited
        `p` - extra parameter passed to the visitor
      Returns:
        value from the visitor

    - #### visitErroneous

          R visitErroneous​(ErroneousTree node,
                           P p)

      Deprecated, for removal: This API element is subject to removal in a future version.
      Visit error expression tree.
      Parameters:
        `node` - node being visited
        `p` - extra parameter passed to the visitor
      Returns:
        value from the visitor

    - #### visitExpressionStatement

          R visitExpressionStatement​(ExpressionStatementTree node,
                                     P p)

      Deprecated, for removal: This API element is subject to removal in a future version.
      Visit expression statement tree.
      Parameters:
        `node` - node being visited
        `p` - extra parameter passed to the visitor
      Returns:
        value from the visitor

    - #### visitForLoop

          R visitForLoop​(ForLoopTree node,
                         P p)

      Deprecated, for removal: This API element is subject to removal in a future version.
      Visit 'for' statement tree.
      Parameters:
        `node` - node being visited
        `p` - extra parameter passed to the visitor
      Returns:
        value from the visitor

    - #### visitForInLoop

          R visitForInLoop​(ForInLoopTree node,
                           P p)

      Deprecated, for removal: This API element is subject to removal in a future version.
      Visit for..in statement tree.
      Parameters:
        `node` - node being visited
        `p` - extra parameter passed to the visitor
      Returns:
        value from the visitor

    - #### visitForOfLoop

          R visitForOfLoop​(ForOfLoopTree node,
                           P p)

      Deprecated, for removal: This API element is subject to removal in a future version.
      Visit for..of statement tree.
      Parameters:
        `node` - node being visited
        `p` - extra parameter passed to the visitor
      Returns:
        value from the visitor

    - #### visitFunctionCall

          R visitFunctionCall​(FunctionCallTree node,
                              P p)

      Deprecated, for removal: This API element is subject to removal in a future version.
      Visit function call expression tree.
      Parameters:
        `node` - node being visited
        `p` - extra parameter passed to the visitor
      Returns:
        value from the visitor

    - #### visitFunctionDeclaration

          R visitFunctionDeclaration​(FunctionDeclarationTree node,
                                     P p)

      Deprecated, for removal: This API element is subject to removal in a future version.
      Visit function declaration tree.
      Parameters:
        `node` - node being visited
        `p` - extra parameter passed to the visitor
      Returns:
        value from the visitor

    - #### visitFunctionExpression

          R visitFunctionExpression​(FunctionExpressionTree node,
                                    P p)

      Deprecated, for removal: This API element is subject to removal in a future version.
      Visit function expression tree.
      Parameters:
        `node` - node being visited
        `p` - extra parameter passed to the visitor
      Returns:
        value from the visitor

    - #### visitIdentifier

          R visitIdentifier​(IdentifierTree node,
                            P p)

      Deprecated, for removal: This API element is subject to removal in a future version.
      Visit identifier tree.
      Parameters:
        `node` - node being visited
        `p` - extra parameter passed to the visitor
      Returns:
        value from the visitor

    - #### visitIf

          R visitIf​(IfTree node,
                    P p)

      Deprecated, for removal: This API element is subject to removal in a future version.
      Visit 'if' statement tree.
      Parameters:
        `node` - node being visited
        `p` - extra parameter passed to the visitor
      Returns:
        value from the visitor

    - #### visitArrayAccess

          R visitArrayAccess​(ArrayAccessTree node,
                             P p)

      Deprecated, for removal: This API element is subject to removal in a future version.
      Visit array access expression tree.
      Parameters:
        `node` - node being visited
        `p` - extra parameter passed to the visitor
      Returns:
        value from the visitor

    - #### visitArrayLiteral

          R visitArrayLiteral​(ArrayLiteralTree node,
                              P p)

      Deprecated, for removal: This API element is subject to removal in a future version.
      Visit array literal expression tree.
      Parameters:
        `node` - node being visited
        `p` - extra parameter passed to the visitor
      Returns:
        value from the visitor

    - #### visitLabeledStatement

          R visitLabeledStatement​(LabeledStatementTree node,
                                  P p)

      Deprecated, for removal: This API element is subject to removal in a future version.
      Visit labeled statement tree.
      Parameters:
        `node` - node being visited
        `p` - extra parameter passed to the visitor
      Returns:
        value from the visitor

    - #### visitLiteral

          R visitLiteral​(LiteralTree node,
                         P p)

      Deprecated, for removal: This API element is subject to removal in a future version.
      Visit literal expression tree.
      Parameters:
        `node` - node being visited
        `p` - extra parameter passed to the visitor
      Returns:
        value from the visitor

    - #### visitParenthesized

          R visitParenthesized​(ParenthesizedTree node,
                               P p)

      Deprecated, for removal: This API element is subject to removal in a future version.
      Visit parenthesized expression tree.
      Parameters:
        `node` - node being visited
        `p` - extra parameter passed to the visitor
      Returns:
        value from the visitor

    - #### visitReturn

          R visitReturn​(ReturnTree node,
                        P p)

      Deprecated, for removal: This API element is subject to removal in a future version.
      Visit return statement tree.
      Parameters:
        `node` - node being visited
        `p` - extra parameter passed to the visitor
      Returns:
        value from the visitor

    - #### visitMemberSelect

          R visitMemberSelect​(MemberSelectTree node,
                              P p)

      Deprecated, for removal: This API element is subject to removal in a future version.
      Visit member select expression tree.
      Parameters:
        `node` - node being visited
        `p` - extra parameter passed to the visitor
      Returns:
        value from the visitor

    - #### visitNew

          R visitNew​(NewTree node,
                     P p)

      Deprecated, for removal: This API element is subject to removal in a future version.
      Visit 'new' expression tree.
      Parameters:
        `node` - node being visited
        `p` - extra parameter passed to the visitor
      Returns:
        value from the visitor

    - #### visitObjectLiteral

          R visitObjectLiteral​(ObjectLiteralTree node,
                               P p)

      Deprecated, for removal: This API element is subject to removal in a future version.
      Visit object literal tree.
      Parameters:
        `node` - node being visited
        `p` - extra parameter passed to the visitor
      Returns:
        value from the visitor

    - #### visitProperty

          R visitProperty​(PropertyTree node,
                          P p)

      Deprecated, for removal: This API element is subject to removal in a future version.
      Visit a property of an object literal expression tree.
      Parameters:
        `node` - node being visited
        `p` - extra parameter passed to the visitor
      Returns:
        value from the visitor

    - #### visitRegExpLiteral

          R visitRegExpLiteral​(RegExpLiteralTree node,
                               P p)

      Deprecated, for removal: This API element is subject to removal in a future version.
      Visit regular expression literal tree.
      Parameters:
        `node` - node being visited
        `p` - extra parameter passed to the visitor
      Returns:
        value from the visitor

    - #### visitTemplateLiteral

          R visitTemplateLiteral​(TemplateLiteralTree node,
                                 P p)

      Deprecated, for removal: This API element is subject to removal in a future version.
      Visit template literal tree.
      Parameters:
        `node` - node being visited
        `p` - extra parameter passed to the visitor
      Returns:
        value from the visitor

    - #### visitEmptyStatement

          R visitEmptyStatement​(EmptyStatementTree node,
                                P p)

      Deprecated, for removal: This API element is subject to removal in a future version.
      Visit an empty statement tree.
      Parameters:
        `node` - node being visited
        `p` - extra parameter passed to the visitor
      Returns:
        value from the visitor

    - #### visitSpread

          R visitSpread​(SpreadTree node,
                        P p)

      Deprecated, for removal: This API element is subject to removal in a future version.
      Visit 'spread' expression tree.
      Parameters:
        `node` - node being visited
        `p` - extra parameter passed to the visitor
      Returns:
        value from the visitor

    - #### visitSwitch

          R visitSwitch​(SwitchTree node,
                        P p)

      Deprecated, for removal: This API element is subject to removal in a future version.
      Visit 'switch' statement tree.
      Parameters:
        `node` - node being visited
        `p` - extra parameter passed to the visitor
      Returns:
        value from the visitor

    - #### visitThrow

          R visitThrow​(ThrowTree node,
                       P p)

      Deprecated, for removal: This API element is subject to removal in a future version.
      Visit 'throw' expression tree.
      Parameters:
        `node` - node being visited
        `p` - extra parameter passed to the visitor
      Returns:
        value from the visitor

    - #### visitCompilationUnit

          R visitCompilationUnit​(CompilationUnitTree node,
                                 P p)

      Deprecated, for removal: This API element is subject to removal in a future version.
      Visit compilation unit tree.
      Parameters:
        `node` - node being visited
        `p` - extra parameter passed to the visitor
      Returns:
        value from the visitor

    - #### visitModule

          R visitModule​(ModuleTree node,
                        P p)

      Deprecated, for removal: This API element is subject to removal in a future version.
      Visit Module tree.
      Parameters:
        `node` - node being visited
        `p` - extra parameter passed to the visitor
      Returns:
        value from the visitor

    - #### visitExportEntry

          R visitExportEntry​(ExportEntryTree node,
                             P p)

      Deprecated, for removal: This API element is subject to removal in a future version.
      Visit Module ExportEntry tree.
      Parameters:
        `node` - node being visited
        `p` - extra parameter passed to the visitor
      Returns:
        value from the visitor

    - #### visitImportEntry

          R visitImportEntry​(ImportEntryTree node,
                             P p)

      Deprecated, for removal: This API element is subject to removal in a future version.
      Visit Module ImportEntry tree.
      Parameters:
        `node` - node being visited
        `p` - extra parameter passed to the visitor
      Returns:
        value from the visitor

    - #### visitTry

          R visitTry​(TryTree node,
                     P p)

      Deprecated, for removal: This API element is subject to removal in a future version.
      Visit 'try' statement tree.
      Parameters:
        `node` - node being visited
        `p` - extra parameter passed to the visitor
      Returns:
        value from the visitor

    - #### visitInstanceOf

          R visitInstanceOf​(InstanceOfTree node,
                            P p)

      Deprecated, for removal: This API element is subject to removal in a future version.
      Visit 'instanceof' expression tree.
      Parameters:
        `node` - node being visited
        `p` - extra parameter passed to the visitor
      Returns:
        value from the visitor

    - #### visitUnary

          R visitUnary​(UnaryTree node,
                       P p)

      Deprecated, for removal: This API element is subject to removal in a future version.
      Visit unary expression tree.
      Parameters:
        `node` - node being visited
        `p` - extra parameter passed to the visitor
      Returns:
        value from the visitor

    - #### visitVariable

          R visitVariable​(VariableTree node,
                          P p)

      Deprecated, for removal: This API element is subject to removal in a future version.
      Visit variable declaration tree.
      Parameters:
        `node` - node being visited
        `p` - extra parameter passed to the visitor
      Returns:
        value from the visitor

    - #### visitWhileLoop

          R visitWhileLoop​(WhileLoopTree node,
                           P p)

      Deprecated, for removal: This API element is subject to removal in a future version.
      Visit 'while' statement tree.
      Parameters:
        `node` - node being visited
        `p` - extra parameter passed to the visitor
      Returns:
        value from the visitor

    - #### visitWith

          R visitWith​(WithTree node,
                      P p)

      Deprecated, for removal: This API element is subject to removal in a future version.
      Visit 'with' statement tree.
      Parameters:
        `node` - node being visited
        `p` - extra parameter passed to the visitor
      Returns:
        value from the visitor

    - #### visitYield

          R visitYield​(YieldTree node,
                       P p)

      Deprecated, for removal: This API element is subject to removal in a future version.
      Visit 'yield' expression tree.
      Parameters:
        `node` - node being visited
        `p` - extra parameter passed to the visitor
      Returns:
        value from the visitor

    - #### visitUnknown

          R visitUnknown​(Tree node,
                         P p)

      Deprecated, for removal: This API element is subject to removal in a future version.
      Visit unknown expression/statement tree. This fallback will be called if new Tree subtypes are introduced in future. A specific implementation may throw {unknown tree exception if the visitor implementation was for an older language version.
      Parameters:
        `node` - node being visited
        `p` - extra parameter passed to the visitor
      Returns:
        value from the visitor