LabelDereference (trino-parser 358 API)

java.lang.Object
- io.trino.sql.tree.Node
- - io.trino.sql.tree.Expression
  - - io.trino.sql.tree.LabelDereference

```
public class LabelDereference
extends Expression
```
A temporary IR representation of a label-prefixed column reference in the context of row pattern recognition.
It is created from a DereferenceExpression when the MEASURES or DEFINE expressions are rewritten using the TranslationMap: A.price -> DereferenceExpression("A", "price") -> LabelDereference("A", price_symbol). Next, the LabelDereference is processed by the LogicalIndexExtractor, and it is removed from the expression.
LabelDereference is a synthetic AST node. It had to be introduced in order to carry the rewritten symbol (`price_symbol` in the example). The DereferenceExpression cannot be used for that purpose, because it only contains identifiers, and a Symbol cannot be safely converted to an Identifier.

Constructor Summary

Constructors
Constructor Description

LabelDereference(String label, SymbolReference reference)

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`<R,C> R`	`accept(AstVisitor<R,C> visitor, C context)`	Accessible for `AstVisitor`, use `AstVisitor.process(Node, Object)` instead.
`boolean`	`equals(Object o)`
`List<Node>`	`getChildren()`
`String`	`getLabel()`
`SymbolReference`	`getReference()`
`int`	`hashCode()`

Methods inherited from class io.trino.sql.tree.Expression
toString

Methods inherited from class io.trino.sql.tree.Node
getLocation, shallowEquals

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

LabelDereference

public LabelDereference(String label,
                        SymbolReference reference)

Method Detail
- getLabel
```
public String getLabel()
```
- getReference
```
public SymbolReference getReference()
```
- accept
```
public <R,C> R accept(AstVisitor<R,C> visitor,
                            C context)
```
  Description copied from class: Expression
  
  Accessible for AstVisitor, use AstVisitor.process(Node, Object) instead.
  
  Overrides:
  
  accept in class Expression
- getChildren
```
public List<Node> getChildren()
```
  Specified by:
  
  getChildren in class Node
- equals
```
public boolean equals(Object o)
```
  Specified by:
  
  equals in class Node
- hashCode
```
public int hashCode()
```
  Specified by:
  
  hashCode in class Node