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Merge pull request #2538 from t-gergely/patch-1 

Update tree-matching.md
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Terence Parr 2020-11-24 10:41:53 -08:00 committed by GitHub
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@ -52,15 +52,6 @@ m.setDelimiters("<<", ">>", "$"); // $ is the escape character
This would allow pattern `<<ID>> = <<expr>> ;$<< ick $>>` to be interpreted as elements: `ID`, ` = `, `expr`, and ` ;<< ick >>`.
```java
String xpath = "//blockStatement/*";
String treePattern = "int <Identifier> = <expression>;";
ParseTreePattern p =
parser.compileParseTreePattern(treePattern,
JavaParser.RULE_localVariableDeclarationStatement);
List<ParseTreeMatch> matches = p.findAll(tree, xpath);
```
### Pattern labels
The tree pattern matcher tracks the nodes in the tree at matches against the tags in a tree pattern. That way we can use the `get()` and `getAll()` methods to retrieve components of the matched subtree. For example, for pattern `<ID>`, `get("ID")` returns the node matched for that `ID`. If more than one node matched the specified token or rule tag, only the first match is returned. If there is no node associated with the label, this returns null.