Tree

The basic notion of a tree has a parent, a payload, and a list of children. It is the most abstract interface for all the trees used by ANTLR.

interface Tree {

Tree getParent();

Object getPayload();

Tree getChild(int i);

int getChildCount();

string toStringTree();

}

Members

Functions

getChild Tree getChild(int i): If there are children, get the {@code i}th value indexed from 0.
getChildCount int getChildCount(): How many children are there? If there is none, then this node represents a leaf node.
getParent Tree getParent(): The parent of this node. If the return value is null, then this node is the root of the tree.
getPayload Object getPayload(): This method returns whatever object represents the data at this node. For example, for parse trees, the payload can be a {@link Token} representing a leaf node or a {@link RuleContext} object representing a rule invocation. For abstract syntax trees (ASTs), this is a {@link Token} object.
toStringTree string toStringTree(): Print out a whole tree, not just a node, in LISP format {@code (root child1 .. childN)}. Print just a node if this is a leaf.

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Source

See Implementation