org.antlr.runtime.tree

Interface TreeNodeStream

All Superinterfaces:

IntStream

All Known Implementing Classes:

BufferedTreeNodeStream, CommonTreeNodeStream, DebugTreeNodeStream

public interface TreeNodeStream
extends IntStream

A stream of tree nodes, accessing nodes from a tree of some kind

Method Summary

Methods

Modifier and Type	Method and Description
Object	get(int i) Get a tree node at an absolute index i; 0..n-1.
TokenStream	getTokenStream() If the tree associated with this stream was created from a TokenStream, you can specify it here.
TreeAdaptor	getTreeAdaptor() What adaptor can tell me how to interpret/navigate nodes and trees.
Object	getTreeSource() Where is this stream pulling nodes from? This is not the name, but the object that provides node objects.
Object	LT(int k) Get tree node at current input pointer + k ahead where k==1 is next node.
void	replaceChildren(Object parent, int startChildIndex, int stopChildIndex, Object t) Replace children of parent from index startChildIndex to stopChildIndex with t, which might be a list.
void	reset() Reset the tree node stream in such a way that it acts like a freshly constructed stream.
void	setUniqueNavigationNodes(boolean uniqueNavigationNodes) As we flatten the tree, we use Token.UP, Token.DOWN nodes to represent the tree structure.
String	toString(Object start, Object stop) Return the text of all nodes from start to stop, inclusive.

Methods inherited from interface org.antlr.runtime.IntStream

consume, getSourceName, index, LA, mark, release, rewind, rewind, seek, size

Method Detail

get

Object get(int i)

Get a tree node at an absolute index i; 0..n-1. If you don't want to buffer up nodes, then this method makes no sense for you.

LT

Object LT(int k)

Get tree node at current input pointer + k ahead where k==1 is next node. k<0 indicates nodes in the past. So LT(-1) is previous node, but implementations are not required to provide results for k < -1. LT(0) is undefined. For k<=n, return null. Return null for LT(0) and any index that results in an absolute address that is negative.

This is analogous to TokenStream.LT(int), but this returns a tree node instead of a Token. Makes code generation identical for both parser and tree grammars.

getTreeSource

Object getTreeSource()

Where is this stream pulling nodes from? This is not the name, but the object that provides node objects.

getTokenStream

TokenStream getTokenStream()

If the tree associated with this stream was created from a TokenStream, you can specify it here. Used to do rule $text attribute in tree parser. Optional unless you use tree parser rule $text attribute or output=template and rewrite=true options.

getTreeAdaptor

TreeAdaptor getTreeAdaptor()

What adaptor can tell me how to interpret/navigate nodes and trees. E.g., get text of a node.

setUniqueNavigationNodes

void setUniqueNavigationNodes(boolean uniqueNavigationNodes)

As we flatten the tree, we use Token.UP, Token.DOWN nodes to represent the tree structure. When debugging we need unique nodes so we have to instantiate new ones. When doing normal tree parsing, it's slow and a waste of memory to create unique navigation nodes. Default should be false.

reset

void reset()

Reset the tree node stream in such a way that it acts like a freshly constructed stream.

toString

String toString(Object start,
              Object stop)

Return the text of all nodes from start to stop, inclusive. If the stream does not buffer all the nodes then it can still walk recursively from start until stop. You can always return null or "" too, but users should not access $ruleLabel.text in an action of course in that case.

replaceChildren

void replaceChildren(Object parent,
                   int startChildIndex,
                   int stopChildIndex,
                   Object t)

Replace children of parent from index startChildIndex to stopChildIndex with t, which might be a list. Number of children may be different after this call. The stream is notified because it is walking the tree and might need to know you are monkeying with the underlying tree. Also, it might be able to modify the node stream to avoid restreaming for future phases.

If parent is null, don't do anything; must be at root of overall tree. Can't replace whatever points to the parent externally. Do nothing.