org.antlr.runtime.debug

Class DebugTreeNodeStream

java.lang.Object

org.antlr.runtime.debug.DebugTreeNodeStream

All Implemented Interfaces:

IntStream, TreeNodeStream

public class DebugTreeNodeStream
extends Object
implements TreeNodeStream

Debug any tree node stream. The constructor accepts the stream and a debug listener. As node stream calls come in, debug events are triggered.

Field Summary

Fields

Modifier and Type	Field and Description
protected TreeAdaptor	adaptor
protected DebugEventListener	dbg
protected boolean	initialStreamState
protected TreeNodeStream	input
protected int	lastMarker Track the last mark() call result value for use in rewind().

Constructor Summary

Constructors

Constructor and Description
DebugTreeNodeStream(TreeNodeStream input, DebugEventListener dbg)

Method Summary

Methods

Modifier and Type	Method and Description
void	consume()
Object	get(int i) Get a tree node at an absolute index i; 0..n-1.
String	getSourceName() Where are you getting symbols from? Normally, implementations will pass the buck all the way to the lexer who can ask its input stream for the file name or whatever.
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.
int	index() Return the current input symbol index 0..n where n indicates the last symbol has been read.
int	LA(int i) Get int at current input pointer + i ahead where i=1 is next int.
Object	LT(int i) Get tree node at current input pointer + k ahead where k==1 is next node.
int	mark() Tell the stream to start buffering if it hasn't already.
void	release(int marker) You may want to commit to a backtrack but don't want to force the stream to keep bookkeeping objects around for a marker that is no longer necessary.
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	rewind() Rewind to the input position of the last marker.
void	rewind(int marker) Reset the stream so that next call to index would return marker.
void	seek(int index) Set the input cursor to the position indicated by index.
void	setDebugListener(DebugEventListener dbg)
void	setUniqueNavigationNodes(boolean uniqueNavigationNodes) It is normally this object that instructs the node stream to create unique nav nodes, but to satisfy interface, we have to define it.
int	size() Only makes sense for streams that buffer everything up probably, but might be useful to display the entire stream or for testing.
String	toString(Object start, Object stop) Return the text of all nodes from start to stop, inclusive.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

dbg

protected DebugEventListener dbg

adaptor

protected TreeAdaptor adaptor

input

protected TreeNodeStream input

initialStreamState

protected boolean initialStreamState

lastMarker

protected int lastMarker

Track the last mark() call result value for use in rewind().

Constructor Detail

DebugTreeNodeStream

public DebugTreeNodeStream(TreeNodeStream input,
                   DebugEventListener dbg)

Method Detail

setDebugListener

public void setDebugListener(DebugEventListener dbg)

getTreeAdaptor

public TreeAdaptor getTreeAdaptor()

Description copied from interface: TreeNodeStream

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

Specified by:

getTreeAdaptor in interface TreeNodeStream

consume

public void consume()

Specified by:

consume in interface IntStream

get

public Object get(int i)

Description copied from interface: TreeNodeStream

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.

Specified by:

get in interface TreeNodeStream

LT

public Object LT(int i)

Description copied from interface: TreeNodeStream

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.

Specified by:

LT in interface TreeNodeStream

LA

public int LA(int i)

Description copied from interface: IntStream

Get int at current input pointer + i ahead where i=1 is next int. Negative indexes are allowed. LA(-1) is previous token (token just matched). LA(-i) where i is before first token should yield -1, invalid char / EOF.

Specified by:

LA in interface IntStream

mark

public int mark()

Description copied from interface: IntStream

Tell the stream to start buffering if it hasn't already. Return current input position, index(), or some other marker so that when passed to rewind() you get back to the same spot. rewind(mark()) should not affect the input cursor. The Lexer track line/col info as well as input index so its markers are not pure input indexes. Same for tree node streams.

Specified by:

mark in interface IntStream

index

public int index()

Description copied from interface: IntStream

Return the current input symbol index 0..n where n indicates the last symbol has been read. The index is the symbol about to be read not the most recently read symbol.

Specified by:

index in interface IntStream

rewind

public void rewind(int marker)

Description copied from interface: IntStream

Reset the stream so that next call to index would return marker. The marker will usually be index() but it doesn't have to be. It's just a marker to indicate what state the stream was in. This is essentially calling release() and seek(). If there are markers created after this marker argument, this routine must unroll them like a stack. Assume the state the stream was in when this marker was created.

Specified by:

rewind in interface IntStream

rewind

public void rewind()

Description copied from interface: IntStream

Rewind to the input position of the last marker. Used currently only after a cyclic DFA and just before starting a sem/syn predicate to get the input position back to the start of the decision. Do not "pop" the marker off the state. mark(i) and rewind(i) should balance still. It is like invoking rewind(last marker) but it should not "pop" the marker off. It's like seek(last marker's input position).

Specified by:

rewind in interface IntStream

release

public void release(int marker)

Description copied from interface: IntStream

You may want to commit to a backtrack but don't want to force the stream to keep bookkeeping objects around for a marker that is no longer necessary. This will have the same behavior as rewind() except it releases resources without the backward seek. This must throw away resources for all markers back to the marker argument. So if you're nested 5 levels of mark(), and then release(2) you have to release resources for depths 2..5.

Specified by:

release in interface IntStream

seek

public void seek(int index)

Description copied from interface: IntStream

Set the input cursor to the position indicated by index. This is normally used to seek ahead in the input stream. No buffering is required to do this unless you know your stream will use seek to move backwards such as when backtracking. This is different from rewind in its multi-directional requirement and in that its argument is strictly an input cursor (index). For char streams, seeking forward must update the stream state such as line number. For seeking backwards, you will be presumably backtracking using the mark/rewind mechanism that restores state and so this method does not need to update state when seeking backwards. Currently, this method is only used for efficient backtracking using memoization, but in the future it may be used for incremental parsing. The index is 0..n-1. A seek to position i means that LA(1) will return the ith symbol. So, seeking to 0 means LA(1) will return the first element in the stream.

Specified by:

seek in interface IntStream

size

public int size()

Description copied from interface: IntStream

Only makes sense for streams that buffer everything up probably, but might be useful to display the entire stream or for testing. This value includes a single EOF.

Specified by:

size in interface IntStream

reset

public void reset()

Description copied from interface: TreeNodeStream

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

Specified by:

reset in interface TreeNodeStream

getTreeSource

public Object getTreeSource()

Description copied from interface: TreeNodeStream

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

Specified by:

getTreeSource in interface TreeNodeStream

getSourceName

public String getSourceName()

Description copied from interface: IntStream

Where are you getting symbols from? Normally, implementations will pass the buck all the way to the lexer who can ask its input stream for the file name or whatever.

Specified by:

getSourceName in interface IntStream

getTokenStream

public TokenStream getTokenStream()

Description copied from interface: TreeNodeStream

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.

Specified by:

getTokenStream in interface TreeNodeStream

setUniqueNavigationNodes

public void setUniqueNavigationNodes(boolean uniqueNavigationNodes)

It is normally this object that instructs the node stream to create unique nav nodes, but to satisfy interface, we have to define it. It might be better to ignore the parameter but there might be a use for it later, so I'll leave.

Specified by:

setUniqueNavigationNodes in interface TreeNodeStream

replaceChildren

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

Description copied from interface: TreeNodeStream

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.

Specified by:

replaceChildren in interface TreeNodeStream

toString

public String toString(Object start,
              Object stop)

Description copied from interface: TreeNodeStream

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.

Specified by:

toString in interface TreeNodeStream