Package ch.usi.si.seart.treesitter

Class TreeCursor

java.lang.Object

ch.usi.si.seart.treesitter.TreeCursor

All Implemented Interfaces:

AutoCloseable, Cloneable

Direct Known Subclasses:

OffsetTreeCursor

public class TreeCursor
extends Object
implements Cloneable

A tree cursor is a stateful object that allows you to walk a syntax tree with maximum efficiency. It allows you to walk a syntax tree more efficiently than is possible using the Node traversal functions. It is always on a certain syntax node, and can be moved imperatively to different nodes.

Since:

1.0.0

Author:

Tommy MacWilliam, Ozren Dabić

Method Summary

Modifier and Type	Method	Description
TreeCursor	clone()	Clone this cursor, creating a separate, independent instance.
void	close()	Delete the external resource, freeing all the memory that it used.
boolean	equals(Object obj)
String	getCurrentFieldName()	Get the field name of the Node that the cursor is currently pointing to.
Node	getCurrentNode()	Get the Node that the cursor is currently pointing to.
TreeCursorNode	getCurrentTreeCursorNode()	Get the TreeCursorNode representation of the Node that the cursor is currently pointing to.
boolean	gotoFirstChild()	Move the cursor to the first child of its current node.
boolean	gotoFirstChild(int offset)	Move the cursor to the first child of its current node that extends beyond the given byte offset.
boolean	gotoFirstChild(@NotNull Point point)	Move the cursor to the first child of its current node that extends beyond the given row-column offset.
boolean	gotoNextSibling()	Move the cursor to the next sibling of its current node.
boolean	gotoNode(@NotNull Node node)	Move the cursor to an arbitrary node.
boolean	gotoParent()	Move the cursor to the parent of its current node.
int	hashCode()
boolean	isNull()	Checks whether the memory address associated with this external resource is nullptr.
void	preorderTraversal(@NotNull Consumer<Node> callback)	Iteratively traverse over the parse tree, applying a callback to the nodes before they are visited.

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, toString, wait, wait, wait

Method Detail

getCurrentNode

public Node getCurrentNode()

Get the Node that the cursor is currently pointing to.

Returns:

the tree cursor's current node

getCurrentFieldName

public String getCurrentFieldName()

Get the field name of the Node that the cursor is currently pointing to.

Returns:

the field name of the tree cursor's current node, null if the current node doesn't have a field

getCurrentTreeCursorNode

public TreeCursorNode getCurrentTreeCursorNode()

Get the TreeCursorNode representation of the Node that the cursor is currently pointing to.

Returns:

the tree cursor's current node

gotoFirstChild

public boolean gotoFirstChild()

Move the cursor to the first child of its current node.

Returns:

true if the cursor successfully moved, and false if there were no children

gotoFirstChild

public boolean gotoFirstChild(int offset)

Move the cursor to the first child of its current node that extends beyond the given byte offset.

Parameters:

offset - the starting byte of the child

Returns:

true if the cursor successfully moved, and false if no such child was found

Throws:

IllegalArgumentException - if offset is negative

ByteOffsetOutOfBoundsException - if offset is outside the current node's byte range

Since:

1.7.0

gotoFirstChild

public boolean gotoFirstChild(@NotNull
                              @NotNull Point point)

Move the cursor to the first child of its current node that extends beyond the given row-column offset.

Parameters:

point - the starting row-column position of the child

Returns:

true if the cursor successfully moved, and false if no such child was found

Throws:

NullPointerException - if point is null

PointOutOfBoundsException - if point is outside the current node's positional span

Since:

1.7.0

gotoNextSibling

public boolean gotoNextSibling()

Move the cursor to the next sibling of its current node.

Returns:

true if the cursor successfully moved, and false if there was no next sibling node

gotoParent

public boolean gotoParent()

Move the cursor to the parent of its current node.

Returns:

true if the cursor successfully moved, and false if there was no parent node (the cursor was already on the root node)

gotoNode

public boolean gotoNode(@NotNull
                        @NotNull Node node)

Move the cursor to an arbitrary node.

Parameters:

node - target node to move the cursor to.

Returns:

true if the cursor successfully moved, and false if it was already at the specified node

Throws:

NullPointerException - if node is null

IllegalArgumentException - if node is not present in the tree

Since:

1.9.0

preorderTraversal

public void preorderTraversal(@NotNull
                              @NotNull Consumer<Node> callback)

Iteratively traverse over the parse tree, applying a callback to the nodes before they are visited.

Parameters:

callback - The callback consumer which will execute upon visiting a node

Throws:

NullPointerException - if callback is null

clone

public TreeCursor clone()

Clone this cursor, creating a separate, independent instance.

Returns:

a clone of this instance

Since:

1.5.1

isNull

public final boolean isNull()

Checks whether the memory address associated with this external resource is nullptr.

Returns:

true if the memory address is 0, otherwise false

equals

public boolean equals(Object obj)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

close

public void close()

Delete the external resource, freeing all the memory that it used.

Specified by:

close in interface AutoCloseable