treesitter (version 0.3.0)

TreeCursor: Tree cursors

Description

TreeCursor is an R6 class that allows you to walk a tree in a more efficient way than calling node_*() functions like node_child() repeatedly.

You can also more elegantly create a cursor with node_walk() and tree_walk().

Value

R6 object representing the tree cursor.

Methods

Public methods

• TreeCursor$new()

• TreeCursor$reset()

• TreeCursor$node()

• TreeCursor$field_name()

• TreeCursor$field_id()

• TreeCursor$descendant_index()

• TreeCursor$goto_parent()

• TreeCursor$goto_next_sibling()

• TreeCursor$goto_previous_sibling()

• TreeCursor$goto_first_child()

• TreeCursor$goto_last_child()

• TreeCursor$depth()

• TreeCursor$goto_first_child_for_byte()

• TreeCursor$goto_first_child_for_point()

---

Method new()

Create a new tree cursor.

Usage

TreeCursor$new(node)

Arguments

node

[tree_sitter_node]

The node to start walking from.

---

Method reset()

Reset the tree cursor to a new root node.

Usage

TreeCursor$reset(node)

Arguments

node

[tree_sitter_node]

The node to start walking from.

---

Method node()

Get the current node that the cursor points to.

Usage

TreeCursor$node()

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Method field_name()

Get the field name of the current node.

Usage

TreeCursor$field_name()

---

Method field_id()

Get the field id of the current node.

Usage

TreeCursor$field_id()

---

Method descendant_index()

Get the descendent index of the current node.

Usage

TreeCursor$descendant_index()

---

Method goto_parent()

Go to the current node's parent.

Returns TRUE if a parent was found, and FALSE if not.

Usage

TreeCursor$goto_parent()

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Method goto_next_sibling()

Go to the current node's next sibling.

Returns TRUE if a sibling was found, and FALSE if not.

Usage

TreeCursor$goto_next_sibling()

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Method goto_previous_sibling()

Go to the current node's previous sibling.

Returns TRUE if a sibling was found, and FALSE if not.

Usage

TreeCursor$goto_previous_sibling()

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Method goto_first_child()

Go to the current node's first child.

Returns TRUE if a child was found, and FALSE if not.

Usage

TreeCursor$goto_first_child()

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Method goto_last_child()

Go to the current node's last child.

Returns TRUE if a child was found, and FALSE if not.

Usage

TreeCursor$goto_last_child()

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Method depth()

Get the depth of the current node.

Usage

TreeCursor$depth()

---

Method goto_first_child_for_byte()

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

Returns TRUE if a child was found, and FALSE if not.

Usage

TreeCursor$goto_first_child_for_byte(byte)

Arguments

byte

[double(1)]

The byte to move the cursor past.

---

Method goto_first_child_for_point()

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

Returns TRUE if a child was found, and FALSE if not.

Usage

TreeCursor$goto_first_child_for_point(point)

Arguments

point

[tree_sitter_point]

The point to move the cursor past.

Examples

if (FALSE) { # rlang::is_installed("treesitter.r")
language <- treesitter.r::language()
parser <- parser(language)

text <- "fn <- function(a, b) { a + b }"

tree <- parser_parse(parser, text)
node <- tree_root_node(tree)

cursor <- TreeCursor$new(node)

cursor$node()
cursor$goto_first_child()
cursor$goto_first_child()
cursor$node()
cursor$goto_next_sibling()
cursor$node()
}