tree_root_node_with_offset {treesitter}

Retrieve an offset root node

Description

tree_root_node_with_offset() is similar to tree_root_node(), but the returned root node's position has been shifted by the given number of bytes, rows, and columns.

This function allows you to parse a subset of a document with parser_parse() as if it were a self-contained document, but then later access the syntax tree in the coordinate space of the larger document.

Note that the underlying text within x is not what you are offsetting into. Instead, you should assume that the text you provided to parser_parse() already contained the entire subset of the document you care about, and the offset you are providing is how far into the document the beginning of text is.

Usage

tree_root_node_with_offset(x, byte, point)

Arguments

x

⁠[tree_sitter_tree]⁠

A tree.

byte, point

⁠[double(1), tree_sitter_point]⁠

A byte and point offset combination.

Value

An offset root node.

Examples

language <- treesitter.r::language()
parser <- parser(language)

text <- "fn <- function() { 1 + 1 }"
tree <- parser_parse(parser, text)

# If `text` was the whole document, you can just use `tree_root_node()`
node <- tree_root_node(tree)

# If `text` represents a subset of the document, use
# `tree_root_node_with_offset()` to be able to get positions in the
# coordinate space of the original document.
byte <- 5
point <- point(5, 0)
node_offset <- tree_root_node_with_offset(tree, byte, point)

# The position of `fn` if you treat `text` as the whole document
node |>
  node_child(1) |>
  node_child(1)

# The position of `fn` if you treat `text` as a subset of a larger document
node_offset |>
  node_child(1) |>
  node_child(1)