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636 lines
23 KiB
Rust
636 lines
23 KiB
Rust
use std::collections::HashMap;
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use tree_sitter::{Query, QueryCursor, QueryPredicateArg};
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use crate::{
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chars::{char_is_line_ending, char_is_whitespace},
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syntax::{LanguageConfiguration, RopeProvider, Syntax},
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tree_sitter::Node,
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Rope, RopeSlice,
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};
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/// Enum representing indentation style.
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///
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/// Only values 1-8 are valid for the `Spaces` variant.
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#[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
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pub enum IndentStyle {
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Tabs,
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Spaces(u8),
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}
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impl IndentStyle {
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/// Creates an `IndentStyle` from an indentation string.
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///
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/// For example, passing `" "` (four spaces) will create `IndentStyle::Spaces(4)`.
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#[allow(clippy::should_implement_trait)]
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#[inline]
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pub fn from_str(indent: &str) -> Self {
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// XXX: do we care about validating the input more than this? Probably not...?
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debug_assert!(!indent.is_empty() && indent.len() <= 8);
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if indent.starts_with(' ') {
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IndentStyle::Spaces(indent.len() as u8)
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} else {
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IndentStyle::Tabs
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}
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}
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#[inline]
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pub fn as_str(&self) -> &'static str {
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match *self {
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IndentStyle::Tabs => "\t",
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IndentStyle::Spaces(1) => " ",
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IndentStyle::Spaces(2) => " ",
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IndentStyle::Spaces(3) => " ",
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IndentStyle::Spaces(4) => " ",
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IndentStyle::Spaces(5) => " ",
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IndentStyle::Spaces(6) => " ",
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IndentStyle::Spaces(7) => " ",
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IndentStyle::Spaces(8) => " ",
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// Unsupported indentation style. This should never happen,
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// but just in case fall back to two spaces.
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IndentStyle::Spaces(n) => {
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debug_assert!(n > 0 && n <= 8); // Always triggers. `debug_panic!()` wanted.
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" "
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}
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}
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}
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}
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/// Attempts to detect the indentation style used in a document.
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///
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/// Returns the indentation style if the auto-detect confidence is
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/// reasonably high, otherwise returns `None`.
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pub fn auto_detect_indent_style(document_text: &Rope) -> Option<IndentStyle> {
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// Build a histogram of the indentation *increases* between
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// subsequent lines, ignoring lines that are all whitespace.
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//
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// Index 0 is for tabs, the rest are 1-8 spaces.
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let histogram: [usize; 9] = {
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let mut histogram = [0; 9];
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let mut prev_line_is_tabs = false;
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let mut prev_line_leading_count = 0usize;
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// Loop through the lines, checking for and recording indentation
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// increases as we go.
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'outer: for line in document_text.lines().take(1000) {
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let mut c_iter = line.chars();
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// Is first character a tab or space?
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let is_tabs = match c_iter.next() {
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Some('\t') => true,
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Some(' ') => false,
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// Ignore blank lines.
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Some(c) if char_is_line_ending(c) => continue,
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_ => {
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prev_line_is_tabs = false;
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prev_line_leading_count = 0;
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continue;
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}
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};
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// Count the line's total leading tab/space characters.
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let mut leading_count = 1;
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let mut count_is_done = false;
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for c in c_iter {
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match c {
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'\t' if is_tabs && !count_is_done => leading_count += 1,
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' ' if !is_tabs && !count_is_done => leading_count += 1,
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// We stop counting if we hit whitespace that doesn't
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// qualify as indent or doesn't match the leading
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// whitespace, but we don't exit the loop yet because
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// we still want to determine if the line is blank.
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c if char_is_whitespace(c) => count_is_done = true,
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// Ignore blank lines.
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c if char_is_line_ending(c) => continue 'outer,
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_ => break,
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}
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// Bound the worst-case execution time for weird text files.
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if leading_count > 256 {
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continue 'outer;
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}
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}
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// If there was an increase in indentation over the previous
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// line, update the histogram with that increase.
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if (prev_line_is_tabs == is_tabs || prev_line_leading_count == 0)
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&& prev_line_leading_count < leading_count
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{
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if is_tabs {
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histogram[0] += 1;
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} else {
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let amount = leading_count - prev_line_leading_count;
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if amount <= 8 {
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histogram[amount] += 1;
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}
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}
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}
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// Store this line's leading whitespace info for use with
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// the next line.
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prev_line_is_tabs = is_tabs;
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prev_line_leading_count = leading_count;
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}
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// Give more weight to tabs, because their presence is a very
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// strong indicator.
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histogram[0] *= 2;
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histogram
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};
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// Find the most frequent indent, its frequency, and the frequency of
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// the next-most frequent indent.
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let indent = histogram
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.iter()
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.enumerate()
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.max_by_key(|kv| kv.1)
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.unwrap()
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.0;
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let indent_freq = histogram[indent];
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let indent_freq_2 = *histogram
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.iter()
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.enumerate()
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.filter(|kv| kv.0 != indent)
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.map(|kv| kv.1)
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.max()
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.unwrap();
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// Return the the auto-detected result if we're confident enough in its
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// accuracy, based on some heuristics.
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if indent_freq >= 1 && (indent_freq_2 as f64 / indent_freq as f64) < 0.66 {
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Some(match indent {
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0 => IndentStyle::Tabs,
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_ => IndentStyle::Spaces(indent as u8),
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})
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} else {
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None
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}
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}
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/// To determine indentation of a newly inserted line, figure out the indentation at the last col
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/// of the previous line.
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pub fn indent_level_for_line(line: RopeSlice, tab_width: usize) -> usize {
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let mut len = 0;
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for ch in line.chars() {
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match ch {
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'\t' => len += tab_width,
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' ' => len += 1,
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_ => break,
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}
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}
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len / tab_width
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}
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/// Computes for node and all ancestors whether they are the first node on their line.
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/// The first entry in the return value represents the root node, the last one the node itself
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fn get_first_in_line(mut node: Node, byte_pos: usize, new_line: bool) -> Vec<bool> {
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let mut first_in_line = Vec::new();
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loop {
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if let Some(prev) = node.prev_sibling() {
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// If we insert a new line, the first node at/after the cursor is considered to be the first in its line
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let first = prev.end_position().row != node.start_position().row
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|| (new_line && node.start_byte() >= byte_pos && prev.start_byte() < byte_pos);
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first_in_line.push(Some(first));
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} else {
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// Nodes that have no previous siblings are first in their line if and only if their parent is
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// (which we don't know yet)
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first_in_line.push(None);
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}
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if let Some(parent) = node.parent() {
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node = parent;
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} else {
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break;
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}
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}
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let mut result = Vec::with_capacity(first_in_line.len());
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let mut parent_is_first = true; // The root node is by definition the first node in its line
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for first in first_in_line.into_iter().rev() {
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if let Some(first) = first {
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result.push(first);
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parent_is_first = first;
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} else {
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result.push(parent_is_first);
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}
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}
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result
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}
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/// The total indent for some line of code.
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/// This is usually constructed in one of 2 ways:
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/// - Successively add indent captures to get the (added) indent from a single line
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/// - Successively add the indent results for each line
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#[derive(Default)]
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struct Indentation {
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/// The total indent (the number of indent levels) is defined as max(0, indent-outdent).
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/// The string that this results in depends on the indent style (spaces or tabs, etc.)
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indent: usize,
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outdent: usize,
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}
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impl Indentation {
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/// Add some other [IndentResult] to this.
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/// The added indent should be the total added indent from one line
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fn add_line(&mut self, added: &Indentation) {
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if added.indent > 0 && added.outdent == 0 {
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self.indent += 1;
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} else if added.outdent > 0 && added.indent == 0 {
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self.outdent += 1;
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}
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}
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/// Add an indent capture to this indent.
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/// All the captures that are added in this way should be on the same line.
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fn add_capture(&mut self, added: IndentCaptureType) {
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match added {
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IndentCaptureType::Indent => {
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self.indent = 1;
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}
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IndentCaptureType::Outdent => {
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self.outdent = 1;
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}
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}
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}
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fn as_string(&self, indent_style: &IndentStyle) -> String {
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let indent_level = if self.indent >= self.outdent {
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self.indent - self.outdent
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} else {
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log::warn!("Encountered more outdent than indent nodes while calculating indentation: {} outdent, {} indent", self.outdent, self.indent);
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0
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};
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indent_style.as_str().repeat(indent_level)
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}
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}
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/// An indent definition which corresponds to a capture from the indent query
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struct IndentCapture {
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capture_type: IndentCaptureType,
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scope: IndentScope,
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}
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#[derive(Clone, Copy)]
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enum IndentCaptureType {
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Indent,
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Outdent,
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}
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impl IndentCaptureType {
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fn default_scope(&self) -> IndentScope {
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match self {
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IndentCaptureType::Indent => IndentScope::Tail,
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IndentCaptureType::Outdent => IndentScope::All,
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}
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}
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}
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/// This defines which part of a node an [IndentCapture] applies to.
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/// Each [IndentCaptureType] has a default scope, but the scope can be changed
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/// with `#set!` property declarations.
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#[derive(Clone, Copy)]
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enum IndentScope {
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/// The indent applies to the whole node
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All,
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/// The indent applies to everything except for the first line of the node
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Tail,
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}
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/// Execute the indent query.
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/// Returns for each node (identified by its id) a list of indent captures for that node.
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fn query_indents(
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query: &Query,
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syntax: &Syntax,
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cursor: &mut QueryCursor,
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text: RopeSlice,
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range: std::ops::Range<usize>,
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// Position of the (optional) newly inserted line break.
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// Given as (line, byte_pos)
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new_line_break: Option<(usize, usize)>,
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) -> HashMap<usize, Vec<IndentCapture>> {
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let mut indent_captures: HashMap<usize, Vec<IndentCapture>> = HashMap::new();
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cursor.set_byte_range(range);
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// Iterate over all captures from the query
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for m in cursor.matches(query, syntax.tree().root_node(), RopeProvider(text)) {
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// Skip matches where not all custom predicates are fulfilled
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if !query.general_predicates(m.pattern_index).iter().all(|pred| {
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match pred.operator.as_ref() {
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"not-kind-eq?" => match (pred.args.get(0), pred.args.get(1)) {
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(
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Some(QueryPredicateArg::Capture(capture_idx)),
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Some(QueryPredicateArg::String(kind)),
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) => {
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let node = m.nodes_for_capture_index(*capture_idx).next();
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match node {
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Some(node) => node.kind()!=kind.as_ref(),
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_ => true,
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}
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}
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_ => {
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panic!("Invalid indent query: Arguments to \"not-kind-eq?\" must be a capture and a string");
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}
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},
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"same-line?" | "not-same-line?" => {
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match (pred.args.get(0), pred.args.get(1)) {
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(
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Some(QueryPredicateArg::Capture(capt1)),
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Some(QueryPredicateArg::Capture(capt2))
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) => {
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let get_line_num = |node: Node| {
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let mut node_line = node.start_position().row;
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// Adjust for the new line that will be inserted
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if let Some((line, byte)) = new_line_break {
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if node_line==line && node.start_byte()>=byte {
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node_line += 1;
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}
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}
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node_line
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};
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let n1 = m.nodes_for_capture_index(*capt1).next();
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let n2 = m.nodes_for_capture_index(*capt2).next();
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match (n1, n2) {
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(Some(n1), Some(n2)) => {
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let same_line = get_line_num(n1)==get_line_num(n2);
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same_line==(pred.operator.as_ref()=="same-line?")
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}
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_ => true,
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}
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}
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_ => {
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panic!("Invalid indent query: Arguments to \"{}\" must be 2 captures", pred.operator);
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}
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}
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}
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_ => {
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panic!(
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"Invalid indent query: Unknown predicate (\"{}\")",
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pred.operator
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);
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}
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}
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}) {
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continue;
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}
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for capture in m.captures {
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let capture_type = query.capture_names()[capture.index as usize].as_str();
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let capture_type = match capture_type {
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"indent" => IndentCaptureType::Indent,
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"outdent" => IndentCaptureType::Outdent,
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_ => {
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// Ignore any unknown captures (these may be needed for predicates such as #match?)
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continue;
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}
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};
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let scope = capture_type.default_scope();
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let mut indent_capture = IndentCapture {
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capture_type,
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scope,
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};
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// Apply additional settings for this capture
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for property in query.property_settings(m.pattern_index) {
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match property.key.as_ref() {
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"scope" => {
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indent_capture.scope = match property.value.as_deref() {
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Some("all") => IndentScope::All,
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Some("tail") => IndentScope::Tail,
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Some(s) => {
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panic!("Invalid indent query: Unknown value for \"scope\" property (\"{}\")", s);
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}
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None => {
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panic!(
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"Invalid indent query: Missing value for \"scope\" property"
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);
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}
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}
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}
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_ => {
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panic!(
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"Invalid indent query: Unknown property \"{}\"",
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property.key
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);
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}
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}
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}
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indent_captures
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.entry(capture.node.id())
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// Most entries only need to contain a single IndentCapture
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.or_insert_with(|| Vec::with_capacity(1))
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.push(indent_capture);
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}
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}
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indent_captures
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}
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/// Use the syntax tree to determine the indentation for a given position.
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/// This can be used in 2 ways:
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///
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/// - To get the correct indentation for an existing line (new_line=false), not necessarily equal to the current indentation.
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/// - In this case, pos should be inside the first tree-sitter node on that line.
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/// In most cases, this can just be the first non-whitespace on that line.
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/// - To get the indentation for a new line (new_line=true). This behaves like the first usecase if the part of the current line
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/// after pos were moved to a new line.
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///
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/// The indentation is determined by traversing all the tree-sitter nodes containing the position.
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/// Each of these nodes produces some [AddedIndent] for:
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///
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/// - The line of the (beginning of the) node. This is defined by the scope `all` if this is the first node on its line.
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/// - The line after the node. This is defined by:
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/// - The scope `tail`.
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/// - The scope `all` if this node is not the first node on its line.
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/// Intuitively, `all` applies to everything contained in this node while `tail` applies to everything except for the first line of the node.
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/// The indents from different nodes for the same line are then combined.
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/// The [IndentResult] is simply the sum of the [AddedIndent] for all lines.
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///
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/// Specifying which line exactly an [AddedIndent] applies to is important because indents on the same line combine differently than indents on different lines:
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/// ```ignore
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/// some_function(|| {
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/// // Both the function parameters as well as the contained block should be indented.
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/// // Because they are on the same line, this only yields one indent level
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/// });
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/// ```
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///
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/// ```ignore
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/// some_function(
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/// parm1,
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/// || {
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/// // Here we get 2 indent levels because the 'parameters' and the 'block' node begin on different lines
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/// },
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/// );
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/// ```
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pub fn treesitter_indent_for_pos(
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query: &Query,
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syntax: &Syntax,
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indent_style: &IndentStyle,
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text: RopeSlice,
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line: usize,
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pos: usize,
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new_line: bool,
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) -> Option<String> {
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let byte_pos = text.char_to_byte(pos);
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let mut node = syntax
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.tree()
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.root_node()
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.descendant_for_byte_range(byte_pos, byte_pos)?;
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let mut first_in_line = get_first_in_line(node, byte_pos, new_line);
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let new_line_break = if new_line {
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Some((line, byte_pos))
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} else {
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None
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};
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let query_result = crate::syntax::PARSER.with(|ts_parser| {
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let mut ts_parser = ts_parser.borrow_mut();
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let mut cursor = ts_parser.cursors.pop().unwrap_or_else(QueryCursor::new);
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let query_result = query_indents(
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query,
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syntax,
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&mut cursor,
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text,
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byte_pos..byte_pos + 1,
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new_line_break,
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);
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ts_parser.cursors.push(cursor);
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query_result
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});
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let mut result = Indentation::default();
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// We always keep track of all the indent changes on one line, in order to only indent once
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// even if there are multiple "indent" nodes on the same line
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let mut indent_for_line = Indentation::default();
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let mut indent_for_line_below = Indentation::default();
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loop {
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// This can safely be unwrapped because `first_in_line` contains
|
|
// one entry for each ancestor of the node (which is what we iterate over)
|
|
let is_first = *first_in_line.last().unwrap();
|
|
// Apply all indent definitions for this node
|
|
if let Some(definitions) = query_result.get(&node.id()) {
|
|
for definition in definitions {
|
|
match definition.scope {
|
|
IndentScope::All => {
|
|
if is_first {
|
|
indent_for_line.add_capture(definition.capture_type);
|
|
} else {
|
|
indent_for_line_below.add_capture(definition.capture_type);
|
|
}
|
|
}
|
|
IndentScope::Tail => {
|
|
indent_for_line_below.add_capture(definition.capture_type);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
if let Some(parent) = node.parent() {
|
|
let mut node_line = node.start_position().row;
|
|
let mut parent_line = parent.start_position().row;
|
|
if node_line == line && new_line {
|
|
// Also consider the line that will be inserted
|
|
if node.start_byte() >= byte_pos {
|
|
node_line += 1;
|
|
}
|
|
if parent.start_byte() >= byte_pos {
|
|
parent_line += 1;
|
|
}
|
|
};
|
|
if node_line != parent_line {
|
|
if node_line < line + (new_line as usize) {
|
|
// Don't add indent for the line below the line of the query
|
|
result.add_line(&indent_for_line_below);
|
|
}
|
|
if node_line == parent_line + 1 {
|
|
indent_for_line_below = indent_for_line;
|
|
} else {
|
|
result.add_line(&indent_for_line);
|
|
indent_for_line_below = Indentation::default();
|
|
}
|
|
indent_for_line = Indentation::default();
|
|
}
|
|
|
|
node = parent;
|
|
first_in_line.pop();
|
|
} else {
|
|
result.add_line(&indent_for_line_below);
|
|
result.add_line(&indent_for_line);
|
|
break;
|
|
}
|
|
}
|
|
Some(result.as_string(indent_style))
|
|
}
|
|
|
|
/// Returns the indentation for a new line.
|
|
/// This is done either using treesitter, or if that's not available by copying the indentation from the current line
|
|
#[allow(clippy::too_many_arguments)]
|
|
pub fn indent_for_newline(
|
|
language_config: Option<&LanguageConfiguration>,
|
|
syntax: Option<&Syntax>,
|
|
indent_style: &IndentStyle,
|
|
tab_width: usize,
|
|
text: RopeSlice,
|
|
line_before: usize,
|
|
line_before_end_pos: usize,
|
|
current_line: usize,
|
|
) -> String {
|
|
if let (Some(query), Some(syntax)) = (
|
|
language_config.and_then(|config| config.indent_query()),
|
|
syntax,
|
|
) {
|
|
if let Some(indent) = treesitter_indent_for_pos(
|
|
query,
|
|
syntax,
|
|
indent_style,
|
|
text,
|
|
line_before,
|
|
line_before_end_pos,
|
|
true,
|
|
) {
|
|
return indent;
|
|
};
|
|
}
|
|
let indent_level = indent_level_for_line(text.line(current_line), tab_width);
|
|
indent_style.as_str().repeat(indent_level)
|
|
}
|
|
|
|
pub fn get_scopes(syntax: Option<&Syntax>, text: RopeSlice, pos: usize) -> Vec<&'static str> {
|
|
let mut scopes = Vec::new();
|
|
if let Some(syntax) = syntax {
|
|
let pos = text.char_to_byte(pos);
|
|
let mut node = match syntax
|
|
.tree()
|
|
.root_node()
|
|
.descendant_for_byte_range(pos, pos)
|
|
{
|
|
Some(node) => node,
|
|
None => return scopes,
|
|
};
|
|
|
|
scopes.push(node.kind());
|
|
|
|
while let Some(parent) = node.parent() {
|
|
scopes.push(parent.kind());
|
|
node = parent;
|
|
}
|
|
}
|
|
|
|
scopes.reverse();
|
|
scopes
|
|
}
|
|
|
|
#[cfg(test)]
|
|
mod test {
|
|
use super::*;
|
|
use crate::Rope;
|
|
|
|
#[test]
|
|
fn test_indent_level() {
|
|
let tab_width = 4;
|
|
let line = Rope::from(" fn new"); // 8 spaces
|
|
assert_eq!(indent_level_for_line(line.slice(..), tab_width), 2);
|
|
let line = Rope::from("\t\t\tfn new"); // 3 tabs
|
|
assert_eq!(indent_level_for_line(line.slice(..), tab_width), 3);
|
|
// mixed indentation
|
|
let line = Rope::from("\t \tfn new"); // 1 tab, 4 spaces, tab
|
|
assert_eq!(indent_level_for_line(line.slice(..), tab_width), 3);
|
|
}
|
|
}
|