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helix-plus/helix-core/src/indent.rs

313 lines
8.3 KiB
Rust

use crate::{
find_first_non_whitespace_char,
syntax::Syntax,
tree_sitter::{Node, Tree},
Rope, RopeSlice, State,
};
/// To determine indentation of a newly inserted line, figure out the indentation at the last col
/// of the previous line.
pub const TAB_WIDTH: usize = 4;
fn indent_level_for_line(line: RopeSlice) -> usize {
let mut len = 0;
for ch in line.chars() {
match ch {
'\t' => len += TAB_WIDTH,
' ' => len += 1,
_ => break,
}
}
len / TAB_WIDTH
}
/// Find the highest syntax node at position.
/// This is to identify the column where this node (e.g., an HTML closing tag) ends.
fn get_highest_syntax_node_at_bytepos(syntax: &Syntax, pos: usize) -> Option<Node> {
let tree = syntax.root_layer.tree.as_ref().unwrap();
// named_descendant
let mut node = match tree.root_node().descendant_for_byte_range(pos, pos) {
Some(node) => node,
None => return None,
};
while let Some(parent) = node.parent() {
if parent.start_byte() == node.start_byte() {
node = parent
} else {
break;
}
}
Some(node)
}
fn calculate_indentation(node: Option<Node>, newline: bool) -> usize {
let mut increment: i32 = 0;
// Hardcoded for rust for now
let indent_scopes = &[
// indent except first or block?
"while_expression",
"for_expression",
"loop_expression",
"if_expression",
"if_let_expression",
// "match_expression",
// "match_arm",
];
// this is for multiline things, such as:
// self.method()
// .chain()
// .chain()
// where the first line isn't indented
let indent_except_first_scopes = &[
"block",
"match_block",
"arguments",
"declaration_list",
"field_declaration_list",
"enum_variant_list",
// "function_item",
// "closure_expression",
"binary_expression",
"field_expression",
//
"where_clause",
//
"use_list",
];
let outdent = &["where", "}", "]", ")"];
let mut node = match node {
Some(node) => node,
None => return 0,
};
let mut prev_start = node.start_position().row;
// if we're calculating indentation for a brand new line then the current node will become the
// parent node. We need to take it's indentation level into account too.
let node_kind = node.kind();
if newline
&& (indent_scopes.contains(&node_kind) || indent_except_first_scopes.contains(&node_kind))
{
increment += 1;
}
while let Some(parent) = node.parent() {
let not_first_sibling = node.prev_sibling().is_some();
let not_last_sibling = node.next_sibling().is_some();
let not_first_or_last_sibling = not_first_sibling && not_last_sibling;
let parent_kind = parent.kind();
let start = parent.start_position().row;
// println!(
// "name: {}\tparent: {}\trange:\t{} {}\tfirst={:?}\tlast={:?} start={} prev={}",
// node.kind(),
// parent.kind(),
// node.range().start_point,
// node.range().end_point,
// node.prev_sibling().is_none(),
// node.next_sibling().is_none(),
// node.start_position(),
// prev_start,
// );
// detect deeply nested indents in the same line
let starts_same_line = start == prev_start;
if outdent.contains(&node.kind()) {
// we outdent by skipping the rules for the current level and jumping up
// println!("skipping..");
// node = parent;
increment -= 1;
// continue;
}
// TODO: problem seems to be, ({ is two scopes that merge into one.
// so when seeing } we're supposed to jump all the way out of both scopes, but we only do
// so for one.
// .map(|a| {
// let len = 1;
// })
if (indent_scopes.contains(&parent_kind) // && not_first_or_last_sibling
|| indent_except_first_scopes.contains(&parent_kind))
&& !starts_same_line
{
// println!("is_scope {}", parent_kind);
prev_start = start;
increment += 1
}
// TODO: detect deeply nested indents in same line:
// std::panic::set_hook(Box::new(move |info| {
// hook(info); <-- indent here is 1
// }));
// if last_scope && increment > 0 && ...{ ignore }
node = parent;
}
assert!(increment >= 0);
increment as usize
}
fn suggested_indent_for_line(syntax: Option<&Syntax>, state: &State, line_num: usize) -> usize {
4 years ago
let line = state.doc.line(line_num);
let current = indent_level_for_line(line);
4 years ago
if let Some(start) = find_first_non_whitespace_char(state.doc.slice(..), line_num) {
return suggested_indent_for_pos(syntax, state, start, false);
};
// if the line is blank, indent should be zero
0
}
// TODO: two usecases: if we are triggering this for a new, blank line:
// - it should return 0 when mass indenting stuff
// - it should look up the wrapper node and count it too when we press o/O
pub fn suggested_indent_for_pos(
syntax: Option<&Syntax>,
state: &State,
pos: usize,
new_line: bool,
) -> usize {
if let Some(syntax) = syntax {
let byte_start = state.doc.char_to_byte(pos);
let node = get_highest_syntax_node_at_bytepos(syntax, byte_start);
// TODO: special case for comments
// TODO: if preserve_leading_whitespace
calculate_indentation(node, new_line)
} else {
4 years ago
// TODO: heuristics for non-tree sitter grammars
0
}
}
#[cfg(test)]
mod test {
use super::*;
#[test]
fn test_indent_level() {
let line = Rope::from(" fn new"); // 8 spaces
assert_eq!(indent_level_for_line(line.slice(..)), 2);
let line = Rope::from("\t\t\tfn new"); // 3 tabs
assert_eq!(indent_level_for_line(line.slice(..)), 3);
// mixed indentation
let line = Rope::from("\t \tfn new"); // 1 tab, 4 spaces, tab
assert_eq!(indent_level_for_line(line.slice(..)), 3);
}
#[test]
fn test_suggested_indent_for_line() {
let doc = Rope::from(
"
use std::{
io::{self, stdout, Stdout, Write},
path::PathBuf,
sync::Arc,
time::Duration,
}
mod test {
fn hello_world() {
1 + 1;
let does_indentation_work = 1;
let test_function = function_with_param(this_param,
that_param
);
let test_function = function_with_param(
this_param,
that_param
);
let test_function = function_with_proper_indent(param1,
param2,
);
let selection = Selection::new(
changes
.clone()
.map(|(start, end, text): (usize, usize, Option<Tendril>)| {
let len = text.map(|text| text.len()).unwrap() - 1; // minus newline
let pos = start + len;
Range::new(pos, pos)
})
.collect(),
0,
);
return;
}
}
impl<A, D> MyTrait<A, D> for YourType
where
A: TraitB + TraitC,
D: TraitE + TraitF,
{
}
#[test]
//
match test {
Some(a) => 1,
None => {
unimplemented!()
}
}
std::panic::set_hook(Box::new(move |info| {
hook(info);
}));
{ { {
1
}}}
pub fn change<I>(state: &State, changes: I) -> Self
where
I: IntoIterator<Item = Change> + ExactSizeIterator,
{
true
}
",
);
let state = State::new(doc);
// TODO: set_language
let language_config = crate::syntax::LOADER
.language_config_for_scope("source.rust")
.unwrap();
let highlight_config = language_config.highlight_config(&[]).unwrap().unwrap();
let syntax = Syntax::new(&state.doc, highlight_config.clone());
let text = state.doc.slice(..);
for i in 0..state.doc.len_lines() {
let line = text.line(i);
let indent = indent_level_for_line(line);
assert_eq!(
suggested_indent_for_line(Some(&syntax), &state, i),
indent,
"line {}: {}",
i,
line
);
}
}
}