use syntax::{ ast::{self, AstNode}, SourceFile, SyntaxKind, TextSize, T, }; // Feature: Matching Brace // // If the cursor is on any brace (`<>(){}[]||`) which is a part of a brace-pair, // moves cursor to the matching brace. It uses the actual parser to determine // braces, so it won't confuse generics with comparisons. // // |=== // | Editor | Action Name // // | VS Code | **Rust Analyzer: Find matching brace** // |=== // // image::https://user-images.githubusercontent.com/48062697/113065573-04298180-91b1-11eb-8dec-d4e2a202f304.gif[] pub(crate) fn matching_brace(file: &SourceFile, offset: TextSize) -> Option { const BRACES: &[SyntaxKind] = &[T!['{'], T!['}'], T!['['], T![']'], T!['('], T![')'], T![<], T![>], T![|], T![|]]; let (brace_token, brace_idx) = file .syntax() .token_at_offset(offset) .filter_map(|node| { let idx = BRACES.iter().position(|&brace| brace == node.kind())?; Some((node, idx)) }) .next()?; let parent = brace_token.parent()?; if brace_token.kind() == T![|] && !ast::ParamList::can_cast(parent.kind()) { cov_mark::hit!(pipes_not_braces); return None; } let matching_kind = BRACES[brace_idx ^ 1]; let matching_node = parent .children_with_tokens() .filter_map(|it| it.into_token()) .find(|node| node.kind() == matching_kind && node != &brace_token)?; Some(matching_node.text_range().start()) } #[cfg(test)] mod tests { use test_utils::{add_cursor, assert_eq_text, extract_offset}; use super::*; #[test] fn test_matching_brace() { fn do_check(before: &str, after: &str) { let (pos, before) = extract_offset(before); let parse = SourceFile::parse(&before); let new_pos = match matching_brace(&parse.tree(), pos) { None => pos, Some(pos) => pos, }; let actual = add_cursor(&before, new_pos); assert_eq_text!(after, &actual); } do_check("struct Foo { a: i32, }$0", "struct Foo $0{ a: i32, }"); do_check("fn main() { |x: i32|$0 x * 2;}", "fn main() { $0|x: i32| x * 2;}"); do_check("fn main() { $0|x: i32| x * 2;}", "fn main() { |x: i32$0| x * 2;}"); { cov_mark::check!(pipes_not_braces); do_check( "fn main() { match 92 { 1 | 2 |$0 3 => 92 } }", "fn main() { match 92 { 1 | 2 |$0 3 => 92 } }", ); } } }