use crate::{search, Selection}; use ropey::RopeSlice; pub const PAIRS: &[(char, char)] = &[ ('(', ')'), ('[', ']'), ('{', '}'), ('<', '>'), ('«', '»'), ('「', '」'), ('(', ')'), ]; /// Given any char in [PAIRS], return the open and closing chars. If not found in /// [PAIRS] return (ch, ch). /// /// ``` /// use helix_core::surround::get_pair; /// /// assert_eq!(get_pair('['), ('[', ']')); /// assert_eq!(get_pair('}'), ('{', '}')); /// assert_eq!(get_pair('"'), ('"', '"')); /// ``` pub fn get_pair(ch: char) -> (char, char) { PAIRS .iter() .find(|(open, close)| *open == ch || *close == ch) .copied() .unwrap_or((ch, ch)) } /// Find the position of surround pairs of `ch` which can be either a closing /// or opening pair. `n` will skip n - 1 pairs (eg. n=2 will discard (only) /// the first pair found and keep looking) pub fn find_nth_pairs_pos( text: RopeSlice, ch: char, pos: usize, n: usize, ) -> Option<(usize, usize)> { let (open, close) = get_pair(ch); if text.len_chars() < 2 || pos >= text.len_chars() { return None; } if open == close { if Some(open) == text.get_char(pos) { // Special case: cursor is directly on a matching char. match pos { 0 => Some((pos, search::find_nth_next(text, close, pos + 1, n)?)), _ if (pos + 1) == text.len_chars() => { Some((search::find_nth_prev(text, open, pos, n)?, pos)) } // We return no match because there's no way to know which // side of the char we should be searching on. _ => None, } } else { Some(( search::find_nth_prev(text, open, pos, n)?, search::find_nth_next(text, close, pos, n)?, )) } } else { Some(( find_nth_open_pair(text, open, close, pos, n)?, find_nth_close_pair(text, open, close, pos, n)?, )) } } fn find_nth_open_pair( text: RopeSlice, open: char, close: char, mut pos: usize, n: usize, ) -> Option { let mut chars = text.chars_at(pos + 1); // Adjusts pos for the first iteration, and handles the case of the // cursor being *on* the close character which will get falsely stepped over // if not skipped here if chars.prev()? == open { return Some(pos); } for _ in 0..n { let mut step_over: usize = 0; loop { let c = chars.prev()?; pos = pos.saturating_sub(1); // ignore other surround pairs that are enclosed *within* our search scope if c == close { step_over += 1; } else if c == open { if step_over == 0 { break; } step_over = step_over.saturating_sub(1); } } } Some(pos) } fn find_nth_close_pair( text: RopeSlice, open: char, close: char, mut pos: usize, n: usize, ) -> Option { if pos >= text.len_chars() { return None; } let mut chars = text.chars_at(pos); if chars.next()? == close { return Some(pos); } for _ in 0..n { let mut step_over: usize = 0; loop { let c = chars.next()?; pos += 1; if c == open { step_over += 1; } else if c == close { if step_over == 0 { break; } step_over = step_over.saturating_sub(1); } } } Some(pos) } /// Find position of surround characters around every cursor. Returns None /// if any positions overlap. Note that the positions are in a flat Vec. /// Use get_surround_pos().chunks(2) to get matching pairs of surround positions. /// `ch` can be either closing or opening pair. pub fn get_surround_pos( text: RopeSlice, selection: &Selection, ch: char, skip: usize, ) -> Option> { let mut change_pos = Vec::new(); for range in selection { let (open_pos, close_pos) = find_nth_pairs_pos(text, ch, range.head, skip)?; if change_pos.contains(&open_pos) || change_pos.contains(&close_pos) { return None; } change_pos.extend_from_slice(&[open_pos, close_pos]); } Some(change_pos) } #[cfg(test)] mod test { use super::*; use crate::Range; use ropey::Rope; use smallvec::SmallVec; #[test] fn test_find_nth_pairs_pos() { let doc = Rope::from("some (text) here"); let slice = doc.slice(..); // cursor on [t]ext assert_eq!(find_nth_pairs_pos(slice, '(', 6, 1), Some((5, 10))); assert_eq!(find_nth_pairs_pos(slice, ')', 6, 1), Some((5, 10))); // cursor on so[m]e assert_eq!(find_nth_pairs_pos(slice, '(', 2, 1), None); // cursor on bracket itself assert_eq!(find_nth_pairs_pos(slice, '(', 5, 1), Some((5, 10))); assert_eq!(find_nth_pairs_pos(slice, '(', 10, 1), Some((5, 10))); } #[test] fn test_find_nth_pairs_pos_skip() { let doc = Rope::from("(so (many (good) text) here)"); let slice = doc.slice(..); // cursor on go[o]d assert_eq!(find_nth_pairs_pos(slice, '(', 13, 1), Some((10, 15))); assert_eq!(find_nth_pairs_pos(slice, '(', 13, 2), Some((4, 21))); assert_eq!(find_nth_pairs_pos(slice, '(', 13, 3), Some((0, 27))); } #[test] fn test_find_nth_pairs_pos_same() { let doc = Rope::from("'so 'many 'good' text' here'"); let slice = doc.slice(..); // cursor on go[o]d assert_eq!(find_nth_pairs_pos(slice, '\'', 13, 1), Some((10, 15))); assert_eq!(find_nth_pairs_pos(slice, '\'', 13, 2), Some((4, 21))); assert_eq!(find_nth_pairs_pos(slice, '\'', 13, 3), Some((0, 27))); // cursor on the quotes assert_eq!(find_nth_pairs_pos(slice, '\'', 10, 1), None); // this is the best we can do since opening and closing pairs are same assert_eq!(find_nth_pairs_pos(slice, '\'', 0, 1), Some((0, 4))); assert_eq!(find_nth_pairs_pos(slice, '\'', 27, 1), Some((21, 27))); } #[test] fn test_find_nth_pairs_pos_step() { let doc = Rope::from("((so)((many) good (text))(here))"); let slice = doc.slice(..); // cursor on go[o]d assert_eq!(find_nth_pairs_pos(slice, '(', 15, 1), Some((5, 24))); assert_eq!(find_nth_pairs_pos(slice, '(', 15, 2), Some((0, 31))); } #[test] fn test_find_nth_pairs_pos_mixed() { let doc = Rope::from("(so [many {good} text] here)"); let slice = doc.slice(..); // cursor on go[o]d assert_eq!(find_nth_pairs_pos(slice, '{', 13, 1), Some((10, 15))); assert_eq!(find_nth_pairs_pos(slice, '[', 13, 1), Some((4, 21))); assert_eq!(find_nth_pairs_pos(slice, '(', 13, 1), Some((0, 27))); } #[test] fn test_get_surround_pos() { let doc = Rope::from("(some) (chars)\n(newline)"); let slice = doc.slice(..); let selection = Selection::new( SmallVec::from_slice(&[Range::point(2), Range::point(9), Range::point(20)]), 0, ); // cursor on s[o]me, c[h]ars, newl[i]ne assert_eq!( get_surround_pos(slice, &selection, '(', 1) .unwrap() .as_slice(), &[0, 5, 7, 13, 15, 23] ); } #[test] fn test_get_surround_pos_bail() { let doc = Rope::from("[some]\n(chars)xx\n(newline)"); let slice = doc.slice(..); let selection = Selection::new(SmallVec::from_slice(&[Range::point(2), Range::point(9)]), 0); // cursor on s[o]me, c[h]ars assert_eq!( get_surround_pos(slice, &selection, '(', 1), None // different surround chars ); let selection = Selection::new( SmallVec::from_slice(&[Range::point(14), Range::point(24)]), 0, ); // cursor on [x]x, newli[n]e assert_eq!( get_surround_pos(slice, &selection, '(', 1), None // overlapping surround chars ); } }