143 lines
5.1 KiB
Rust
143 lines
5.1 KiB
Rust
//! This module contains the functionality toggle comments on lines over the selection
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//! using the comment character defined in the user's `languages.toml`
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use crate::{
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find_first_non_whitespace_char, Change, Rope, RopeSlice, Selection, Tendril, Transaction,
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};
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use std::borrow::Cow;
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/// Given text, a comment token, and a set of line indices, returns the following:
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/// - Whether the given lines should be considered commented
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/// - If any of the lines are uncommented, all lines are considered as such.
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/// - The lines to change for toggling comments
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/// - This is all provided lines excluding blanks lines.
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/// - The column of the comment tokens
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/// - Column of existing tokens, if the lines are commented; column to place tokens at otherwise.
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/// - The margin to the right of the comment tokens
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/// - Defaults to `1`. If any existing comment token is not followed by a space, changes to `0`.
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fn find_line_comment(
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token: &str,
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text: RopeSlice,
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lines: impl IntoIterator<Item = usize>,
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) -> (bool, Vec<usize>, usize, usize) {
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let mut commented = true;
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let mut to_change = Vec::new();
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let mut min = usize::MAX; // minimum col for find_first_non_whitespace_char
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let mut margin = 1;
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let token_len = token.chars().count();
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for line in lines {
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let line_slice = text.line(line);
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if let Some(pos) = find_first_non_whitespace_char(line_slice) {
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let len = line_slice.len_chars();
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if pos < min {
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min = pos;
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}
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// line can be shorter than pos + token len
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let fragment = Cow::from(line_slice.slice(pos..std::cmp::min(pos + token.len(), len)));
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if fragment != token {
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// as soon as one of the non-blank lines doesn't have a comment, the whole block is
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// considered uncommented.
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commented = false;
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}
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// determine margin of 0 or 1 for uncommenting; if any comment token is not followed by a space,
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// a margin of 0 is used for all lines.
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if matches!(line_slice.get_char(pos + token_len), Some(c) if c != ' ') {
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margin = 0;
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}
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// blank lines don't get pushed.
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to_change.push(line);
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}
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}
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(commented, to_change, min, margin)
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}
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#[must_use]
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pub fn toggle_line_comments(doc: &Rope, selection: &Selection, token: Option<&str>) -> Transaction {
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let text = doc.slice(..);
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let token = token.unwrap_or("//");
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let comment = Tendril::from(format!("{} ", token));
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let mut lines: Vec<usize> = Vec::with_capacity(selection.len());
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let mut min_next_line = 0;
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for selection in selection {
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let (start, end) = selection.line_range(text);
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let start = start.max(min_next_line).min(text.len_lines());
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let end = (end + 1).min(text.len_lines());
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lines.extend(start..end);
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min_next_line = end;
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}
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let (commented, to_change, min, margin) = find_line_comment(token, text, lines);
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let mut changes: Vec<Change> = Vec::with_capacity(to_change.len());
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for line in to_change {
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let pos = text.line_to_char(line) + min;
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if !commented {
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// comment line
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changes.push((pos, pos, Some(comment.clone())));
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} else {
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// uncomment line
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changes.push((pos, pos + token.len() + margin, None));
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}
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}
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Transaction::change(doc, changes.into_iter())
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}
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#[cfg(test)]
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mod test {
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use super::*;
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#[test]
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fn test_find_line_comment() {
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use crate::State;
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// four lines, two space indented, except for line 1 which is blank.
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let doc = Rope::from(" 1\n\n 2\n 3");
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let mut state = State::new(doc);
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// select whole document
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state.selection = Selection::single(0, state.doc.len_chars() - 1);
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let text = state.doc.slice(..);
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let res = find_line_comment("//", text, 0..3);
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// (commented = true, to_change = [line 0, line 2], min = col 2, margin = 1)
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assert_eq!(res, (false, vec![0, 2], 2, 1));
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// comment
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let transaction = toggle_line_comments(&state.doc, &state.selection, None);
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transaction.apply(&mut state.doc);
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state.selection = state.selection.map(transaction.changes());
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assert_eq!(state.doc, " // 1\n\n // 2\n // 3");
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// uncomment
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let transaction = toggle_line_comments(&state.doc, &state.selection, None);
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transaction.apply(&mut state.doc);
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state.selection = state.selection.map(transaction.changes());
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assert_eq!(state.doc, " 1\n\n 2\n 3");
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// 0 margin comments
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state.doc = Rope::from(" //1\n\n //2\n //3");
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// reset the selection.
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state.selection = Selection::single(0, state.doc.len_chars() - 1);
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let transaction = toggle_line_comments(&state.doc, &state.selection, None);
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transaction.apply(&mut state.doc);
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state.selection = state.selection.map(transaction.changes());
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assert_eq!(state.doc, " 1\n\n 2\n 3");
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// TODO: account for uncommenting with uneven comment indentation
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}
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}
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