1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
|
use crate::graphemes::{nth_next_grapheme_boundary, nth_prev_grapheme_boundary, RopeGraphemes};
use crate::{coords_at_pos, pos_at_coords, ChangeSet, Position, Range, Rope, RopeSlice, Selection};
#[derive(Copy, Clone, PartialEq, Eq)]
pub enum Direction {
Forward,
Backward,
}
pub fn move_horizontally(
text: RopeSlice,
range: Range,
dir: Direction,
count: usize,
extend: bool,
) -> Range {
let pos = range.head;
let line = text.char_to_line(pos);
// TODO: we can optimize clamping by passing in RopeSlice limited to current line. that way
// we stop calculating past start/end of line.
let pos = match dir {
Direction::Backward => {
let start = text.line_to_char(line);
nth_prev_grapheme_boundary(text, pos, count).max(start)
}
Direction::Forward => {
// Line end is pos at the start of next line - 1
// subtract another 1 because the line ends with \n
let end = text.line_to_char(line + 1).saturating_sub(2);
nth_next_grapheme_boundary(text, pos, count).min(end)
}
};
Range::new(if extend { range.anchor } else { pos }, pos)
}
pub fn move_vertically(
text: RopeSlice,
range: Range,
dir: Direction,
count: usize,
extend: bool,
) -> Range {
let Position { row, col } = coords_at_pos(text, range.head);
let horiz = range.horiz.unwrap_or(col as u32);
let new_line = match dir {
Direction::Backward => row.saturating_sub(count),
Direction::Forward => std::cmp::min(row.saturating_add(count), text.len_lines() - 1),
};
// convert to 0-indexed, subtract another 1 because len_chars() counts \n
let new_line_len = text.line(new_line).len_chars().saturating_sub(2);
let new_col = std::cmp::min(horiz as usize, new_line_len);
let pos = pos_at_coords(text, Position::new(new_line, new_col));
let mut range = Range::new(if extend { range.anchor } else { pos }, pos);
range.horiz = Some(horiz);
range
}
pub fn move_next_word_start(slice: RopeSlice, mut begin: usize, count: usize) -> Option<Range> {
let mut end = begin;
for _ in 0..count {
if begin + 1 == slice.len_chars() {
return None;
}
let mut ch = slice.char(begin);
let next = slice.char(begin + 1);
// if we're at the end of a word, or on whitespce right before new one
if categorize(ch) != categorize(next) {
begin += 1;
}
// return if not skip while?
skip_over_next(slice, &mut begin, |ch| ch == '\n');
ch = slice.char(begin);
end = begin + 1;
if is_word(ch) {
skip_over_next(slice, &mut end, is_word);
} else if ch.is_ascii_punctuation() {
skip_over_next(slice, &mut end, |ch| ch.is_ascii_punctuation());
}
skip_over_next(slice, &mut end, is_horiz_blank);
}
Some(Range::new(begin, end - 1))
}
pub fn move_prev_word_start(slice: RopeSlice, mut begin: usize, count: usize) -> Option<Range> {
let mut with_end = false;
let mut end = begin;
for _ in 0..count {
if begin == 0 {
return None;
}
let ch = slice.char(begin);
let prev = slice.char(begin - 1);
if categorize(ch) != categorize(prev) {
begin -= 1;
}
// return if not skip while?
skip_over_prev(slice, &mut begin, |ch| ch == '\n');
end = begin;
with_end = skip_over_prev(slice, &mut end, is_horiz_blank);
// refetch
let ch = slice.char(end);
if is_word(ch) {
with_end = skip_over_prev(slice, &mut end, is_word);
} else if ch.is_ascii_punctuation() {
with_end = skip_over_prev(slice, &mut end, |ch| ch.is_ascii_punctuation());
}
}
Some(Range::new(begin, if with_end { end } else { end + 1 }))
}
pub fn move_next_word_end(slice: RopeSlice, mut begin: usize, count: usize) -> Option<Range> {
let mut end = begin;
for _ in 0..count {
if begin + 1 == slice.len_chars() {
return None;
}
let ch = slice.char(begin);
let next = slice.char(begin + 1);
if categorize(ch) != categorize(next) {
begin += 1;
}
// return if not skip while?
skip_over_next(slice, &mut begin, |ch| ch == '\n');
end = begin;
skip_over_next(slice, &mut end, is_horiz_blank);
// refetch
let ch = slice.char(end);
if is_word(ch) {
skip_over_next(slice, &mut end, is_word);
} else if ch.is_ascii_punctuation() {
skip_over_next(slice, &mut end, |ch| ch.is_ascii_punctuation());
}
}
Some(Range::new(begin, end - 1))
}
// ---- util ------------
// used for by-word movement
fn is_word(ch: char) -> bool {
ch.is_alphanumeric() || ch == '_'
}
fn is_horiz_blank(ch: char) -> bool {
matches!(ch, ' ' | '\t')
}
#[derive(Debug, Eq, PartialEq)]
enum Category {
Whitespace,
Eol,
Word,
Punctuation,
}
fn categorize(ch: char) -> Category {
if ch == '\n' {
Category::Eol
} else if ch.is_ascii_whitespace() {
Category::Whitespace
} else if ch.is_ascii_punctuation() {
Category::Punctuation
} else if ch.is_ascii_alphanumeric() {
Category::Word
} else {
unreachable!()
}
}
#[inline]
pub fn skip_over_next<F>(slice: RopeSlice, pos: &mut usize, fun: F)
where
F: Fn(char) -> bool,
{
let mut chars = slice.chars_at(*pos);
for ch in chars {
if !fun(ch) {
break;
}
*pos += 1;
}
}
#[inline]
/// Returns true if the final pos matches the predicate.
pub fn skip_over_prev<F>(slice: RopeSlice, pos: &mut usize, fun: F) -> bool
where
F: Fn(char) -> bool,
{
// need to +1 so that prev() includes current char
let mut chars = slice.chars_at(*pos + 1);
while let Some(ch) = chars.prev() {
if !fun(ch) {
break;
}
*pos = pos.saturating_sub(1);
}
fun(slice.char(*pos))
}
#[cfg(test)]
mod test {
use super::*;
#[test]
fn test_vertical_move() {
let text = Rope::from("abcd\nefg\nwrs");
let slice = text.slice(..);
let pos = pos_at_coords(slice, (0, 4).into());
let range = Range::new(pos, pos);
assert_eq!(
coords_at_pos(
slice,
move_vertically(slice, range, Direction::Forward, 1, false).head
),
(1, 2).into()
);
}
}
|
