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authorNathan Vegdahl2021-07-08 00:24:39 +0000
committerNathan Vegdahl2021-07-08 00:24:39 +0000
commit753f7f381b96f591be3c0e37a93b90776c5405cb (patch)
tree749a0ac3a0f5a15b5fa8a8be70d2182cb79cf500 /helix-core/src
parent85d5b399de70ff075a455ce2858549d1ed012fe3 (diff)
Implement `Range::put()` which manages range movements and extensions.
In particular, this wraps the annoying logic involved in keeping the cursor width to 1 grapheme.
Diffstat (limited to 'helix-core/src')
-rw-r--r--helix-core/src/movement.rs91
-rw-r--r--helix-core/src/selection.rs23
2 files changed, 49 insertions, 65 deletions
diff --git a/helix-core/src/movement.rs b/helix-core/src/movement.rs
index bc56f9a4..0e2a2a42 100644
--- a/helix-core/src/movement.rs
+++ b/helix-core/src/movement.rs
@@ -32,60 +32,31 @@ pub fn move_horizontally(
count: usize,
behaviour: Movement,
) -> Range {
- match (behaviour, dir) {
- (Movement::Move, Direction::Backward) => {
- let count = if range.anchor < range.head {
- count + 1
- } else {
- count
- };
- let pos = nth_prev_grapheme_boundary(slice, range.head, count);
- Range::new(pos, pos)
- }
- (Movement::Move, Direction::Forward) => {
- let count = if range.anchor < range.head {
- count - 1
- } else {
- count
- };
- let pos = nth_next_grapheme_boundary(slice, range.head, count);
- Range::new(pos, pos)
- }
- (Movement::Extend, Direction::Backward) => {
- // Ensure a valid initial selection state.
- let range = range.min_width_1(slice);
-
- // Do the main movement.
- let mut head = nth_prev_grapheme_boundary(slice, range.head, count);
- let mut anchor = range.anchor;
-
- // If the head and anchor crossed over each other, we need to
- // fiddle around to make it behave like a 1-wide cursor.
- if head <= anchor && range.head > range.anchor {
- anchor = next_grapheme_boundary(slice, anchor);
- head = prev_grapheme_boundary(slice, head);
- }
+ use Movement::Extend;
- Range::new(anchor, head)
- }
- (Movement::Extend, Direction::Forward) => {
- // Ensure a valid initial selection state.
- let range = range.min_width_1(slice);
-
- // Do the main movement.
- let mut head = nth_next_grapheme_boundary(slice, range.head, count);
- let mut anchor = range.anchor;
-
- // If the head and anchor crossed over each other, we need to
- // fiddle around to make it behave like a 1-wide cursor.
- if head >= anchor && range.head < range.anchor {
- anchor = prev_grapheme_boundary(slice, anchor);
- head = next_grapheme_boundary(slice, head);
- }
+ // Shift back one grapheme if needed, to account for
+ // the cursor being visually 1-width.
+ let pos = if range.head > range.anchor {
+ prev_grapheme_boundary(slice, range.head)
+ } else {
+ range.head
+ };
- Range::new(anchor, head)
- }
- }
+ // Compute the new position.
+ let mut new_pos = if dir == Direction::Backward {
+ nth_prev_grapheme_boundary(slice, pos, count)
+ } else {
+ nth_next_grapheme_boundary(slice, pos, count)
+ };
+
+ // Shift forward one grapheme if needed, for the
+ // visual 1-width cursor.
+ if behaviour == Extend && new_pos >= range.anchor {
+ new_pos = next_grapheme_boundary(slice, new_pos);
+ };
+
+ // Compute the final new range.
+ range.put(slice, behaviour == Extend, new_pos)
}
pub fn move_vertically(
@@ -135,19 +106,9 @@ pub fn move_vertically(
new_pos
};
- let new_anchor = if range.anchor <= range.head && range.anchor > new_head {
- next_grapheme_boundary(slice, range.anchor)
- } else if range.anchor > range.head && range.anchor < new_head {
- prev_grapheme_boundary(slice, range.anchor)
- } else {
- range.anchor
- };
-
- Range {
- anchor: new_anchor,
- head: new_head,
- horiz: Some(horiz),
- }
+ let mut new_range = range.put(slice, true, new_head);
+ new_range.horiz = Some(horiz);
+ new_range
}
}
}
diff --git a/helix-core/src/selection.rs b/helix-core/src/selection.rs
index 64ff51d8..8951899b 100644
--- a/helix-core/src/selection.rs
+++ b/helix-core/src/selection.rs
@@ -5,6 +5,7 @@
use crate::{
graphemes::{
ensure_grapheme_boundary_next, ensure_grapheme_boundary_prev, next_grapheme_boundary,
+ prev_grapheme_boundary,
},
Assoc, ChangeSet, RopeSlice,
};
@@ -208,6 +209,28 @@ impl Range {
}
}
+ /// Moves the `Range` to `char_idx`. If `extend == true`, then only the head
+ /// is moved to `char_idx`, and the anchor is adjusted only as needed to
+ /// preserve 1-width range semantics.
+ ///
+ /// This method assumes that the range and `char_idx` are already properly
+ /// grapheme-aligned.
+ #[must_use]
+ #[inline]
+ pub fn put(self, text: RopeSlice, extend: bool, char_idx: usize) -> Range {
+ let anchor = if !extend {
+ char_idx
+ } else if self.head >= self.anchor && char_idx < self.anchor {
+ next_grapheme_boundary(text, self.anchor)
+ } else if self.head < self.anchor && char_idx >= self.anchor {
+ prev_grapheme_boundary(text, self.anchor)
+ } else {
+ self.anchor
+ };
+
+ Range::new(anchor, char_idx)
+ }
+
// groupAt
#[inline]