From 96db02742e85648e4ce0c2ab9b7cd239bdb763f8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bla=C5=BE=20Hrastnik?= <blaz@mxxn.io>
Date: Sun, 13 Sep 2020 23:38:54 +0900
Subject: [PATCH] Simplify some more code.

---
 helix-core/src/commands.rs    |  2 +-
 helix-core/src/selection.rs   | 12 ++++++++++--
 helix-core/src/state.rs       | 15 ++++-----------
 helix-core/src/transaction.rs | 10 +---------
 4 files changed, 16 insertions(+), 23 deletions(-)

diff --git a/helix-core/src/commands.rs b/helix-core/src/commands.rs
index 8dc817da8..6c09c3adf 100644
--- a/helix-core/src/commands.rs
+++ b/helix-core/src/commands.rs
@@ -62,8 +62,8 @@ pub fn append_mode(state: &mut State, _count: usize) {
 
 // TODO: I, A, o and O can share a lot of the primitives.
 
+// calculate line numbers for each selection range
 fn selection_lines(state: &State) -> Vec<usize> {
-    // calculate line numbers for each selection range
     let mut lines = state
         .selection
         .ranges()
diff --git a/helix-core/src/selection.rs b/helix-core/src/selection.rs
index 2ae2d7c8d..80bb6a0c1 100644
--- a/helix-core/src/selection.rs
+++ b/helix-core/src/selection.rs
@@ -100,8 +100,8 @@ pub fn extend(&self, from: usize, to: usize) -> Self {
 #[derive(Debug, Clone)]
 pub struct Selection {
     // TODO: decide how many ranges to inline SmallVec<[Range; 1]>
-    pub(crate) ranges: SmallVec<[Range; 1]>,
-    pub(crate) primary_index: usize,
+    ranges: SmallVec<[Range; 1]>,
+    primary_index: usize,
 }
 
 impl Selection {
@@ -205,6 +205,14 @@ pub fn single(anchor: usize, head: usize) -> Self {
             }
         }
 
+        // fast path for a single selection (cursor)
+        if ranges.len() == 1 {
+            return Selection {
+                ranges,
+                primary_index: 0,
+            };
+        }
+
         // TODO: only normalize if needed (any ranges out of order)
         normalize(ranges, primary_index)
     }
diff --git a/helix-core/src/state.rs b/helix-core/src/state.rs
index 511df8fec..be2b33172 100644
--- a/helix-core/src/state.rs
+++ b/helix-core/src/state.rs
@@ -122,7 +122,7 @@ pub fn move_selection(
         // TODO: move all selections according to normal cursor move semantics by collapsing it
         // into cursors and moving them vertically
 
-        let ranges = self.selection.ranges.iter().map(|range| {
+        self.selection.transform(|range| {
             // let pos = if !range.is_empty() {
             //     // if selection already exists, bump it to the start or end of current select first
             //     if dir == Direction::Backward {
@@ -134,10 +134,7 @@ pub fn move_selection(
             let pos = self.move_pos(range.head, dir, granularity, count);
             // };
             SelectionRange::new(pos, pos)
-        });
-
-        Selection::new(ranges.collect(), self.selection.primary_index)
-        // TODO: update selection in state via transaction
+        })
     }
 
     pub fn extend_selection(
@@ -146,13 +143,10 @@ pub fn extend_selection(
         granularity: Granularity,
         count: usize,
     ) -> Selection {
-        let ranges = self.selection.ranges.iter().map(|range| {
+        self.selection.transform(|range| {
             let pos = self.move_pos(range.head, dir, granularity, count);
             SelectionRange::new(range.anchor, pos)
-        });
-
-        Selection::new(ranges.collect(), self.selection.primary_index)
-        // TODO: update selection in state via transaction
+        })
     }
 }
 
@@ -203,7 +197,6 @@ mod test {
     fn test_coords_at_pos() {
         let text = Rope::from("ḧëḷḷö\nẅöṛḷḋ");
         assert_eq!(coords_at_pos(&text.slice(..), 0), (0, 0));
-        // TODO: what is the coordinate of newline?
         assert_eq!(coords_at_pos(&text.slice(..), 5), (0, 5)); // position on \n
         assert_eq!(coords_at_pos(&text.slice(..), 6), (1, 0)); // position on w
         assert_eq!(coords_at_pos(&text.slice(..), 7), (1, 1)); // position on o
diff --git a/helix-core/src/transaction.rs b/helix-core/src/transaction.rs
index 4ecc575a8..b4cc83c6a 100644
--- a/helix-core/src/transaction.rs
+++ b/helix-core/src/transaction.rs
@@ -3,13 +3,6 @@
 /// (from, to, replacement)
 pub type Change = (usize, usize, Option<Tendril>);
 
-// TODO: divided into three different operations, I sort of like having just
-// Splice { extent, Option<text>, distance } better.
-// insert: Splice { extent: 0, text: Some("a"), distance: 2 }
-// delete: Splice { extent: 2, text: None, distance: 2 }
-// replace: Splice { extent: 2, text: Some("abc"), distance: 2 }
-// unchanged?: Splice { extent: 0, text: None, distance: 2 }
-// harder to compose though.
 #[derive(Debug, Clone, PartialEq, Eq)]
 enum Operation {
     /// Move cursor by n characters.
@@ -364,7 +357,6 @@ pub fn change<I>(state: &State, changes: I) -> Self
 
         let mut last = 0;
         for (from, to, tendril) in changes {
-            // TODO: need to fill the in-between ranges too
             // Retain from last "to" to current "from"
             acc.push(Operation::Retain(from - last));
             match tendril {
@@ -383,7 +375,7 @@ pub fn change_by_selection<F>(state: &State, f: F) -> Self
     where
         F: Fn(&SelectionRange) -> Change,
     {
-        Self::change(state, state.selection.ranges.iter().map(f))
+        Self::change(state, state.selection.ranges().iter().map(f))
     }
 
     /// Insert text at each selection head.