From f6617c14d31479bb14cc21df1939d33efa658c83 Mon Sep 17 00:00:00 2001
From: Jonathan LEI <me@xjonathan.dev>
Date: Sat, 7 Jan 2023 07:04:49 +0000
Subject: [PATCH] Make mouse click extend selection in select mode

---
 helix-term/src/ui/editor.rs | 40 +++++++++++++++++++++++++++----------
 helix-view/src/editor.rs    |  7 +++++--
 2 files changed, 34 insertions(+), 13 deletions(-)

diff --git a/helix-term/src/ui/editor.rs b/helix-term/src/ui/editor.rs
index f297b44eb08b0..ebcdc526cf629 100644
--- a/helix-term/src/ui/editor.rs
+++ b/helix-term/src/ui/editor.rs
@@ -1040,6 +1040,15 @@ impl EditorView {
                     if modifiers == KeyModifiers::ALT {
                         let selection = doc.selection(view_id).clone();
                         doc.set_selection(view_id, selection.push(Range::point(pos)));
+                    } else if editor.mode == Mode::Select {
+                        // Discards non-primary selections for consistent UX with normal mode
+                        let primary = doc.selection(view_id).primary().put_cursor(
+                            doc.text().slice(..),
+                            pos,
+                            true,
+                        );
+                        editor.mouse_down_range = Some(primary);
+                        doc.set_selection(view_id, Selection::single(primary.anchor, primary.head));
                     } else {
                         doc.set_selection(view_id, Selection::point(pos));
                     }
@@ -1119,19 +1128,28 @@ impl EditorView {
 
                 let (view, doc) = current!(cxt.editor);
 
-                if doc
-                    .selection(view.id)
-                    .primary()
-                    .slice(doc.text().slice(..))
-                    .len_chars()
-                    <= 1
-                {
-                    return EventResult::Ignored(None);
-                }
+                let should_yank = match cxt.editor.mouse_down_range {
+                    Some(down_range) => doc.selection(view.id).primary() != down_range,
+                    None => {
+                        // This should not happen under normal cases. We fall back to the original
+                        // behavior of yanking on non-single-char selections.
+                        doc.selection(view.id)
+                            .primary()
+                            .slice(doc.text().slice(..))
+                            .len_chars()
+                            > 1
+                    }
+                };
 
-                commands::MappableCommand::yank_main_selection_to_primary_clipboard.execute(cxt);
+                cxt.editor.mouse_down_range = None;
 
-                EventResult::Consumed(None)
+                if should_yank {
+                    commands::MappableCommand::yank_main_selection_to_primary_clipboard
+                        .execute(cxt);
+                    EventResult::Consumed(None)
+                } else {
+                    EventResult::Ignored(None)
+                }
             }
 
             MouseEventKind::Up(MouseButton::Right) => {
diff --git a/helix-view/src/editor.rs b/helix-view/src/editor.rs
index 46511c62d73f6..d52de21e02071 100644
--- a/helix-view/src/editor.rs
+++ b/helix-view/src/editor.rs
@@ -44,7 +44,7 @@ use helix_core::Position;
 use helix_core::{
     auto_pairs::AutoPairs,
     syntax::{self, AutoPairConfig},
-    Change,
+    Change, Range,
 };
 use helix_dap as dap;
 use helix_lsp::lsp;
@@ -867,6 +867,8 @@ pub struct Editor {
     /// avoid calculating the cursor position multiple
     /// times during rendering and should not be set by other functions.
     pub cursor_cache: Cell<Option<Option<Position>>>,
+
+    pub mouse_down_range: Option<Range>,
 }
 
 pub type RedrawHandle = (Arc<Notify>, Arc<RwLock<()>>);
@@ -965,6 +967,7 @@ impl Editor {
             redraw_handle: Default::default(),
             needs_redraw: false,
             cursor_cache: Cell::new(None),
+            mouse_down_range: None,
         }
     }
 
@@ -1597,7 +1600,7 @@ impl Editor {
 
     /// Switches the editor into normal mode.
     pub fn enter_normal_mode(&mut self) {
-        use helix_core::{graphemes, Range};
+        use helix_core::graphemes;
 
         if self.mode == Mode::Normal {
             return;