From c503d32b204f09b23d8ad94b891cc451f0dded84 Mon Sep 17 00:00:00 2001
From: alice pellerin <thealicepellerin@gmail.com>
Date: Wed, 18 Mar 2026 03:19:17 -0500
Subject: [PATCH] x/X

---
 src/action.rs | 42 +++++++++++++++++++++++++++++++++++++++++-
 src/config.rs |  6 ++++++
 src/main.rs   |  1 -
 3 files changed, 47 insertions(+), 2 deletions(-)

diff --git a/src/action.rs b/src/action.rs
index 2189375..a024424 100644
--- a/src/action.rs
+++ b/src/action.rs
@@ -1,4 +1,4 @@
-use std::cmp::min;
+use std::{cmp::min, mem::swap};
 
 use crate::{BYTES_PER_LINE, app::{App, Mode, PartialAction}};
 
@@ -37,6 +37,9 @@ pub enum Action {
 	MovePreviousWordStart,
 	
 	CollapseSelection,
+	
+	ExtendLineBelow,
+	ExtendLineAbove,
 }
 
 impl App {
@@ -75,6 +78,9 @@ impl App {
 			Action::MovePreviousWordStart => self.move_previous_word_start(),
 			
 			Action::CollapseSelection => self.collapse_selection(),
+			
+			Action::ExtendLineBelow => self.extend_line_below(),
+			Action::ExtendLineAbove => self.extend_line_above(),
 		}
 	}
 	
@@ -233,6 +239,40 @@ impl App {
 	const fn collapse_selection(&mut self) {
 		self.cursor.collapse();
 	}
+	
+	fn extend_line_below(&mut self) {
+		if self.cursor.tail > self.cursor.head {
+			swap(&mut self.cursor.head, &mut self.cursor.tail);
+		}
+		
+		if self.cursor.tail.is_multiple_of(BYTES_PER_LINE) &&
+           self.cursor.head % BYTES_PER_LINE == BYTES_PER_LINE - 1
+		{
+			self.cursor.head = min(
+				self.cursor.head + BYTES_PER_LINE,
+				self.contents.len() - 1
+			)
+		} else {
+			self.cursor.tail -= self.cursor.tail % BYTES_PER_LINE;
+			self.cursor.head += BYTES_PER_LINE - 1 - (self.cursor.head % BYTES_PER_LINE);
+		}
+	}
+	
+	fn extend_line_above(&mut self) {
+		if self.cursor.head > self.cursor.tail {
+			swap(&mut self.cursor.head, &mut self.cursor.tail);
+		}
+		
+		if self.cursor.head.is_multiple_of(BYTES_PER_LINE) &&
+		   (self.cursor.tail % BYTES_PER_LINE == BYTES_PER_LINE - 1 ||
+		    self.cursor.tail == self.contents.len() - 1)
+		{
+			self.cursor.head = self.cursor.head.saturating_sub(BYTES_PER_LINE);
+		} else {
+			self.cursor.head -= self.cursor.head % BYTES_PER_LINE;
+			self.cursor.tail += BYTES_PER_LINE - 1 - (self.cursor.tail % BYTES_PER_LINE);
+		}
+	}
 }
 
 // helpers
diff --git a/src/config.rs b/src/config.rs
index 2e15bd1..8bb351a 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -128,6 +128,9 @@ impl Default for Config {
 					("b".try_into().unwrap(), Action::MovePreviousWordStart),
 					
 					(";".try_into().unwrap(), Action::CollapseSelection),
+					
+					("x".try_into().unwrap(), Action::ExtendLineBelow),
+					("X".try_into().unwrap(), Action::ExtendLineAbove),
 				].into()),
 				(Some(PartialAction::Goto), [
 					("j".try_into().unwrap(), Action::GotoLineStart),
@@ -165,6 +168,9 @@ impl Default for Config {
 					// ("b".try_into().unwrap(), Action::ExtendPreviousWordStart),
 					
 					(";".try_into().unwrap(), Action::CollapseSelection),
+					
+					("x".try_into().unwrap(), Action::ExtendLineBelow),
+					("X".try_into().unwrap(), Action::ExtendLineAbove),
 				].into())
 			].into())
 		].into()
diff --git a/src/main.rs b/src/main.rs
index 1815973..5c5b8ca 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -17,7 +17,6 @@ const CHUNKS_PER_LINE: usize = BYTES_PER_LINE / BYTES_PER_CHUNK;
 
 // TODO:
 // - undo/redo
-// - x/X
 // - modes
 //   - select
 //   - insert