From b7c3877e947d95ee0fd9b1653dab6f65bb340439 Mon Sep 17 00:00:00 2001
From: Ivan Tham
Date: Sun, 14 Nov 2021 23:16:47 +0800
Subject: Add movement shortcut for history (#1088)

alt-u and alt-U---
 book/src/keymap.md         |  2 ++
 helix-core/src/history.rs  |  2 +-
 helix-term/src/commands.rs | 60 +++++++++++++++++++++++++++++++++-------------
 helix-term/src/keymap.rs   |  2 ++
 4 files changed, 48 insertions(+), 18 deletions(-)

diff --git a/book/src/keymap.md b/book/src/keymap.md
index 69f5f02c..88610a77 100644
--- a/book/src/keymap.md
+++ b/book/src/keymap.md
@@ -61,6 +61,8 @@
 | `.`         | Repeat last change                              | N/A                   |
 | `u`         | Undo change                                     | `undo`                |
 | `U`         | Redo change                                     | `redo`                |
+| `Alt-u`     | Move backward in history                        | `earlier`             |
+| `Alt-U`     | Move forward in history                         | `later`               |
 | `y`         | Yank selection                                  | `yank`                |
 | `p`         | Paste after selection                           | `paste_after`         |
 | `P`         | Paste before selection                          | `paste_before`        |
diff --git a/helix-core/src/history.rs b/helix-core/src/history.rs
index 9fe7e530..4b1c8d3b 100644
--- a/helix-core/src/history.rs
+++ b/helix-core/src/history.rs
@@ -282,7 +282,7 @@ impl History {
 }
 
 /// Whether to undo by a number of edits or a duration of time.
-#[derive(Debug, PartialEq)]
+#[derive(Debug, PartialEq, Clone, Copy)]
 pub enum UndoKind {
     Steps(usize),
     TimePeriod(std::time::Duration),
diff --git a/helix-term/src/commands.rs b/helix-term/src/commands.rs
index 56cc02a2..115d1789 100644
--- a/helix-term/src/commands.rs
+++ b/helix-term/src/commands.rs
@@ -1,5 +1,7 @@
 use helix_core::{
-    comment, coords_at_pos, find_first_non_whitespace_char, find_root, graphemes, indent,
+    comment, coords_at_pos, find_first_non_whitespace_char, find_root, graphemes,
+    history::UndoKind,
+    indent,
     indent::IndentStyle,
     line_ending::{get_line_ending_of_str, line_end_char_index, str_is_line_ending},
     match_brackets,
@@ -284,6 +286,8 @@ impl Command {
         delete_word_backward, "Delete previous word",
         undo, "Undo change",
         redo, "Redo change",
+        earlier, "Move backward in history",
+        later, "Move forward in history",
         yank, "Yank selection",
         yank_joined_to_clipboard, "Join and yank selections to clipboard",
         yank_main_selection_to_clipboard, "Yank main selection to clipboard",
@@ -1877,10 +1881,7 @@ mod cmd {
         args: &[&str],
         _event: PromptEvent,
     ) -> anyhow::Result<()> {
-        let uk = args
-            .join(" ")
-            .parse::<helix_core::history::UndoKind>()
-            .map_err(|s| anyhow!(s))?;
+        let uk = args.join(" ").parse::<UndoKind>().map_err(|s| anyhow!(s))?;
 
         let (view, doc) = current!(cx.editor);
         let success = doc.earlier(view.id, uk);
@@ -1896,10 +1897,7 @@ mod cmd {
         args: &[&str],
         _event: PromptEvent,
     ) -> anyhow::Result<()> {
-        let uk = args
-            .join(" ")
-            .parse::<helix_core::history::UndoKind>()
-            .map_err(|s| anyhow!(s))?;
+        let uk = args.join(" ").parse::<UndoKind>().map_err(|s| anyhow!(s))?;
         let (view, doc) = current!(cx.editor);
         let success = doc.later(view.id, uk);
         if !success {
@@ -3963,20 +3961,48 @@ pub mod insert {
 // storing it?
 
 fn undo(cx: &mut Context) {
+    let count = cx.count();
     let (view, doc) = current!(cx.editor);
-    let view_id = view.id;
-    let success = doc.undo(view_id);
-    if !success {
-        cx.editor.set_status("Already at oldest change".to_owned());
+    for _ in 0..count {
+        if !doc.undo(view.id) {
+            cx.editor.set_status("Already at oldest change".to_owned());
+            break;
+        }
     }
 }
 
 fn redo(cx: &mut Context) {
+    let count = cx.count();
+    let (view, doc) = current!(cx.editor);
+    for _ in 0..count {
+        if !doc.redo(view.id) {
+            cx.editor.set_status("Already at newest change".to_owned());
+            break;
+        }
+    }
+}
+
+fn earlier(cx: &mut Context) {
+    let count = cx.count();
+    let (view, doc) = current!(cx.editor);
+    for _ in 0..count {
+        // rather than doing in batch we do this so get error halfway
+        if !doc.earlier(view.id, UndoKind::Steps(1)) {
+            cx.editor.set_status("Already at oldest change".to_owned());
+            break;
+        }
+    }
+}
+
+fn later(cx: &mut Context) {
+    let count = cx.count();
     let (view, doc) = current!(cx.editor);
-    let view_id = view.id;
-    let success = doc.redo(view_id);
-    if !success {
-        cx.editor.set_status("Already at newest change".to_owned());
+    for _ in 0..count {
+        // rather than doing in batch we do this so get error halfway
+        if !doc.later(view.id, UndoKind::Steps(1)) {
+            cx.editor.set_status("Already at newest change".to_owned());
+            break;
+        }
     }
 }
 
diff --git a/helix-term/src/keymap.rs b/helix-term/src/keymap.rs
index fc9fd590..010714dc 100644
--- a/helix-term/src/keymap.rs
+++ b/helix-term/src/keymap.rs
@@ -582,6 +582,8 @@ impl Default for Keymaps {
 
             "u" => undo,
             "U" => redo,
+            "A-u" => earlier,
+            "A-U" => later,
 
             "y" => yank,
             // yank_all
-- 
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