From 066e938ba083c0259ff411b681eca7bad30980df Mon Sep 17 00:00:00 2001
From: Michael Davis <mcarsondavis@gmail.com>
Date: Sun, 2 Feb 2025 20:46:14 -0500
Subject: [PATCH] Add `copy_between_registers` for interactive register copying

---
 book/src/generated/static-cmd.md |  1 +
 helix-term/src/commands.rs       | 36 ++++++++++++++++++++++++++++++++
 2 files changed, 37 insertions(+)

diff --git a/book/src/generated/static-cmd.md b/book/src/generated/static-cmd.md
index ed31f0b1f..af7515b8e 100644
--- a/book/src/generated/static-cmd.md
+++ b/book/src/generated/static-cmd.md
@@ -239,6 +239,7 @@
 | `wonly` | Close windows except current | normal: `` <C-w>o ``, `` <space>wo ``, `` <C-w><C-o> ``, `` <space>w<C-o> ``, select: `` <C-w>o ``, `` <space>wo ``, `` <C-w><C-o> ``, `` <space>w<C-o> `` |
 | `select_register` | Select register | normal: `` " ``, select: `` " `` |
 | `insert_register` | Insert register | insert: `` <C-r> `` |
+| `copy_between_registers` | Copy between two registers |  |
 | `align_view_middle` | Align view middle | normal: `` Zm ``, `` zm ``, select: `` Zm ``, `` zm `` |
 | `align_view_top` | Align view top | normal: `` Zt ``, `` zt ``, select: `` Zt ``, `` zt `` |
 | `align_view_center` | Align view center | normal: `` Zc ``, `` Zz ``, `` zc ``, `` zz ``, select: `` Zc ``, `` Zz ``, `` zc ``, `` zz `` |
diff --git a/helix-term/src/commands.rs b/helix-term/src/commands.rs
index cd296f867..19a22601e 100644
--- a/helix-term/src/commands.rs
+++ b/helix-term/src/commands.rs
@@ -532,6 +532,7 @@ impl MappableCommand {
         wonly, "Close windows except current",
         select_register, "Select register",
         insert_register, "Insert register",
+        copy_between_registers, "Copy between two registers",
         align_view_middle, "Align view middle",
         align_view_top, "Align view top",
         align_view_center, "Align view center",
@@ -5569,6 +5570,41 @@ fn insert_register(cx: &mut Context) {
     })
 }
 
+fn copy_between_registers(cx: &mut Context) {
+    cx.editor.autoinfo = Some(Info::from_registers(&cx.editor.registers));
+    cx.on_next_key(move |cx, event| {
+        cx.editor.autoinfo = None;
+
+        let Some(source) = event.char() else {
+            return;
+        };
+
+        let Some(values) = cx.editor.registers.read(source, cx.editor) else {
+            cx.editor.set_error(format!("register {source} is empty"));
+            return;
+        };
+        let values: Vec<_> = values.map(|value| value.to_string()).collect();
+
+        cx.editor.autoinfo = Some(Info::from_registers(&cx.editor.registers));
+        cx.on_next_key(move |cx, event| {
+            cx.editor.autoinfo = None;
+
+            let Some(dest) = event.char() else {
+                return;
+            };
+
+            let n_values = values.len();
+            match cx.editor.registers.write(dest, values) {
+                Ok(_) => cx.editor.set_status(format!(
+                    "yanked {n_values} value{} from register {source} to {dest}",
+                    if n_values == 1 { "" } else { "s" }
+                )),
+                Err(err) => cx.editor.set_error(err.to_string()),
+            }
+        });
+    });
+}
+
 fn align_view_top(cx: &mut Context) {
     let (view, doc) = current!(cx.editor);
     align_view(doc, view, Align::Top);