From 12961d657f9ca78f54156457ed27732e60992734 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bla=C5=BE=20Hrastnik?= <blaz@mxxn.io>
Date: Wed, 7 Apr 2021 17:03:29 +0900
Subject: [PATCH] Implement P as paste_before.

---
 helix-term/src/commands.rs | 79 ++++++++++++++++++++++++--------------
 helix-term/src/keymap.rs   |  3 +-
 2 files changed, 53 insertions(+), 29 deletions(-)

diff --git a/helix-term/src/commands.rs b/helix-term/src/commands.rs
index 0d5ffb9c0..d84103528 100644
--- a/helix-term/src/commands.rs
+++ b/helix-term/src/commands.rs
@@ -1405,7 +1405,13 @@ pub fn yank(cx: &mut Context) {
     cx.set_status(msg)
 }
 
-pub fn paste(cx: &mut Context) {
+#[derive(Copy, Clone)]
+enum Paste {
+    Before,
+    After,
+}
+
+fn _paste(doc: &mut Document, view: &View, action: Paste) -> Option<Transaction> {
     // TODO: allow specifying reg
     let reg = '"';
     if let Some(values) = register::get(reg) {
@@ -1416,40 +1422,57 @@ pub fn paste(cx: &mut Context) {
                 .unwrap(),
         );
 
-        // TODO: if any of values ends \n it's linewise paste
-        //
-        // p => paste after
-        // P => paste before
-        // alt-p => paste every yanked selection after selected text
-        // alt-P => paste every yanked selection before selected text
-        // R => replace selected text with yanked text
-        // alt-R => replace selected text with every yanked text
-        //
-        // append => insert at next line
-        // insert => insert at start of line
-        // replace => replace
-        // default insert
-
+        // if any of values ends \n it's linewise paste
         let linewise = values.iter().any(|value| value.ends_with('\n'));
 
         let mut values = values.into_iter().map(Tendril::from).chain(repeat);
 
-        let (view, doc) = cx.current();
+        // paste on the next line
+        // TODO: can simply take a range + modifier and compute the right pos without ifs
+        let text = doc.text();
 
-        let transaction = if linewise {
-            // paste on the next line
-            // TODO: can simply take a range + modifier and compute the right pos without ifs
-            let text = doc.text();
-            Transaction::change_by_selection(doc.text(), doc.selection(view.id), |range| {
-                let line_end = text.line_to_char(text.char_to_line(range.head) + 1);
-                (line_end, line_end, Some(values.next().unwrap()))
-            })
-        } else {
+        let transaction =
             Transaction::change_by_selection(doc.text(), doc.selection(view.id), |range| {
-                (range.head + 1, range.head + 1, Some(values.next().unwrap()))
-            })
-        };
+                let pos = match (action, linewise) {
+                    // paste linewise before
+                    (Paste::Before, true) => text.line_to_char(text.char_to_line(range.from())),
+                    // paste linewise after
+                    (Paste::After, true) => text.line_to_char(text.char_to_line(range.to()) + 1),
+                    // paste insert
+                    (Paste::Before, false) => range.from(),
+                    // paste append
+                    (Paste::After, false) => range.to() + 1,
+                };
+                (pos, pos, Some(values.next().unwrap()))
+            });
+        return Some(transaction);
+    }
+    None
+}
+
+// alt-p => paste every yanked selection after selected text
+// alt-P => paste every yanked selection before selected text
+// R => replace selected text with yanked text
+// alt-R => replace selected text with every yanked text
+//
+// append => insert at next line
+// insert => insert at start of line
+// replace => replace
+// default insert
+
+pub fn paste_after(cx: &mut Context) {
+    let (view, doc) = cx.current();
+
+    if let Some(transaction) = _paste(doc, view, Paste::After) {
+        doc.apply(&transaction, view.id);
+        doc.append_changes_to_history(view.id);
+    }
+}
+
+pub fn paste_before(cx: &mut Context) {
+    let (view, doc) = cx.current();
 
+    if let Some(transaction) = _paste(doc, view, Paste::Before) {
         doc.apply(&transaction, view.id);
         doc.append_changes_to_history(view.id);
     }
diff --git a/helix-term/src/keymap.rs b/helix-term/src/keymap.rs
index eeecd08e2..06b190aa8 100644
--- a/helix-term/src/keymap.rs
+++ b/helix-term/src/keymap.rs
@@ -207,8 +207,9 @@ pub fn default() -> Keymaps {
 
         key!('y') => commands::yank,
         // yank_all
-        key!('p') => commands::paste,
+        key!('p') => commands::paste_after,
         // paste_all
+        shift!('P') => commands::paste_before,
 
         key!('>') => commands::indent,
         key!('<') => commands::unindent,