add_newline unimpaired mapping (#653)

* added some keymaps

* remove

* remove wrong mappings

* remove

* wrong import

* use enum

* correct line ending

* added to book

* column

3 files changed, 50 insertions, 11 deletions

diff --git a/book/src/keymap.md b/book/src/keymap.md
index 2c6a9576..861e46ac 100644
--- a/book/src/keymap.md
+++ b/book/src/keymap.md
@@ -110,17 +110,18 @@ in reverse, or searching via smartcase.
 | `N`   | Add next search match to selection          | `extend_search_next` |
 | `*`   | Use current selection as the search pattern | `search_selection`   |
 
-### Diagnostics
-
-> NOTE: `[` and `]` will likely contain more pair mappings in the style of
-> [vim-unimpaired](https://github.com/tpope/vim-unimpaired)
-
-| Key   | Description                        | Command           |
-| ----- | -----------                        | -------           |
-| `[d`  | Go to previous diagnostic          | `goto_prev_diag`  |
-| `]d`  | Go to next diagnostic              | `goto_next_diag`  |
-| `[D`  | Go to first diagnostic in document | `goto_first_diag` |
-| `]D`  | Go to last diagnostic in document  | `goto_last_diag`  |
+### Unimpaired
+
+Mappings in the style of [vim-unimpaired](https://github.com/tpope/vim-unimpaired)
+
+| Key       | Description                        | Command           |
+| -----     | -----------                        | -------           |
+| `[d`      | Go to previous diagnostic          | `goto_prev_diag`  |
+| `]d`      | Go to next diagnostic              | `goto_next_diag`  |
+| `[D`      | Go to first diagnostic in document | `goto_first_diag` |
+| `]D`      | Go to last diagnostic in document  | `goto_last_diag`  |
+| `[space`  | Add newline above                  | `add_newline_above` |
+| `]space`  | Add newline below                  | `add_newline_below` |
 
 ### Shell
 
diff --git a/helix-term/src/commands.rs b/helix-term/src/commands.rs
index 5574afbf..3bd63ab4 100644
--- a/helix-term/src/commands.rs
+++ b/helix-term/src/commands.rs
@@ -227,6 +227,8 @@ impl Command {
         select_mode, "Enter selection extend mode",
         exit_select_mode, "Exit selection mode",
         goto_definition, "Goto definition",
+        add_newline_above, "Add newline above",
+        add_newline_below, "Add newline below",
         goto_type_definition, "Goto type definition",
         goto_implementation, "Goto implementation",
         goto_file_start, "Goto file start/line",
@@ -4473,3 +4475,37 @@ fn suspend(_cx: &mut Context) {
     #[cfg(not(windows))]
     signal_hook::low_level::raise(signal_hook::consts::signal::SIGTSTP).unwrap();
 }
+
+fn add_newline_above(cx: &mut Context) {
+    add_newline_impl(cx, Open::Above);
+}
+
+fn add_newline_below(cx: &mut Context) {
+    add_newline_impl(cx, Open::Below)
+}
+
+fn add_newline_impl(cx: &mut Context, open: Open) {
+    let count = cx.count();
+    let (view, doc) = current!(cx.editor);
+    let selection = doc.selection(view.id);
+    let text = doc.text();
+    let slice = text.slice(..);
+
+    let changes = selection.into_iter().map(|range| {
+        let (start, end) = range.line_range(slice);
+        let line = match open {
+            Open::Above => start,
+            Open::Below => end + 1,
+        };
+        let pos = text.line_to_char(line);
+        (
+            pos,
+            pos,
+            Some(doc.line_ending.as_str().repeat(count).into()),
+        )
+    });
+
+    let transaction = Transaction::change(text, changes);
+    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 f3e160b1..71ac01a9 100644
--- a/helix-term/src/keymap.rs
+++ b/helix-term/src/keymap.rs
@@ -412,10 +412,12 @@ impl Default for Keymaps {
             "[" => { "Left bracket"
                 "d" => goto_prev_diag,
                 "D" => goto_first_diag,
+                "space" => add_newline_above,
             },
             "]" => { "Right bracket"
                 "d" => goto_next_diag,
                 "D" => goto_last_diag,
+                "space" => add_newline_below,
             },
 
             "/" => search,