Refactor and expand special registers

book/src/keymap.md

@@ -291,7 +291,7 @@ This layer is a kludge of mappings, mostly pickers.
 | `w`     | Enter [window mode](#window-mode)                                       | N/A                                        |
 | `p`     | Paste system clipboard after selections                                 | `paste_clipboard_after`                    |
 | `P`     | Paste system clipboard before selections                                | `paste_clipboard_before`                   |
-| `y`     | Join and yank selections to clipboard                                   | `yank_joined_to_clipboard`                 |
+| `y`     | Yank selections to clipboard                                            | `yank_to_clipboard`                        |
 | `Y`     | Yank main selection to clipboard                                        | `yank_main_selection_to_clipboard`         |
 | `R`     | Replace selections by clipboard contents                                | `replace_selections_with_clipboard`        |
 | `/`     | Global search in workspace folder                                       | `global_search`                            |

book/src/usage.md

@@ -37,19 +37,35 @@ If a register is selected before invoking a change or delete command, the select
 - `"hc` - Store the selection in register `h` and then change it (delete and enter insert mode).
 - `"md` - Store the selection in register `m` and delete it.
 
-### Special registers
+### Default registers
+
+Commands that use registers, like yank (`y`), use a default register if none is specified.
+These registers are used as defaults:
 
 | Register character | Contains              |
 | ---                | ---                   |
 | `/`                | Last search           |
 | `:`                | Last executed command |
 | `"`                | Last yanked text      |
-| `_`                | Black hole            |
+| `@`                | Last recorded macro   |
 
-The system clipboard is not directly supported by a special register. Instead, special commands and keybindings are provided. Refer to the
-[key map](keymap.md#space-mode) for more details.
+### Special registers
 
-The black hole register is a no-op register, meaning that no data will be read or written to it.
+Some registers have special behavior when read from and written to.
+
+| Register character | When read              | When written             |
+| ---                | ---                    | ---                      |
+| `_`                | No values are returned | All values are discarded |
+| `#`                | Selection indices (first selection is `1`, second is `2`, etc.) | This register is not writable |
+| `.`                | Contents of the current selections | This register is not writable |
+| `%`                | Name of the current file | This register is not writable |
+| `*`                | Reads from the system clipboard | Joins and yanks to the system clipboard |
+| `+`                | Reads from the primary clipboard | Joins and yanks to the primary clipboard |
+
+When yanking multiple selections to the clipboard registers, the selections
+are joined with newlines. Pasting from these registers will paste multiple
+selections if the clipboard was last yanked to by the Helix session. Otherwise
+the clipboard contents are pasted as one selection.
 
 ## Surround
 

helix-core/src/lib.rs

@@ -18,7 +18,6 @@ pub mod movement;
 pub mod object;
 pub mod path;
 mod position;
-pub mod register;
 pub mod search;
 pub mod selection;
 pub mod shellwords;

helix-core/src/selection.rs

@@ -630,11 +630,19 @@ impl Selection {
         self.transform(|range| Range::point(range.cursor(text)))
     }
 
-    pub fn fragments<'a>(&'a self, text: RopeSlice<'a>) -> impl Iterator<Item = Cow<str>> + 'a {
+    pub fn fragments<'a>(
+        &'a self,
+        text: RopeSlice<'a>,
+    ) -> impl DoubleEndedIterator<Item = Cow<'a, str>> + ExactSizeIterator<Item = Cow<str>> + 'a
+    {
         self.ranges.iter().map(move |range| range.fragment(text))
     }
 
-    pub fn slices<'a>(&'a self, text: RopeSlice<'a>) -> impl Iterator<Item = RopeSlice> + 'a {
+    pub fn slices<'a>(
+        &'a self,
+        text: RopeSlice<'a>,
+    ) -> impl DoubleEndedIterator<Item = RopeSlice<'a>> + ExactSizeIterator<Item = RopeSlice<'a>> + 'a
+    {
         self.ranges.iter().map(move |range| range.slice(text))
     }