Replace line endings using `set_line_ending` command (#1871)

* set_line_ending: now replace line endings

* use ending.len_chars() directly

* account for unicode-lines feaure in line-ending doc

book/src/generated/typable-cmd.md

@@ -16,7 +16,7 @@
 | `:new`, `:n` | Create a new scratch buffer. |
 | `:format`, `:fmt` | Format the file using the LSP formatter. |
 | `:indent-style` | Set the indentation style for editing. ('t' for tabs or 1-8 for number of spaces.) |
-| `:line-ending` | Set the document's default line ending. Options: crlf, lf, cr, ff, nel. |
+| `:line-ending` | Set the document's default line ending. Options: crlf, lf. |
 | `:earlier`, `:ear` | Jump back to an earlier point in edit history. Accepts a number of steps or a time span. |
 | `:later`, `:lat` | Jump to a later point in edit history. Accepts a number of steps or a time span. |
 | `:write-quit`, `:wq`, `:x` | Write changes to disk and close the current view. Accepts an optional path (:wq some/path.txt) |

helix-term/src/commands/typed.rs

@@ -352,8 +352,26 @@ fn set_line_ending(
         arg if arg.starts_with("nel") => Nel,
         _ => bail!("invalid line ending"),
     };
+    let (view, doc) = current!(cx.editor);
+    doc.line_ending = line_ending;
+
+    let mut pos = 0;
+    let transaction = Transaction::change(
+        doc.text(),
+        doc.text().lines().filter_map(|line| {
+            pos += line.len_chars();
+            match helix_core::line_ending::get_line_ending(&line) {
+                Some(ending) if ending != line_ending => {
+                    let start = pos - ending.len_chars();
+                    let end = pos;
+                    Some((start, end, Some(line_ending.as_str().into())))
+                }
+                _ => None,
+            }
+        }),
+    );
+    doc.apply(&transaction, view.id);
 
-    doc_mut!(cx.editor).line_ending = line_ending;
     Ok(())
 }
 
@@ -1193,6 +1211,9 @@ pub const TYPABLE_COMMAND_LIST: &[TypableCommand] = &[
         TypableCommand {
             name: "line-ending",
             aliases: &[],
+            #[cfg(not(feature = "unicode-lines"))]
+            doc: "Set the document's default line ending. Options: crlf, lf.",
+            #[cfg(feature = "unicode-lines")]
             doc: "Set the document's default line ending. Options: crlf, lf, cr, ff, nel.",
             fun: set_line_ending,
             completer: None,