documents: the selected Markdown, in source or an open block

src/documents/document/place.rs

@@ -28,6 +28,16 @@ impl MarkdownDocument {
         point(&self.text(cx), open.range.start + joined + input.cursor())
     }
 
+    /// The selected Markdown: the source's, or the open block's.
+    pub fn selected(&self, cx: &App) -> String {
+        let Some(open) = &self.open else {
+            let editor = self.editor.read(cx);
+            return editor.text()[editor.primary().range()].to_string();
+        };
+        let input = open.input.read(cx);
+        input.text()[input.selection()].to_string()
+    }
+
     /// The caret to `line` and `column`, clamped to text.
     pub fn set_caret(&mut self, line: usize, column: usize, cx: &mut Context<Self>) {
         self.commit(cx);

src/documents/document/tests/place.rs

@@ -198,3 +198,30 @@ fn a_reset_keeps_the_caret_and_the_top_line(cx: &mut TestAppContext) {
     });
     assert_eq!((caret, top), ((40, 2), 30));
 }
+
+#[gpui::test]
+fn the_selection_reads_in_source_and_in_an_open_block(cx: &mut TestAppContext) {
+    let (document, cx) = open("# One\n\nTwo words.\n", MarkdownMode::Source, cx);
+    document.update(cx, |document, cx| {
+        document
+            .editor
+            .update(cx, |editor, cx| editor.select(std::iter::once(2..5), cx))
+    });
+    assert_eq!(
+        document.read_with(cx, |document, cx| document.selected(cx)),
+        "One"
+    );
+    document.update_in(cx, |document, window, cx| {
+        document.set_mode(MarkdownMode::Visual, window, cx)
+    });
+    frames(cx);
+    super::type_in(&document, Some(1), None, cx);
+    document.update(cx, |document, cx| {
+        let open = document.open.as_ref().expect("a block is open");
+        open.input.update(cx, |input, cx| input.select(4..9, cx));
+    });
+    assert_eq!(
+        document.read_with(cx, |document, cx| document.selected(cx)),
+        "words"
+    );
+}