Add basic support for ruby

Co-authored-by: Kay Simmons <kay@zed.dev>

crates/language/src/buffer.rs

@@ -1764,6 +1764,7 @@ impl BufferSnapshot {
             .collect::<Vec<_>>();
 
         let mut indent_ranges = Vec::<Range<Point>>::new();
+        let mut outdent_positions = Vec::<Point>::new();
         while let Some(mat) = matches.peek() {
             let mut start: Option<Point> = None;
             let mut end: Option<Point> = None;
@@ -1777,6 +1778,8 @@ impl BufferSnapshot {
                     start = Some(Point::from_ts_point(capture.node.end_position()));
                 } else if Some(capture.index) == config.end_capture_ix {
                     end = Some(Point::from_ts_point(capture.node.start_position()));
+                } else if Some(capture.index) == config.outdent_capture_ix {
+                    outdent_positions.push(Point::from_ts_point(capture.node.start_position()));
                 }
             }
 
@@ -1797,6 +1800,19 @@ impl BufferSnapshot {
             }
         }
 
+        outdent_positions.sort();
+        for outdent_position in outdent_positions {
+            // find the innermost indent range containing this outdent_position
+            // set its end to the outdent position
+            if let Some(range_to_truncate) = indent_ranges
+                .iter_mut()
+                .filter(|indent_range| indent_range.contains(&outdent_position))
+                .last()
+            {
+                range_to_truncate.end = outdent_position;
+            }
+        }
+
         // Find the suggested indentation increases and decreased based on regexes.
         let mut indent_change_rows = Vec::<(u32, Ordering)>::new();
         self.for_each_line(

crates/language/src/buffer_tests.rs

@@ -1150,6 +1150,49 @@ fn test_autoindent_with_injected_languages(cx: &mut MutableAppContext) {
     });
 }
 
+#[gpui::test]
+fn test_autoindent_query_with_outdent_captures(cx: &mut MutableAppContext) {
+    let mut settings = Settings::test(cx);
+    settings.editor_defaults.tab_size = Some(2.try_into().unwrap());
+    cx.set_global(settings);
+    cx.add_model(|cx| {
+        let mut buffer = Buffer::new(0, "", cx).with_language(Arc::new(ruby_lang()), cx);
+
+        let text = r#"
+            class C
+            def a(b, c)
+            puts b
+            puts c
+            rescue
+            puts "errored"
+            exit 1
+            end
+            end
+        "#
+        .unindent();
+
+        buffer.edit([(0..0, text)], Some(AutoindentMode::EachLine), cx);
+
+        assert_eq!(
+            buffer.text(),
+            r#"
+                class C
+                  def a(b, c)
+                    puts b
+                    puts c
+                  rescue
+                    puts "errored"
+                    exit 1
+                  end
+                end
+            "#
+            .unindent()
+        );
+
+        buffer
+    });
+}
+
 #[gpui::test]
 fn test_serialization(cx: &mut gpui::MutableAppContext) {
     let mut now = Instant::now();
@@ -1497,6 +1540,26 @@ impl Buffer {
     }
 }
 
+fn ruby_lang() -> Language {
+    Language::new(
+        LanguageConfig {
+            name: "Ruby".into(),
+            path_suffixes: vec!["rb".to_string()],
+            ..Default::default()
+        },
+        Some(tree_sitter_ruby::language()),
+    )
+    .with_indents_query(
+        r#"
+            (class "end" @end) @indent
+            (method "end" @end) @indent
+            (rescue) @outdent
+            (then) @indent
+        "#,
+    )
+    .unwrap()
+}
+
 fn rust_lang() -> Language {
     Language::new(
         LanguageConfig {

crates/language/src/language.rs

@@ -312,6 +312,7 @@ struct IndentConfig {
     indent_capture_ix: u32,
     start_capture_ix: Option<u32>,
     end_capture_ix: Option<u32>,
+    outdent_capture_ix: Option<u32>,
 }
 
 struct OutlineConfig {
@@ -670,12 +671,14 @@ impl Language {
         let mut indent_capture_ix = None;
         let mut start_capture_ix = None;
         let mut end_capture_ix = None;
+        let mut outdent_capture_ix = None;
         get_capture_indices(
             &query,
             &mut [
                 ("indent", &mut indent_capture_ix),
                 ("start", &mut start_capture_ix),
                 ("end", &mut end_capture_ix),
+                ("outdent", &mut outdent_capture_ix),
             ],
         );
         if let Some(indent_capture_ix) = indent_capture_ix {
@@ -684,6 +687,7 @@ impl Language {
                 indent_capture_ix,
                 start_capture_ix,
                 end_capture_ix,
+                outdent_capture_ix,
             });
         }
         Ok(self)