Add Scala support

README.md

@@ -73,6 +73,7 @@ Difftastic supports the following languages:
 * Python
 * Ruby
 * Rust
+* Scala
 * TypeScript (and TSX)
 
 If a file has an unrecognised extension, difftastic uses a

build.rs

@@ -149,6 +149,11 @@ fn main() {
             src_dir: "vendor/tree-sitter-rust-src",
             extra_files: vec!["scanner.c"],
         },
+        TreeSitterParser {
+            name: "tree-sitter-scala",
+            src_dir: "vendor/tree-sitter-scala-src",
+            extra_files: vec!["scanner.c"],
+        },
         TreeSitterParser {
             name: "tree-sitter-tsx",
             src_dir: "vendor/tree-sitter-typescript-src/tsx/src",

sample_files/scala_after.scala

@@ -0,0 +1,21 @@
+package foo
+
+import foo.Baz
+
+class Foo {
+
+  private def blah(): Other {
+    throw new Exception("after");
+  }
+
+  var result = Option.empty[T]
+  val fn = pf.lift
+  object traverser extends SimpleTraverser {
+    override def apply(t: Tree): Unit = {
+      result = fn(t).orElse(result)
+      if (result.nonEmpty) {
+        super.apply(t)
+      }
+    }
+  }
+}

sample_files/scala_before.scala

@@ -0,0 +1,21 @@
+package foo
+
+import foo.Bar
+
+class Foo {
+
+  def blah(): Int {
+    throw new Exception("before");
+  }
+
+  var result = Option.empty[T]                      
+  object traverser extends SimpleTraverser {
+    override def apply(t: Tree): Unit = {
+      if (result.isEmpty && pf.isDefinedAt(t)) {
+        result = Some(pf(t))
+      } else if (result.isEmpty) {
+        super.apply(t)
+      }
+    }
+  }
+}

src/guess_language.rs

@@ -38,6 +38,7 @@ pub enum Language {
     Python,
     Ruby,
     Rust,
+    Scala,
     Tsx,
     TypeScript,
 }
@@ -139,6 +140,7 @@ fn from_extension(extension: &OsStr) -> Option<Language> {
         "py" | "py3" | "pyi" | "bzl" => Some(Python),
         "rb" | "builder" | "spec" | "rake" => Some(Ruby),
         "rs" => Some(Rust),
+        "scala" | "sbt" | "sc" => Some(Scala),
         "ts" => Some(TypeScript),
         "tsx" => Some(Tsx),
         _ => None,

src/tree_sitter_parser.rs

@@ -62,6 +62,7 @@ extern "C" {
     fn tree_sitter_python() -> ts::Language;
     fn tree_sitter_ruby() -> ts::Language;
     fn tree_sitter_rust() -> ts::Language;
+    fn tree_sitter_scala() -> ts::Language;
     fn tree_sitter_tsx() -> ts::Language;
     fn tree_sitter_typescript() -> ts::Language;
 }
@@ -379,6 +380,16 @@ pub fn from_language(language: guess::Language) -> TreeSitterConfig {
                 .unwrap(),
             }
         }
+        Scala => {
+            let language = unsafe { tree_sitter_scala() };
+            TreeSitterConfig {
+                name: "Rust",
+                language: unsafe { tree_sitter_scala() },
+                atom_nodes: (vec!["string", "template_string"]).into_iter().collect(),
+                delimiter_tokens: (vec![("{", "}"), ("(", ")"), ("[", "]")]),
+                highlight_query: ts::Query::new(language, "").unwrap(),
+            }
+        }
         TypeScript => {
             let language = unsafe { tree_sitter_typescript() };
             TreeSitterConfig {

vendor/tree-sitter-scala-src

@@ -0,0 +1 @@
+tree-sitter-scala/src