Support extension clause

Author: nicolasstucki

src/typescript/Scala.tmLanguage.ts

@@ -150,6 +150,9 @@ export const scalaTmLanguage: TmLanguage = {
         {
           include: '#inheritance'
         },
+        {
+          include: '#extension'
+        },
         {
           include: '#imports'
         },
@@ -859,6 +862,19 @@ export const scalaTmLanguage: TmLanguage = {
         }
       ]
     },
+    extension: {
+      patterns: [
+        {
+          match: `(extension)\\s+(?=[\\[\\(])`,
+          captures: {
+            '1': {
+              name: 'keyword.declaration.scala'
+            },
+
+          }
+        }
+      ]
+    },
     'parameter-list': {
       patterns: [
         {

tests/unit/extension.test.scala

@@ -0,0 +1,19 @@
+// SYNTAX TEST "source.scala"
+
+    extension (x: T) def combine (y: T): T
+//  ^^^^^^^^^ keyword.declaration.scala
+//             ^ variable.parameter.scala
+//              ^ meta.colon.scala
+//                ^ entity.name.class
+//                   ^^^ keyword.declaration.scala
+//                       ^^^^^^^ entity.name.function.declaration
+
+
+    extension [T](x: T) def combine (y: T): T
+//  ^^^^^^^^^ keyword.declaration.scala
+//             ^ entity.name.class
+//                ^ variable.parameter.scala
+//                 ^ meta.colon.scala
+//                   ^ entity.name.class
+//                      ^^^ keyword.declaration.scala
+//                          ^^^^^^^ entity.name.function.declaration