feat: resources can implement interfaces

examples/tests/invalid/impl_interface.w

@@ -0,0 +1,14 @@
+bring cloud;
+
+resource A impl cloud.IQueueOnMessageHandler {
+  // Error: A does not implement "handle" method of cloud.IQueueOnMessageHandler
+  init() {}
+}
+
+resource B impl cloud.IQueueOnMessageHandler {
+  init() {}
+  inflight handle() {
+    // Error: Expected type to be "inflight (str): void", but got "inflight (): void" instead
+    return;
+  }
+}

examples/tests/valid/impl_interface.w

@@ -0,0 +1,15 @@
+bring cloud;
+
+resource A impl cloud.IQueueOnMessageHandler {
+  init() {}
+  inflight handle(msg: str) {
+    return;
+  }
+}
+
+resource B impl cloud.IQueueOnMessageHandler {
+  init() {}
+  inflight handle(msg: str): num { // its okay to return a more specific type
+    return 5;
+  }
+}

libs/tree-sitter-wing/grammar.js

@@ -74,6 +74,7 @@ module.exports = grammar({
         $.return_statement,
         $.class_definition,
         $.resource_definition,
+        $.interface_definition,
         $.for_in_loop,
         $.while_statement,
         $.if_statement,
@@ -143,6 +144,7 @@ module.exports = grammar({
         "class",
         field("name", $.identifier),
         optional(seq("extends", field("parent", $.custom_type))),
+        optional(seq("impl", field("implements", commaSep1($.custom_type)))),
         field("implementation", $.class_implementation)
       ),
     class_implementation: ($) =>
@@ -175,6 +177,7 @@ module.exports = grammar({
         "resource",
         field("name", $.identifier),
         optional(seq("extends", field("parent", $.custom_type))),
+        optional(seq("impl", field("implements", commaSep1($.custom_type)))),
         field("implementation", $.resource_implementation)
       ),
     resource_implementation: ($) =>
@@ -191,6 +194,26 @@ module.exports = grammar({
         "}"
       ),
 
+    interface_definition: ($) =>
+      seq(
+        "interface",
+        field("name", $.identifier),
+        optional(seq("extends", field("implements", commaSep1($.custom_type)))),
+        field("implementation", $.interface_implementation)
+      ),
+    interface_implementation: ($) =>
+      seq(
+        "{",
+        repeat(
+          choice(
+            $.method_signature,
+            $.inflight_method_signature,
+            $.class_field,
+          )
+        ),
+        "}"
+      ),
+
     for_in_loop: ($) =>
       seq(
         "for",
@@ -370,6 +393,17 @@ module.exports = grammar({
         field("block", $.block)
       ),
 
+    method_signature: ($) =>
+      seq(
+        optional(field("access_modifier", $.access_modifier)),
+        optional(field("static", $.static)),
+        optional(field("async", $.async_modifier)),
+        field("name", $.identifier),
+        field("parameter_list", $.parameter_list),
+        optional(field("return_type", $._type_annotation)),
+        ";"
+      ),
+
     method_definition: ($) =>
       seq(
         optional(field("access_modifier", $.access_modifier)),
@@ -381,6 +415,17 @@ module.exports = grammar({
         field("block", $.block)
       ),
 
+    inflight_method_signature: ($) =>
+      seq(
+        optional(field("access_modifier", $.access_modifier)),
+        optional(field("static", $.static)),
+        field("phase_modifier", $._inflight_specifier),
+        field("name", $.identifier),
+        field("parameter_list", $.parameter_list),
+        optional(field("return_type", $._type_annotation)),
+        ";"
+      ),
+
     inflight_method_definition: ($) =>
       seq(
         optional(field("access_modifier", $.access_modifier)),

libs/tree-sitter-wing/project.json

@@ -3,6 +3,7 @@
   "$schema": "../../node_modules/nx/schemas/project-schema.json",
   "targets": {
     "test": {
+      "dependsOn": ["build"],
       "executor": "nx:run-commands",
       "options": {
         "command": "npm run test",