fix: Only allow structured events, not scalar ones (#51)

For #17

Author: bugwelle

CHANGELOG.md

@@ -15,6 +15,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Changed
 
 - Updated to tree-sitter v0.22.6
+- grammar:
+  + Only structured events (+ projections) are allowed, not scalar ones.
 
 ### Fixed
 

grammar.js

@@ -171,19 +171,13 @@ module.exports = grammar({
         seq($.element_definitions, optional(';')),
         seq(':',
           choice(
-            seq(
-              $.simple_path,
-              choice(
-                seq(
-                  repeat(seq(',', $.simple_path)),
-                  $.element_definitions,
-                  optional(';'),
-                ),
-                seq(repeat($.annotation), $._required_semicolon),
-              ),
-            ),
             seq($.element_definitions, optional(';')),
             seq($.projection_clause, $._required_semicolon),
+            seq(
+              field('includes', optional_list_of_trailing($.simple_path)),
+              $.element_definitions,
+              optional(';'),
+            ),
           ),
         ),
       ),