Add supertypes to grammar definition

corpus/expressions.txt

@@ -150,7 +150,7 @@ annotation_bind = 1 ^ 1::some_ann;
 ---
 
 (source_file
-  (assignment (identifier) (infix_operator (infix_operator (integer_literal) (integer_literal)) (integer_literal)))
+  (assignment (identifier) (infix_operator (parenthesised_expression (infix_operator (integer_literal) (integer_literal))) (integer_literal)))
   (assignment (identifier) (infix_operator (integer_literal) (infix_operator (integer_literal) (integer_literal))))
   (assignment (identifier) (infix_operator (integer_literal) (infix_operator (integer_literal) (integer_literal))))
   (assignment (identifier) (infix_operator (integer_literal) (infix_operator (integer_literal) (identifier)))))

grammar.js

@@ -29,6 +29,11 @@ module.exports = grammar({
     [$._expression, $.generator],
   ],
 
+  supertypes: $ => [
+    $._expression,
+    $._item,
+  ],
+
   rules: {
     source_file: $ => seq(sepBy(';', $._item)),
 
@@ -56,10 +61,11 @@ module.exports = grammar({
       $.prefix_operator,
       $.set_comprehension,
       $.string_interpolation,
-      // TODO: Other expression types
-      seq('(', $._expression, ')'),
+      $.parenthesised_expression,
     ),
 
+    parenthesised_expression: $ => seq('(', $._expression, ')'),
+
     array_comprehension: $ => seq(
       '[', $._expression, '|', sepBy1(',', $.generator), ']',
     ),

src/grammar.json

@@ -122,21 +122,25 @@
           "name": "string_interpolation"
         },
         {
-          "type": "SEQ",
-          "members": [
-            {
-              "type": "STRING",
-              "value": "("
-            },
-            {
-              "type": "SYMBOL",
-              "name": "_expression"
-            },
-            {
-              "type": "STRING",
-              "value": ")"
-            }
-          ]
+          "type": "SYMBOL",
+          "name": "parenthesised_expression"
+        }
+      ]
+    },
+    "parenthesised_expression": {
+      "type": "SEQ",
+      "members": [
+        {
+          "type": "STRING",
+          "value": "("
+        },
+        {
+          "type": "SYMBOL",
+          "name": "_expression"
+        },
+        {
+          "type": "STRING",
+          "value": ")"
         }
       ]
     },
@@ -1568,6 +1572,9 @@
   ],
   "externals": [],
   "inline": [],
-  "supertypes": []
+  "supertypes": [
+    "_expression",
+    "_item"
+  ]
 }