Reuse LHS classes for "augmented_assignment_expression" (#146)

* designate special group for LHS of augmented assignment expression

needed for tree-sitter/tree-sitter-typescript#119

* regenerate parser for '_augmented_assignment_lhs'

Co-authored-by: resolritter <[email protected]>

Author: resolritter

grammar.js

@@ -698,14 +698,16 @@ module.exports = grammar({
       field('right', $._expression)
     )),
 
+    _augmented_assignment_lhs: $ => choice(
+      $.member_expression,
+      $.subscript_expression,
+      alias($._reserved_identifier, $.identifier),
+      $.identifier,
+      $.parenthesized_expression,
+    ),
+
     augmented_assignment_expression: $ => prec.right(PREC.ASSIGN, seq(
-      field('left', choice(
-        $.member_expression,
-        $.subscript_expression,
-        alias($._reserved_identifier, $.identifier),
-        $.identifier,
-        $.parenthesized_expression,
-      )),
+      field('left', $._augmented_assignment_lhs),
       choice('+=', '-=', '*=', '/=', '%=', '^=', '&=', '|=', '>>=', '>>>=',
              '<<=', '**=', '&&=', '||=', '??='),
       field('right', $._expression)

src/grammar.json

@@ -3088,6 +3088,36 @@
         ]
       }
     },
+    "_augmented_assignment_lhs": {
+      "type": "CHOICE",
+      "members": [
+        {
+          "type": "SYMBOL",
+          "name": "member_expression"
+        },
+        {
+          "type": "SYMBOL",
+          "name": "subscript_expression"
+        },
+        {
+          "type": "ALIAS",
+          "content": {
+            "type": "SYMBOL",
+            "name": "_reserved_identifier"
+          },
+          "named": true,
+          "value": "identifier"
+        },
+        {
+          "type": "SYMBOL",
+          "name": "identifier"
+        },
+        {
+          "type": "SYMBOL",
+          "name": "parenthesized_expression"
+        }
+      ]
+    },
     "augmented_assignment_expression": {
       "type": "PREC_RIGHT",
       "value": 0,
@@ -3098,34 +3128,8 @@
             "type": "FIELD",
             "name": "left",
             "content": {
-              "type": "CHOICE",
-              "members": [
-                {
-                  "type": "SYMBOL",
-                  "name": "member_expression"
-                },
-                {
-                  "type": "SYMBOL",
-                  "name": "subscript_expression"
-                },
-                {
-                  "type": "ALIAS",
-                  "content": {
-                    "type": "SYMBOL",
-                    "name": "_reserved_identifier"
-                  },
-                  "named": true,
-                  "value": "identifier"
-                },
-                {
-                  "type": "SYMBOL",
-                  "name": "identifier"
-                },
-                {
-                  "type": "SYMBOL",
-                  "name": "parenthesized_expression"
-                }
-              ]
+              "type": "SYMBOL",
+              "name": "_augmented_assignment_lhs"
             }
           },
           {