Allow structured binding declarators in pmore places

Refs atom/language-c#325

corpus/declarations.txt

@@ -656,27 +656,44 @@ auto [a] = B{};
 int main() {
   auto &&[b, c] = std::make_tuple(c);
   const auto [x, y] {1, 2};
+
+  for (const auto &[a, b] : c) {}
 }
 
 ---
 
 (translation_unit
-  (structured_binding_declaration (auto) (structured_binding_declarator (identifier)) (compound_literal_expression (type_identifier) (initializer_list)))
+  (declaration
+    (auto)
+    (init_declarator
+      (structured_binding_declarator (identifier))
+      (compound_literal_expression (type_identifier) (initializer_list))))
   (function_definition
     (primitive_type)
     (function_declarator (identifier) (parameter_list))
     (compound_statement
-      (structured_binding_declaration
+      (declaration
         (auto)
-        (reference_declarator (structured_binding_declarator (identifier) (identifier)))
+        (init_declarator
-        (call_expression
+          (reference_declarator (structured_binding_declarator (identifier) (identifier)))
-          (scoped_identifier (namespace_identifier) (identifier))
+          (call_expression
-          (argument_list (identifier))))
+            (scoped_identifier (namespace_identifier) (identifier))
-      (structured_binding_declaration
+            (argument_list (identifier)))))
+      (declaration
         (type_qualifier)
         (auto)
-        (structured_binding_declarator (identifier) (identifier))
+        (init_declarator
-        (initializer_list (number_literal) (number_literal))))))
+          (structured_binding_declarator (identifier) (identifier))
+          (initializer_list (number_literal) (number_literal))))
+      (for_range_loop
+        (for_range_declaration
+          (type_qualifier)
+          (auto)
+          (reference_declarator (structured_binding_declarator
+            (identifier)
+            (identifier))))
+          (identifier)
+          (compound_statement)))))
 
 ==========================
 Constexpr declarations

grammar.js

@@ -22,8 +22,9 @@ module.exports = grammar(C, {
     [$.scoped_type_identifier, $.scoped_field_identifier],
     [$.comma_expression, $.initializer_list],
     [$._type_specifier, $.optional_type_parameter_declaration],
-    [$._type_specifier, $._declarator, $._expression],
+    [$._expression, $._declarator],
-    [$._declarator, $._expression],
+    [$._expression, $.structured_binding_declarator],
+    [$._expression, $._declarator, $._type_specifier],
     [$.parameter_list, $.argument_list],
   ]),
 
@@ -40,7 +41,7 @@ module.exports = grammar(C, {
       $.alias_declaration,
       $.template_declaration,
       $.template_instantiation,
-      $.structured_binding_declaration,
+      // $.structured_binding_declaration,
       alias($.constructor_or_destructor_definition, $.function_definition)
     ),
 
@@ -149,19 +150,19 @@ module.exports = grammar(C, {
       original
     ),
 
-    structured_binding_declaration: $ => seq(
+    // structured_binding_declaration: $ => seq(
-      $._declaration_specifiers,
+    //   $._declaration_specifiers,
-      choice(
+    //   choice(
-        alias($.structured_binding_reference_declarator, $.reference_declarator),
+    //     alias($.structured_binding_reference_declarator, $.reference_declarator),
-        $.structured_binding_declarator,
+    //     $.structured_binding_declarator,
-      ),
+    //   ),
-      choice(
+    //   choice(
-        seq('=', choice($.initializer_list, $._expression)),
+    //     seq('=', choice($.initializer_list, $._expression)),
-        $.initializer_list,
+    //     $.initializer_list,
-        $.argument_list
+    //     $.argument_list
-      ),
+    //   ),
-      ';'
+    //   ';'
-    ),
+    // ),
 
     template_declaration: $ => seq(
       'template',
@@ -361,9 +362,16 @@ module.exports = grammar(C, {
       $.scoped_identifier,
       $.template_function,
       $.operator_name,
-      $.destructor_name
+      $.destructor_name,
+      $.structured_binding_declarator
     ),
 
+    // structured_declarator: $ => seq(
+    //   '[',
+    //   commaSep1($.identifier),
+    //   ']'
+    // ),
+
     _field_declarator: ($, original) => choice(
       original,
       alias($.reference_field_declarator, $.reference_declarator),
@@ -380,7 +388,7 @@ module.exports = grammar(C, {
     reference_field_declarator: $ => prec.dynamic(1, prec.right(seq(choice('&', '&&'), $._field_declarator))),
     abstract_reference_declarator: $ => prec.right(seq(choice('&', '&&'), optional($._abstract_declarator))),
 
-    structured_binding_reference_declarator: $ => seq(choice('&', '&&'), $.structured_binding_declarator),
+    // structured_binding_reference_declarator: $ => seq(choice('&', '&&'), $.structured_binding_declarator),
     structured_binding_declarator: $ => seq('[', commaSep1($.identifier), ']'),
 
     function_declarator: ($, original) => seq(

src/grammar.json

@@ -85,10 +85,6 @@
           "type": "SYMBOL",
           "name": "template_instantiation"
         },
-        {
-          "type": "SYMBOL",
-          "name": "structured_binding_declaration"
-        },
         {
           "type": "ALIAS",
           "content": {
@@ -1022,6 +1018,10 @@
         {
           "type": "SYMBOL",
           "name": "destructor_name"
+        },
+        {
+          "type": "SYMBOL",
+          "name": "structured_binding_declarator"
         }
       ]
     },
@@ -5316,72 +5316,6 @@
         ]
       }
     },
-    "structured_binding_declaration": {
-      "type": "SEQ",
-      "members": [
-        {
-          "type": "SYMBOL",
-          "name": "_declaration_specifiers"
-        },
-        {
-          "type": "CHOICE",
-          "members": [
-            {
-              "type": "ALIAS",
-              "content": {
-                "type": "SYMBOL",
-                "name": "structured_binding_reference_declarator"
-              },
-              "named": true,
-              "value": "reference_declarator"
-            },
-            {
-              "type": "SYMBOL",
-              "name": "structured_binding_declarator"
-            }
-          ]
-        },
-        {
-          "type": "CHOICE",
-          "members": [
-            {
-              "type": "SEQ",
-              "members": [
-                {
-                  "type": "STRING",
-                  "value": "="
-                },
-                {
-                  "type": "CHOICE",
-                  "members": [
-                    {
-                      "type": "SYMBOL",
-                      "name": "initializer_list"
-                    },
-                    {
-                      "type": "SYMBOL",
-                      "name": "_expression"
-                    }
-                  ]
-                }
-              ]
-            },
-            {
-              "type": "SYMBOL",
-              "name": "initializer_list"
-            },
-            {
-              "type": "SYMBOL",
-              "name": "argument_list"
-            }
-          ]
-        },
-        {
-          "type": "STRING",
-          "value": ";"
-        }
-      ]
-    },
     "template_declaration": {
       "type": "SEQ",
       "members": [
@@ -6088,28 +6022,6 @@
         ]
       }
     },
-    "structured_binding_reference_declarator": {
-      "type": "SEQ",
-      "members": [
-        {
-          "type": "CHOICE",
-          "members": [
-            {
-              "type": "STRING",
-              "value": "&"
-            },
-            {
-              "type": "STRING",
-              "value": "&&"
-            }
-          ]
-        },
-        {
-          "type": "SYMBOL",
-          "name": "structured_binding_declarator"
-        }
-      ]
-    },
     "structured_binding_declarator": {
       "type": "SEQ",
       "members": [
@@ -7239,13 +7151,17 @@
       "optional_type_parameter_declaration"
     ],
     [
-      "_type_specifier",
+      "_expression",
-      "_declarator",
+      "_declarator"
-      "_expression"
+    ],
+    [
+      "_expression",
+      "structured_binding_declarator"
     ],
     [
+      "_expression",
       "_declarator",
-      "_expression"
+      "_type_specifier"
     ],
     [
       "parameter_list",