Handle __attribute__ in function declaration (#19)

* Handle __attribute__ in function declaration

* Fix tests in examples/

* Remove useless optional

corpus/declarations.txt

@@ -362,3 +362,41 @@ int main() {
     (compound_statement
       (declaration (primitive_type) (array_declarator (identifier) (identifier)))
       (declaration (primitive_type) (array_declarator (identifier))))))
+
+================================
+Attributes
+================================
+
+extern __attribute__((visibility("hidden"))) int foo();
+extern int bar() __attribute__((const));
+void die(const char *format, ...) __attribute__((noreturn))
+                                  __attribute__((format(printf,1,2)));
+extern __attribute__((visibility("default"), weak)) int print_status();
+
+---
+
+(translation_unit
+  (declaration
+    (storage_class_specifier)
+    (attribute_specifier
+      (argument_list
+        (call_expression
+          (identifier) (argument_list (string_literal)))))
+    (primitive_type)
+    (function_declarator (identifier) (parameter_list)))
+  (declaration
+    (storage_class_specifier)
+    (primitive_type)
+    (function_declarator (identifier) (parameter_list) (attribute_specifier (argument_list (identifier)))))
+  (declaration
+    (primitive_type)
+    (function_declarator (identifier)
+      (parameter_list (parameter_declaration (type_qualifier) (primitive_type) (pointer_declarator (identifier))))
+      (attribute_specifier (argument_list (identifier)))
+      (attribute_specifier
+        (argument_list (call_expression (identifier) (argument_list (identifier) (number_literal) (number_literal)))))))
+  (declaration
+    (storage_class_specifier)
+    (attribute_specifier
+      (argument_list (call_expression (identifier) (argument_list (string_literal))) (identifier)))
+    (primitive_type) (function_declarator (identifier) (parameter_list))))

grammar.js

@@ -132,12 +132,14 @@ module.exports = grammar({
     _declaration_specifiers: $ => seq(
       repeat(choice(
         $.storage_class_specifier,
-        $.type_qualifier
+        $.type_qualifier,
+        $.attribute_specifier
       )),
       $._type_specifier,
       repeat(choice(
         $.storage_class_specifier,
-        $.type_qualifier
+        $.type_qualifier,
+        $.attribute_specifier
       ))
     ),
 
@@ -151,6 +153,15 @@ module.exports = grammar({
       )
     ),
 
+    attribute_specifier: $ => seq(
+      '__attribute__',
+      seq(
+        '(',
+        $.argument_list,
+        ')'
+      )
+    ),
+
     declaration_list: $ => seq(
       '{',
       repeat($._top_level_item),
@@ -193,7 +204,7 @@ module.exports = grammar({
     pointer_type_declarator: $ => prec.dynamic(1, prec.right(seq('*', repeat($.type_qualifier), $._type_declarator))),
     abstract_pointer_declarator: $ => prec.dynamic(1, prec.right(seq('*', repeat($.type_qualifier), optional($._abstract_declarator)))),
 
-    function_declarator: $ => prec(1, seq($._declarator, $.parameter_list)),
+    function_declarator: $ => prec(1, seq($._declarator, $.parameter_list, repeat($.attribute_specifier))),
     function_field_declarator: $ => prec(1, seq($._field_declarator, $.parameter_list)),
     function_type_declarator: $ => prec(1, seq($._type_declarator, $.parameter_list)),
     abstract_function_declarator: $ => prec(1, seq(optional($._abstract_declarator), $.parameter_list)),

src/grammar.json

@@ -820,6 +820,10 @@
               {
                 "type": "SYMBOL",
                 "name": "type_qualifier"
+              },
+              {
+                "type": "SYMBOL",
+                "name": "attribute_specifier"
               }
             ]
           }
@@ -840,6 +844,10 @@
               {
                 "type": "SYMBOL",
                 "name": "type_qualifier"
+              },
+              {
+                "type": "SYMBOL",
+                "name": "attribute_specifier"
               }
             ]
           }
@@ -876,6 +884,32 @@
         }
       ]
     },
+    "attribute_specifier": {
+      "type": "SEQ",
+      "members": [
+        {
+          "type": "STRING",
+          "value": "__attribute__"
+        },
+        {
+          "type": "SEQ",
+          "members": [
+            {
+              "type": "STRING",
+              "value": "("
+            },
+            {
+              "type": "SYMBOL",
+              "name": "argument_list"
+            },
+            {
+              "type": "STRING",
+              "value": ")"
+            }
+          ]
+        }
+      ]
+    },
     "declaration_list": {
       "type": "SEQ",
       "members": [
@@ -1223,6 +1257,13 @@
           {
             "type": "SYMBOL",
             "name": "parameter_list"
+          },
+          {
+            "type": "REPEAT",
+            "content": {
+              "type": "SYMBOL",
+              "name": "attribute_specifier"
+            }
           }
         ]
       }