Parse attribute syntax

grammar.js

@@ -35,15 +35,18 @@ module.exports = grammar({
         $.external_function,
         $.function,
         $.type_definition,
-        $.type_alias
+        $.type_alias,
+        $.attribute
       ),
 
     /* Comments */
     module_comment: ($) => token(seq("////", /.*/)),
     statement_comment: ($) => token(seq("///", /.*/)),
     comment: ($) => token(seq("//", /.*/)),
 
-    /* Target groups */
+    /* Target groups
+     * DEPRECATED: This syntax was replaced with attributes in v0.30.
+     */
     target_group: ($) =>
       seq(
         "if",
@@ -54,6 +57,23 @@ module.exports = grammar({
       ),
     target: ($) => choice("erlang", "javascript"),
 
+    /* Attributes */
+    attribute: ($) =>
+      seq(
+        "@",
+        field("name", $.identifier),
+        field("arguments", alias($._attribute_arguments, $.arguments))
+      ),
+
+    _attribute_arguments: ($) =>
+      seq("(", series_of($.attribute_value, ","), ")"),
+
+    attribute_value: ($) =>
+      choice(
+        $._constant_value,
+        seq(field("label", $.label), ":", field("value", $._constant_value))
+      ),
+
     /* Import statements */
     import: ($) =>
       seq(

queries/highlights.scm

@@ -43,6 +43,13 @@
 (tuple_access
   index: (integer) @property)
 
+; Attributes
+(attribute
+  "@" @attribute
+  name: (identifier) @attribute)
+
+(attribute_value (identifier) @constant)
+
 ; Type names
 (remote_type_identifier) @type
 (type_identifier) @type

test/corpus/attributes.txt

@@ -0,0 +1,48 @@
+================================================================================
+Target attribute
+================================================================================
+
+@target(erlang)
+pub fn main() { todo }
+
+--------------------------------------------------------------------------------
+
+(source_file
+  (attribute
+    name: (identifier)
+    arguments: (arguments
+      (attribute_value
+        (identifier))))
+  (function
+    (visibility_modifier)
+    name: (identifier)
+    parameters: (function_parameters)
+    body: (function_body
+      (todo))))
+
+================================================================================
+Attribute with multiple values
+================================================================================
+
+@deprecated(since: "1.2.0", replacement: wobble)
+pub fn wibble() { todo }
+
+--------------------------------------------------------------------------------
+
+(source_file
+  (attribute
+    name: (identifier)
+    arguments: (arguments
+      (attribute_value
+        label: (label)
+        value: (string
+          (quoted_content)))
+      (attribute_value
+        label: (label)
+        value: (identifier))))
+  (function
+    (visibility_modifier)
+    name: (identifier)
+    parameters: (function_parameters)
+    body: (function_body
+      (todo))))

test/highlight/modules.gleam

@@ -48,3 +48,27 @@ fn make_cat() -> kitty.Cat {
   // ^ module
   //    ^ constructor
 }
+
+@target(erlang)
+// <- attribute
+// ^ attribute
+//        ^ constant
+pub external fn display() -> Bool = "erlang" "display"
+
+@target(erlang)
+@external(erlang, "wobble", "main")
+// <- attribute
+// ^ attribute
+//         ^ constant
+//                   ^ string
+//                            string
+pub fn main() -> Int
+
+@deprecated(since: "1.2.0", replacement: wobble)
+// <- attribute
+// ^ attribute
+//           ^ property
+//                  ^ string
+//                            ^ property
+//                                        ^constant
+pub fn wibble() { todo }