Merge pull request #93 from ninevra/dispatch-on-well-known-attrs

Generalize attribute syntax

corpus/declarations.txt

@@ -176,13 +176,13 @@ fn accumulate(self) -> Machine<{State::Accumulate}> {}
     name: (identifier)
     parameters: (parameters
       (attribute_item
-        (meta_item
+        (attr_item
           (identifier)))
       (parameter
         pattern: (identifier)
         type: (primitive_type))
       (attribute_item
-        (meta_item
+        (attr_item
           (identifier)))
       (parameter
         pattern: (identifier)
@@ -473,7 +473,7 @@ struct Inches(i32);
         (field_identifier)
         (primitive_type))
       (attribute_item
-        (meta_item
+        (attr_item
           (identifier)))
       (field_declaration
         (field_identifier)
@@ -632,10 +632,10 @@ pub enum Node<T: Item> {
             (field_identifier)
             (primitive_type))))
       (attribute_item
-        (meta_item
+        (attr_item
           (identifier)))
       (attribute_item
-        (meta_item
+        (attr_item
           (identifier)))
       (enum_variant
         (identifier)
@@ -968,7 +968,7 @@ mod macos_only {}
             path: (identifier)
             name: (identifier))))))
   (attribute_item
-    (meta_item
+    (attr_item
       (scoped_identifier
         path: (identifier)
         name: (identifier))
@@ -996,6 +996,131 @@ mod macos_only {
               (identifier)
               value: (string_literal))))))))
 
+================================================================================
+Key-Value Attribute Expressions
+================================================================================
+
+#[doc = include_str!("foo-doc.md")]
+fn foo() {}
+
+#[namespace = foo::bar]
+fn baz() {}
+
+--------------------------------------------------------------------------------
+
+(source_file
+  (attribute_item
+    (meta_item
+      (identifier)
+      (macro_invocation
+        (identifier)
+        (token_tree
+          (string_literal)))))
+  (function_item
+    (identifier)
+    (parameters)
+    (block))
+  (attribute_item
+    (attr_item
+      (identifier)
+      (scoped_identifier
+        (identifier)
+        (identifier))))
+  (function_item
+    (identifier)
+    (parameters)
+    (block)))
+
+================================================================================
+Attribute macros
+================================================================================
+
+foo(#[attr(=> arbitrary tokens <=)] x, y);
+
+foo(#[bar(some tokens are special in other contexts: $/';()*()+.)] x);
+
+--------------------------------------------------------------------------------
+
+(source_file
+  (expression_statement
+    (call_expression
+      function: (identifier)
+      arguments: (arguments
+        (attribute_item (attr_item
+          (identifier)
+          arguments: (token_tree (identifier) (identifier))))
+        (identifier)
+        (identifier))))
+  (expression_statement
+    (call_expression
+      function: (identifier)
+      arguments: (arguments
+        (attribute_item (attr_item
+          (identifier)
+          arguments: (token_tree
+            (identifier)
+            (identifier)
+            (identifier)
+            (identifier)
+            (identifier)
+            (identifier)
+            (identifier)
+            (token_tree)
+            (token_tree))))
+        (identifier)))))
+
+================================================================================
+Derive macro helper attributes
+================================================================================
+
+// Example from https://github.com/dtolnay/thiserror/blob/21c26903e29cb92ba1a7ff11e82ae2001646b60d/README.md
+
+use thiserror::Error;
+
+#[derive(Error, Debug)]
+pub enum Error {
+    #[error("first letter must be lowercase but was {:?}", first_char(.0))]
+    WrongCase(String),
+    #[error("invalid index {idx}, expected at least {} and at most {}", .limits.lo, .limits.hi)]
+    OutOfBounds { idx: usize, limits: Limits },
+}
+
+--------------------------------------------------------------------------------
+
+(source_file
+  (line_comment)
+  (use_declaration
+    (scoped_identifier (identifier) (identifier)))
+  (attribute_item
+    (meta_item (identifier)
+      (meta_arguments
+        (meta_item (identifier))
+        (meta_item (identifier)))))
+  (enum_item
+    (visibility_modifier)
+    (type_identifier)
+    (enum_variant_list
+      (attribute_item (attr_item
+        (identifier)
+        (token_tree
+          (string_literal)
+          (identifier)
+          (token_tree (integer_literal)))))
+      (enum_variant (identifier)
+        (ordered_field_declaration_list (type_identifier)))
+      (attribute_item (attr_item
+        (identifier)
+        (token_tree
+          (string_literal)
+          (identifier)
+          (identifier)
+          (identifier)
+          (identifier))))
+      (enum_variant (identifier)
+        (field_declaration_list
+          (field_declaration (field_identifier) (primitive_type))
+          (field_declaration (field_identifier) (type_identifier)))))))
+
 ================================================================================
 Attributes and Expressions
 ================================================================================
@@ -1032,7 +1157,7 @@ fn foo() {
         pattern: (identifier)
         value: (array_expression
           (attribute_item
-            (meta_item
+            (attr_item
               (identifier)))
           (integer_literal)
           (integer_literal)
@@ -1041,7 +1166,7 @@ fn foo() {
         pattern: (identifier)
         value: (tuple_expression
           (attribute_item
-            (meta_item
+            (attr_item
               (identifier)))
           (integer_literal)
           (integer_literal)

corpus/expressions.txt

@@ -607,7 +607,7 @@ let msg = match x {
           value: (integer_literal))
         (match_arm
           (attribute_item
-            (meta_item
+            (attr_item
               (identifier)))
           pattern: (match_pattern
             (integer_literal))

grammar.js

@@ -35,6 +35,54 @@ const numeric_types = [
 
 const primitive_types = numeric_types.concat(['bool', 'str', 'char'])
 
+const built_in_attributes = [
+  'cfg',
+  'cfg_attr',
+  'test',
+  'ignore',
+  'should_panic',
+  'derive',
+  'automatically_derived',
+  'macro_export',
+  'macro_use',
+  'proc_macro',
+  'proc_macro_derive',
+  'proc_macro_attribute',
+  'allow',
+  'warn',
+  'deny',
+  'forbid',
+  'deprecated',
+  'must_use',
+  'link',
+  'link_name',
+  'no_link',
+  'repr',
+  'crate_type',
+  'no_main',
+  'export_name',
+  'link_section',
+  'no_mangle',
+  'used',
+  'crate_name',
+  'inline',
+  'cold',
+  'no_builtins',
+  'target_feature',
+  'track_caller',
+  'doc',
+  'no_std',
+  'no_implicit_prelude',
+  'path',
+  'recursion_limit',
+  'type_length_limit',
+  'panic_handler',
+  'global_allocator',
+  'windows_subsystem',
+  'feature',
+  'non_exhaustive'
+]
+
 module.exports = grammar({
   name: 'rust',
 
@@ -210,22 +258,47 @@ module.exports = grammar({
     attribute_item: $ => seq(
       '#',
       '[',
-      $.meta_item,
+      $._attr,
       ']'
     ),
 
     inner_attribute_item: $ => seq(
       '#',
       '!',
       '[',
-      $.meta_item,
+      $._attr,
       ']'
     ),
 
+    _attr: $ => choice(
+      alias($.built_in_attr, $.meta_item),
+      alias($.custom_attr, $.attr_item),
+    ),
+
+    custom_attr: $ => seq(
+      $._path,
+      optional(choice(
+        seq('=', field('value', $._expression)),
+        field('arguments', alias($.delim_token_tree, $.token_tree))
+      ))
+    ),
+
+    built_in_attr: $ => seq(
+      $._built_in_attr_path,
+      optional(choice(
+        seq('=', field('value', $._expression)),
+        field('arguments', $.meta_arguments)
+      ))
+    ),
+
+    _built_in_attr_path: $ => choice(
+      ...built_in_attributes.map(name => alias(name, $.identifier))
+    ),
+
     meta_item: $ => seq(
       $._path,
       optional(choice(
-        seq('=', field('value', $._literal)),
+        seq('=', field('value', $._expression)),
         field('arguments', $.meta_arguments)
       ))
     ),