Fixes and fixes

grammar.js

@@ -154,7 +154,7 @@ module.exports = grammar({
     c_style_for_statement: $ => seq(
       'for',
       '((',
-      choice($._for_body, ';;'),
+      choice($._for_body),
       '))',
       optional(';'),
       field('body', choice(
@@ -164,9 +164,9 @@ module.exports = grammar({
     ),
     _for_body: $ => seq(
       field('initializer', commaSep($._c_expression)),
-      $._terminator,
+      $._c_terminator,
       field('condition', commaSep($._c_expression)),
-      $._terminator,
+      $._c_terminator,
       field('update', commaSep($._c_expression)),
     ),
 
@@ -184,6 +184,7 @@ module.exports = grammar({
       alias($._c_binary_expression, $.binary_expression),
       alias($._c_postfix_expression, $.postfix_expression),
       alias($._c_parenthesized_expression, $.parenthesized_expression),
+      $.command_substitution,
     ),
 
     _c_variable_assignment: $ => seq(
@@ -196,7 +197,7 @@ module.exports = grammar({
       $._c_expression_not_assignment,
     )),
     _c_binary_expression: $ => prec.right(seq(
-      choice($._c_word, $.simple_expansion),
+      $._c_expression_not_assignment,
       choice(
         '+=', '-=', '*=', '/=', '%=', '**=',
         '<<=', '>>=', '&=', '^=', '|=',
@@ -213,7 +214,7 @@ module.exports = grammar({
     ),
     _c_parenthesized_expression: $ => seq(
       '(',
-      $._c_expression,
+      commaSep1($._c_expression),
       ')',
     ),
     _c_word: $ => alias(/[a-zA-Z_][a-zA-Z0-9_]*/, $.word),
@@ -314,7 +315,7 @@ module.exports = grammar({
 
     compound_statement: $ => seq(
       '{',
-      optional(choice($._statements2, seq($._statement, optional($._terminator)))),
+      optional(choice($._statements2, seq($._statement, $._terminator))),
       alias(token(prec(-1, '}')), '}'),
     ),
 
@@ -352,7 +353,7 @@ module.exports = grammar({
       choice(
         seq('[', choice($._expression, $.redirected_statement), ']'),
         seq('[[', $._expression, ']]'),
-        seq('(', '(', $._expression, '))'),
+        seq('(', '(', optional($._expression), '))'),
       ),
     ),
 
@@ -541,7 +542,76 @@ module.exports = grammar({
       $.arithmetic_expansion,
     ),
 
-    arithmetic_expansion: $ => seq('$(', '(', $._expression, '))'),
+    arithmetic_expansion: $ => seq('$((', $._arithmetic_expression, '))'),
+
+    _arithmetic_expression: $ => choice(
+      $._arithmetic_literal,
+      alias($._arithmetic_unary_expression, $.unary_expression),
+      alias($._arithmetic_ternary_expression, $.ternary_expression),
+      alias($._arithmetic_binary_expression, $.binary_expression),
+      alias($._arithmetic_postfix_expression, $.postfix_expression),
+      alias($._arithmetic_parenthesized_expression, $.parenthesized_expression),
+    ),
+
+    _arithmetic_literal: $ => prec(1, choice(
+      $.number,
+      $.subscript,
+      $.simple_expansion,
+      $.expansion,
+      $._simple_variable_name,
+    )),
+
+    _arithmetic_binary_expression: $ => prec.left(2, choice(
+      seq(
+        field('left', $._arithmetic_expression),
+        field('operator', choice(
+          '=', '==', '=~', '!=',
+          '+', '-', '+=', '-=',
+          '*', '/', '*=', '/=',
+          '%', '%=', '**',
+          '<', '>', '<=', '>=',
+          '||', '&&',
+          '<<', '>>', '<<=', '>>=',
+          '&', '|', '^',
+          '&=', '|=', '^=',
+          $.test_operator,
+        )),
+        field('right', $._arithmetic_expression),
+      ),
+    )),
+
+    _arithmetic_ternary_expression: $ => prec.left(
+      seq(
+        field('condition', $._arithmetic_expression),
+        '?',
+        field('consequence', $._arithmetic_expression),
+        ':',
+        field('alternative', $._arithmetic_expression),
+      ),
+    ),
+
+    _arithmetic_unary_expression: $ => choice(
+      prec(1, seq(
+        token(prec(1, choice('-', '+', '~', '++', '--'))),
+        $._arithmetic_expression,
+      )),
+      prec.right(1, seq(
+        choice('!', $.test_operator),
+        $._arithmetic_expression,
+      )),
+    ),
+
+    _arithmetic_postfix_expression: $ => seq(
+      $._arithmetic_expression,
+      choice('++', '--'),
+    ),
+
+    _arithmetic_parenthesized_expression: $ => seq(
+      '(',
+      $._arithmetic_expression,
+      ')',
+    ),
+
 
     concatenation: $ => prec(-1, seq(
       choice(
@@ -591,7 +661,11 @@ module.exports = grammar({
 
     ansi_c_string: _ => /\$'([^']|\\')*'/,
 
-    number: _ => /(0x)?[0-9]+(#[0-9A-Za-z@_]+)?/,
+    number: $ => choice(
+      /-?(0x)?[0-9]+(#[0-9A-Za-z@_]+)?/,
+      // the base can be an expansion
+      seq(/-?(0x)?[0-9]+#/, $.expansion),
+    ),
 
     simple_expansion: $ => seq(
       '$',
@@ -626,7 +700,13 @@ module.exports = grammar({
           $.command_substitution,
         ),
         optional(seq(
-          token(prec(1, '/')),
+          choice(
+            alias(token(prec(1, '/')), '/'),
+            alias(token(prec(1, ',')), ','),
+            alias(token(prec(1, ',,')), ',,'),
+            alias(token(prec(1, '^')), '^'),
+            alias(token(prec(1, '^^')), '^^'),
+          ),
           optional($.regex),
         )),
         repeat(prec.right(choice(
@@ -684,6 +764,7 @@ module.exports = grammar({
 
     test_operator: _ => token(prec(1, seq('-', /[a-zA-Z]+/))),
 
+    _c_terminator: _ => choice(';', '\n', '&'),
     _terminator: _ => choice(';', ';;', '\n', '&'),
   },
 });

script/known-failures.txt

@@ -1,4 +1,3 @@
-examples/bash/tests/arith-for.tests
 examples/bash/tests/arith.tests
 examples/bash/tests/array.tests
 examples/bash/tests/assoc.tests