Add missing function definition forms

corpus/control_flow.txt

@@ -129,8 +129,20 @@ function do_something_else() {
   echo ok
 }
 
+function do_yet_another_thing {
+  echo ok
+} 2>&1
+
 ---
 
 (program
-  (function_definition (word) (compound_statement (command (command_name (word)) (word))))
-  (function_definition (word) (compound_statement (command (command_name (word)) (word)))))
+  (function_definition
+    (word)
+    (compound_statement (command (command_name (word)) (word))))
+  (function_definition
+    (word)
+    (compound_statement (command (command_name (word)) (word))))
+  (function_definition
+    (word)
+    (compound_statement (command (command_name (word)) (word)))
+    (file_redirect (file_descriptor) (word))))

grammar.js

@@ -124,9 +124,9 @@ module.exports = grammar({
     function_definition: $ => seq(
       optional('function'),
       $.word,
-      '(',
-      ')',
-      $.compound_statement
+      optional(seq('(', ')')),
+      $.compound_statement,
+      optional($.file_redirect)
     ),
 
     compound_statement: $ => seq(

src/grammar.json

@@ -330,16 +330,41 @@
           "name": "word"
         },
         {
-          "type": "STRING",
-          "value": "("
-        },
-        {
-          "type": "STRING",
-          "value": ")"
+          "type": "CHOICE",
+          "members": [
+            {
+              "type": "SEQ",
+              "members": [
+                {
+                  "type": "STRING",
+                  "value": "("
+                },
+                {
+                  "type": "STRING",
+                  "value": ")"
+                }
+              ]
+            },
+            {
+              "type": "BLANK"
+            }
+          ]
         },
         {
           "type": "SYMBOL",
           "name": "compound_statement"
+        },
+        {
+          "type": "CHOICE",
+          "members": [
+            {
+              "type": "SYMBOL",
+              "name": "file_redirect"
+            },
+            {
+              "type": "BLANK"
+            }
+          ]
         }
       ]
     },