Add function definitions

corpus/control_flow.txt

@@ -97,3 +97,21 @@ Subshells
 
 (program
   (subshell (command (command_name) (argument))))
+
+===============================
+Function definitions
+===============================
+
+do_something() {
+  echo ok
+}
+
+function do_something_else() {
+  echo ok
+}
+
+---
+
+(program
+  (function_definition (command_name) (compound_command (command (command_name) (argument))))
+  (function_definition (command_name) (compound_command (command (command_name) (argument)))))

grammar.js

@@ -33,7 +33,8 @@ module.exports = grammar({
       $.case_statement,
       $.pipeline,
       $.list,
-      $.subshell
+      $.subshell,
+      $.function_definition
     ),
 
     while_statement: $ => seq(
@@ -87,6 +88,20 @@ module.exports = grammar({
       ';;'
     ),
 
+    function_definition: $ => seq(
+      optional('function'),
+      rename($.leading_word, 'command_name'),
+      '(',
+      ')',
+      $.compound_command
+    ),
+
+    compound_command: $ => seq(
+      '{',
+      repeat($._terminated_statement),
+      '}'
+    ),
+
     bracket_command: $ => choice(
       seq('[', repeat1($.value), ']'),
       seq('[[', repeat1($.value), ']]')

src/grammar.json

@@ -59,6 +59,10 @@
         {
           "type": "SYMBOL",
           "name": "subshell"
+        },
+        {
+          "type": "SYMBOL",
+          "name": "function_definition"
         }
       ]
     },
@@ -254,6 +258,63 @@
         }
       ]
     },
+    "function_definition": {
+      "type": "SEQ",
+      "members": [
+        {
+          "type": "CHOICE",
+          "members": [
+            {
+              "type": "STRING",
+              "value": "function"
+            },
+            {
+              "type": "BLANK"
+            }
+          ]
+        },
+        {
+          "type": "RENAME",
+          "content": {
+            "type": "SYMBOL",
+            "name": "leading_word"
+          },
+          "value": "command_name"
+        },
+        {
+          "type": "STRING",
+          "value": "("
+        },
+        {
+          "type": "STRING",
+          "value": ")"
+        },
+        {
+          "type": "SYMBOL",
+          "name": "compound_command"
+        }
+      ]
+    },
+    "compound_command": {
+      "type": "SEQ",
+      "members": [
+        {
+          "type": "STRING",
+          "value": "{"
+        },
+        {
+          "type": "REPEAT",
+          "content": {
+            "type": "SYMBOL",
+            "name": "_terminated_statement"
+          }
+        },
+        {
+          "type": "STRING",
+          "value": "}"
+        }
+      ]
+    },
     "bracket_command": {
       "type": "CHOICE",
       "members": [