Stub in an until statement.

grammar.js

@@ -19,6 +19,7 @@ module.exports = grammar({
       seq($._statement, "if", $._expression),
       seq($._statement, "while", $._expression),
       seq($._statement, "unless", $._expression),
+      seq($._statement, "until", $._expression),
       $._expression
     ),
 

grammar_test/statements.txt

@@ -27,3 +27,13 @@ foo unless bar
 ---
 
 (program (identifier) (identifier))
+
+================
+until statement
+================
+
+foo until bar
+
+---
+
+(program (identifier) (identifier))

src/grammar.json

@@ -146,6 +146,23 @@
             }
           ]
         },
+        {
+          "type": "SEQ",
+          "members": [
+            {
+              "type": "SYMBOL",
+              "name": "_statement"
+            },
+            {
+              "type": "STRING",
+              "value": "until"
+            },
+            {
+              "type": "SYMBOL",
+              "name": "_expression"
+            }
+          ]
+        },
         {
           "type": "SYMBOL",
           "name": "_expression"