[Syntax] Allow empty arguments

Author: nikitaeverywhere

package.json

@@ -5,7 +5,7 @@
   "printableName": "Cache Web Terminal",
   "description": "Web-based terminal emulator for Caché administering.",
   "author": "ZitRo",
-  "version": "4.7.1",
+  "version": "4.7.2",
   "gaID": "UA-83005064-2",
   "releaseNumber": 26,
   "scripts": {

src/client/js/parser/grammar.js

@@ -833,6 +833,7 @@ rule("argumentList").split(
 
 rule("nonEmptyArgumentList").branch().split(
     char({ value: ".", class: "argument" }).id({ class: "argument" }),
+    char(",").optWhitespace().merge(),
     call("expression")
 ).split(
     char(",").optWhitespace().merge(),