String combinedGrammarFileName = null;
String lexerGrammarFileName = null;
String parserGrammarFileName = null;
// load to examine it
Grammar g = antlr.loadGrammar(grammarFileName);
// examine's Grammar AST from v4 itself;
// hence use ANTLRParser.X not ANTLRv4Parser from this plugin
switch (g.getType()) {
case ANTLRParser.PARSER: