public Grammar loadGrammar(String fileName) {
		GrammarRootAST grammarRootAST = parseGrammar(fileName);
		final Grammar g = createGrammar(grammarRootAST);
		g.fileName = fileName;
		process(g, false);
		return g;
	}
Convenience method to load and process an ANTLR grammar. Useful
 when creating interpreters.  If you need to access to the lexer
 grammar created while processing a combined grammar, use
 getImplicitLexer() on returned grammar.
tool/src/org/antlr/v4/Tool.java