Antlr4.Automata.LexerATNFactory.CheckRange C# (CSharp) Метод

        protected virtual bool CheckRange(GrammarAST leftNode, GrammarAST rightNode, int leftValue, int rightValue)
        {
            bool result = true;
            if (leftValue == -1)
            {
                result = false;
                g.tool.errMgr.GrammarError(ErrorType.INVALID_LITERAL_IN_LEXER_SET,
                        g.fileName, leftNode.Token, leftNode.Text);
            }
            if (rightValue == -1)
            {
                result = false;
                g.tool.errMgr.GrammarError(ErrorType.INVALID_LITERAL_IN_LEXER_SET,
                        g.fileName, rightNode.Token, rightNode.Text);
            }
            if (!result)
                return result;

            if (rightValue < leftValue)
            {
                g.tool.errMgr.GrammarError(ErrorType.EMPTY_STRINGS_AND_SETS_NOT_ALLOWED,
                        g.fileName, ((GrammarAST)leftNode.Parent).Token, leftNode.Text + ".." + rightNode.Text);
            }
            return result;
        }