private boolean EXPONENT_VALUE_sempred(RuleContext _localctx, int predIndex) {
		switch (predIndex) {
		case 0:
			return isValidDecimal();
		}
		return true;
	}
This method will be called when the character stream ends and try to find out the
unclosed bracketed comment.
If the method be called, it means the end of the entire character stream match,
and we set the flag and fail later.
amoro-format-mixed/amoro-mixed-spark/v3.3/amoro-mixed-spark-3.3/src/main/gen-antlr/org/apache/amoro/spark/sql/parser/MixedFormatSqlExtendLexer.java