如何有效地使用非默认NLS_NUMERIC_CHARACTERS在Oracle PL/SQL中将文本转换为数字?

I'm trying to find an efficient, generic way to convert from string to a number in PL/SQL, where the local setting for NLS_NUMERIC_CHARACTERS settings is inpredictable -- and preferable I won't touch it. The input format is the programming standard "123.456789", but with an unknown number of digits on each side of the decimal point.I'm trying to find an efficient, generic way to