Unicode chars allowed in numbers?

Hi Andrei, et al., I was just looking at README.UNICODE, regarding interpretation of numbers: "we restrict numbers to consist only of ASCII digits," and "Numeric strings are supposed to adhere to the same rules." Is it correct to take that to mean only UChar's with values from '0'-'9'/0x30-0x39 (and 'a'-'z' equivalents for bases > 10)? I ask because in zend_u_strtol(), HANDLE_U_NUMERIC() for array keys, etc., the u_digit() function is used, which also allows non-ASCII, higher-value digit characters, doesn't it? But then in is_numeric_unicode(), when checking for hex numbers, the ASCII values '0' and 'x' are used, which is what I'd expect after reading README.UNICODE. Thanks for any clarification, Matt