On 9/18/19 11:10 AM, Nikita Glukhov wrote: > 4. Even if the Unicode escape sequence '\uXXXX' is used, it cannot produce > special symbols or whitespace, because the identifiers are displayed > ... > I don't know if it is possible to check Unicode properties "ID_Start" and > "ID_Continue" in Postgres, and what ZWNJ/ZWJ is.
ZWNJ and ZWJ are U+200C and U+200D (mentioned in [1]). Also, it's not just that a Unicode escape sequence can't make a special symbol or whitespace; it can't make any character that's not allowed there by the other rules: "A UnicodeEscapeSequence cannot be used to put a code point into an IdentifierName that would otherwise be illegal. In other words, if a \ UnicodeEscapeSequence sequence were replaced by the SourceCharacter it contributes, the result must still be a valid IdentifierName that has the exact same sequence of SourceCharacter elements as the original IdentifierName. All interpretations of IdentifierName within this specification are based upon their actual code points regardless of whether or not an escape sequence was used to contribute any particular code point." A brief glance through src/backend/utils/mb/Unicode shows that the Makefile does download a bunch of stuff, but maybe not the Unicode character data that would allow testing ID_Start and ID_Continue? I'm not sure. Regards, -Chap
