> I'll never understand why the Unicode Consortium chose to exclude emojis from the ID_START and ID_CONTINUE character classes [1] (in terms of which so many pr

> I'll never understand why the Unicode Consortium chose to exclude emojis from the ID_START and ID_CONTINUE character classes [1] (in terms of which so many programming languages define their concept of a valid identifer). Emojis are essentially colored symbols in terms of Unicode general categories and many languages do not accept symbols in an identifier, so it's no surprise that emojis are handled equally. UTR #31 does have a profile for identifiers with emoji (see the section 7.2), but it also demonstrates why it can't be a default: there are cases where `AB` is not valid but `ABC` is valid for some characters A, B and C. So character classes can't fully describe identifiers with emoji after all! (And in fact, many Unicode character classes were defined only for describing standard algorithms.) You need a full emoji regular expression to define such identifiers. > [2] "The formal syntax provided here captures the general intent that an identifier consists of a string of characters beginning with a letter or an ideograph, and followed by any number of letters, ideographs, digits, or underscores" (Emphases original) Unicode has an unfortunate but particular definition of "ideograph", defined in the third sense of [1]. As a rule of thumb you should always mentally replace it with "Han character", which is not an ideogram (like numerals) but a logogram. This misnomer was too old to fix so Unicode decided to go with it. [1] https://unicode.org/glossary/#ideograph https://unicode.org/glossary/#ideograph