isNamePart function
Implementation
bool isNamePart(int x) =>
char.$a <= x && x <= char.$z ||
char.$A <= x && x <= char.$Z ||
char.$0 <= x && x <= char.$9 ||
x == char.DOLLAR ||
x == char.UNDERSCORE ||
x > 127 &&
(isFancyLetter(x) || unicode.isDecimalNumber(x) || isFancyNamePart(x));