isIdentifierStartExpr static method
Pseudo function expressions identifiers can't have a minus sign.
Implementation
static bool isIdentifierStartExpr(int c) =>
(c >= 97 /*a*/ && c <= 122 /*z*/) ||
(c >= 65 /*A*/ && c <= 90 /*Z*/) ||
// Note: Unicode 10646 chars U+00A0 or higher are allowed, see:
// http://www.w3.org/TR/CSS21/syndata.html#value-def-identifier
// http://www.w3.org/TR/CSS21/syndata.html#characters
// Also, escaped character should be allowed.
c == 95 /*_*/ ||
c >= 0xA0 ||
c == 92 /*\*/;