+static bool is_universal_char_valid(utf32 const v)
+{
+ /* C11 ยง6.4.3:2 */
+ if (v < 0xA0U && v != 0x24 && v != 0x40 && v != 0x60)
+ return false;
+ if (0xD800 <= v && v <= 0xDFFF)
+ return false;
+ return true;
+}
+
+static int digit_value(utf32 digit);
+
+static utf32 parse_universal_char(unsigned const n_digits)
+{
+ utf32 v = 0;
+ for (unsigned k = n_digits; k != 0; --k) {
+ if (isxdigit(c)) {
+ v = 16 * v + digit_value(c);
+ next_char();
+ } else {
+ errorf(&lexer_pos, "short universal character name, expected %u more digits", k);
+ break;
+ }
+ }
+ if (!is_universal_char_valid(v)) {
+ errorf(&lexer_pos, "\\%c%0*X is not a valid universal character name", n_digits == 4 ? 'u' : 'U', (int)n_digits, v);
+ }
+ return v;
+}
+
+static bool is_universal_char_valid_identifier(utf32 const v)
+{
+ /* C11 Annex D.1 */
+ if ( v == 0x000A8) return true;
+ if ( v == 0x000AA) return true;
+ if ( v == 0x000AD) return true;
+ if ( v == 0x000AF) return true;
+ if (0x000B2 <= v && v <= 0x000B5) return true;
+ if (0x000B7 <= v && v <= 0x000BA) return true;
+ if (0x000BC <= v && v <= 0x000BE) return true;
+ if (0x000C0 <= v && v <= 0x000D6) return true;
+ if (0x000D8 <= v && v <= 0x000F6) return true;
+ if (0x000F8 <= v && v <= 0x000FF) return true;
+ if (0x00100 <= v && v <= 0x0167F) return true;
+ if (0x01681 <= v && v <= 0x0180D) return true;
+ if (0x0180F <= v && v <= 0x01FFF) return true;
+ if (0x0200B <= v && v <= 0x0200D) return true;
+ if (0x0202A <= v && v <= 0x0202E) return true;
+ if (0x0203F <= v && v <= 0x02040) return true;
+ if ( v == 0x02054) return true;
+ if (0x02060 <= v && v <= 0x0206F) return true;
+ if (0x02070 <= v && v <= 0x0218F) return true;
+ if (0x02460 <= v && v <= 0x024FF) return true;
+ if (0x02776 <= v && v <= 0x02793) return true;
+ if (0x02C00 <= v && v <= 0x02DFF) return true;
+ if (0x02E80 <= v && v <= 0x02FFF) return true;
+ if (0x03004 <= v && v <= 0x03007) return true;
+ if (0x03021 <= v && v <= 0x0302F) return true;
+ if (0x03031 <= v && v <= 0x0303F) return true;
+ if (0x03040 <= v && v <= 0x0D7FF) return true;
+ if (0x0F900 <= v && v <= 0x0FD3D) return true;
+ if (0x0FD40 <= v && v <= 0x0FDCF) return true;
+ if (0x0FDF0 <= v && v <= 0x0FE44) return true;
+ if (0x0FE47 <= v && v <= 0x0FFFD) return true;
+ if (0x10000 <= v && v <= 0x1FFFD) return true;
+ if (0x20000 <= v && v <= 0x2FFFD) return true;
+ if (0x30000 <= v && v <= 0x3FFFD) return true;
+ if (0x40000 <= v && v <= 0x4FFFD) return true;
+ if (0x50000 <= v && v <= 0x5FFFD) return true;
+ if (0x60000 <= v && v <= 0x6FFFD) return true;
+ if (0x70000 <= v && v <= 0x7FFFD) return true;
+ if (0x80000 <= v && v <= 0x8FFFD) return true;
+ if (0x90000 <= v && v <= 0x9FFFD) return true;
+ if (0xA0000 <= v && v <= 0xAFFFD) return true;
+ if (0xB0000 <= v && v <= 0xBFFFD) return true;
+ if (0xC0000 <= v && v <= 0xCFFFD) return true;
+ if (0xD0000 <= v && v <= 0xDFFFD) return true;
+ if (0xE0000 <= v && v <= 0xEFFFD) return true;
+ return false;
+}
+
+static bool is_universal_char_valid_identifier_start(utf32 const v)
+{
+ /* C11 Annex D.2 */
+ if (0x0300 <= v && v <= 0x036F) return false;
+ if (0x1DC0 <= v && v <= 0x1DFF) return false;
+ if (0x20D0 <= v && v <= 0x20FF) return false;
+ if (0xFE20 <= v && v <= 0xFE2F) return false;
+ return true;
+}
+