private char uniEscape() throws java.io.IOException, jasError {
int res = 0;
for (int i = 0; i < 4; i++) {
advance();
if (next_char == -1) return 0;
int tmp = Character.digit((char) next_char, 16);
if (tmp == -1) throw new jasError("Bad '\\u' escape sequence");
res = (res << 4) | tmp;
}
return (char) res;
}
