gistfile1.txt

enum ShadowSpecifiedValue {
  None,
  struct Shadow shdw
}

struct Shadow {
  ...
}

pub fn parse(context: &ParserContext, input: &mut Parser) -> Result<Shadow, ()> {

  if input.try(|input| input.expect_ident_matching("none")).is_ok() {
    ok(ShadowSpecifiedValue::None)
  } else {
        try!(Length::parse(input).map(ShadowSpecifiedValue::shdw::offset_x);
        try!(Length::parse(input).map(ShadowSpecifiedValue::shdw::offset_y);
        try!(Length::parse_nonnegative(input).map(ShadowSpecifiedValue::shdw::blur_radius);
        try!(Length::parse(input).map(ShadowSpecifiedValue::shdw::spread_radius);
        try!(CSSColor::parse(input).map(ShadowSpecifiedValue::shdw::color);
        if input.try(|input| input.expect_ident_matching("inset")).is_ok() {
            ShadowSpecifiedValue::shdw::inset = true;
        } else{
            ShadowSpecifiedValue::shdw::inset = false;
        }

  }
}