rust-generic-decode.rs

fn decode<'a, T: Decodable<MyDecoder<BufReader<'a>>, IoError>> (&self, key: u64) -> Result<Option<T>, ~str> {
	match self.get(key) {
		Ok(Some(data)) => {
			let reader = BufReader::new(data);
			                         // ^~~~ error: `data` does not live long enough
			                         // because 'a is bound to the function context because of the returned T
			                         // but 'a actually only needs to be temporary (the reader var in this context)
			let mut decoder = MyDecoder::new(reader);
			match Decodable::decode(&mut decoder) {
				Ok(value) => Ok(Some(value)),
				Err(err) => Err(format!("deserialize: {}", err)),
			}
		},
		Ok(None) => Ok(None),
		Err(err) => Err(err),
	}
}