% Output from functions and methods
[FIXME] Add discussion of overly-specific return types, e.g. returning a compound iterator type rather than hiding it behind a use of newtype.
Many functions that answer a question also compute interesting related data. If this data is potentially of interest to the client, consider exposing it in the API.
Prefer
struct SearchResult {
found: bool, // item in container?
expected_index: usize // what would the item's index be?
}
fn binary_search(&self, k: Key) -> SearchResult
or
fn binary_search(&self, k: Key) -> (bool, usize)
over
fn binary_search(&self, k: Key) -> bool
Prefer
fn from_utf8_owned(vv: Vec<u8>) -> Result<String, Vec<u8>>
over
fn from_utf8_owned(vv: Vec<u8>) -> Option<String>
The from_utf8_owned
function gains ownership of a vector. In the successful
case, the function consumes its input, returning an owned string without
allocating or copying. In the unsuccessful case, however, the function returns
back ownership of the original slice.