optempty/is_empty/
mod.rs

1mod no_std;
2#[cfg(all(feature = "querymap", feature = "std"))]
3mod query_map;
4#[cfg(feature = "serdejson")]
5mod serde_json;
6#[cfg(feature = "std")]
7mod std;
8
9pub use self::no_std::*;
10#[cfg(all(feature = "querymap", feature = "std"))]
11pub use self::query_map::*;
12#[cfg(feature = "serdejson")]
13pub use self::serde_json::*;
14#[cfg(feature = "std")]
15pub use self::std::*;
16
17/// Used to determine if a collection, or `Option<T>` or `Result<T, E>` (where
18/// `T` implements `IsEmpty`) is empty.
19///
20/// `IsEmpty` is implemented for the standard collections, and more.
21pub trait IsEmpty {
22    /// Returns `true` if it is empty.
23    fn is_empty(&self) -> bool;
24}