Trait std::default::Default
[−]
[src]
pub trait Default { fn default() -> Self; }
A trait for giving a type a useful default value.
A struct can derive default implementations of Default
for basic types using
#[derive(Default)]
.
Examples
#[derive(Default)] struct SomeOptions { foo: i32, bar: f32, }
Required Methods
fn default() -> Self
Returns the "default value" for a type.
Default values are often some kind of initial value, identity value, or anything else that may make sense as a default.
Examples
Using built-in default values:
let i: i8 = Default::default(); let (x, y): (Option<String>, f64) = Default::default(); let (a, b, (c, d)): (i32, u32, (bool, bool)) = Default::default();
Making your own:
enum Kind { A, B, C, } impl Default for Kind { fn default() -> Kind { Kind::A } }
Implementors
impl<T> Default for Wrapping<T> where T: Default
impl<T> Default for PhantomData<T> where T: ?Sized
impl Default for ()
impl Default for bool
impl Default for char
impl Default for usize
impl Default for u8
impl Default for u16
impl Default for u32
impl Default for u64
impl Default for isize
impl Default for i8
impl Default for i16
impl Default for i32
impl Default for i64
impl Default for f32
impl Default for f64
impl<T> Default for [T; 32] where T: Default
impl<T> Default for [T; 31] where T: Default
impl<T> Default for [T; 30] where T: Default
impl<T> Default for [T; 29] where T: Default
impl<T> Default for [T; 28] where T: Default
impl<T> Default for [T; 27] where T: Default
impl<T> Default for [T; 26] where T: Default
impl<T> Default for [T; 25] where T: Default
impl<T> Default for [T; 24] where T: Default
impl<T> Default for [T; 23] where T: Default
impl<T> Default for [T; 22] where T: Default
impl<T> Default for [T; 21] where T: Default
impl<T> Default for [T; 20] where T: Default
impl<T> Default for [T; 19] where T: Default
impl<T> Default for [T; 18] where T: Default
impl<T> Default for [T; 17] where T: Default
impl<T> Default for [T; 16] where T: Default
impl<T> Default for [T; 15] where T: Default
impl<T> Default for [T; 14] where T: Default
impl<T> Default for [T; 13] where T: Default
impl<T> Default for [T; 12] where T: Default
impl<T> Default for [T; 11] where T: Default
impl<T> Default for [T; 10] where T: Default
impl<T> Default for [T; 9] where T: Default
impl<T> Default for [T; 8] where T: Default
impl<T> Default for [T; 7] where T: Default
impl<T> Default for [T; 6] where T: Default
impl<T> Default for [T; 5] where T: Default
impl<T> Default for [T; 4] where T: Default
impl<T> Default for [T; 3] where T: Default
impl<T> Default for [T; 2] where T: Default
impl<T> Default for [T; 1] where T: Default
impl<T> Default for [T; 0]
impl Default for AtomicBool
impl Default for AtomicIsize
impl Default for AtomicUsize
impl<T> Default for AtomicPtr<T>
impl<T> Default for Cell<T> where T: Copy + Default
impl<T> Default for RefCell<T> where T: Default
impl<T> Default for Empty<T>
impl<T> Default for Option<T>
impl<'a, T> Default for &'a [T]
impl<'a, T> Default for &'a mut [T]
impl<'a> Default for &'a str
impl Default for SipHasher
impl<H> Default for BuildHasherDefault<H>
impl<A> Default for (A,) where A: Default
impl<A, B> Default for (A, B) where B: Default, A: Default
impl<A, B, C> Default for (A, B, C) where A: Default, B: Default, C: Default
impl<A, B, C, D> Default for (A, B, C, D) where B: Default, A: Default, C: Default, D: Default
impl<A, B, C, D, E> Default for (A, B, C, D, E) where A: Default, C: Default, D: Default, E: Default, B: Default
impl<A, B, C, D, E, F> Default for (A, B, C, D, E, F) where C: Default, E: Default, A: Default, B: Default, D: Default, F: Default
impl<A, B, C, D, E, F, G> Default for (A, B, C, D, E, F, G) where A: Default, B: Default, E: Default, G: Default, C: Default, F: Default, D: Default
impl<A, B, C, D, E, F, G, H> Default for (A, B, C, D, E, F, G, H) where E: Default, H: Default, C: Default, G: Default, F: Default, A: Default, B: Default, D: Default
impl<A, B, C, D, E, F, G, H, I> Default for (A, B, C, D, E, F, G, H, I) where D: Default, G: Default, E: Default, H: Default, B: Default, C: Default, A: Default, I: Default, F: Default
impl<A, B, C, D, E, F, G, H, I, J> Default for (A, B, C, D, E, F, G, H, I, J) where E: Default, C: Default, F: Default, H: Default, B: Default, J: Default, D: Default, A: Default, G: Default, I: Default
impl<A, B, C, D, E, F, G, H, I, J, K> Default for (A, B, C, D, E, F, G, H, I, J, K) where H: Default, I: Default, D: Default, C: Default, J: Default, E: Default, G: Default, F: Default, B: Default, K: Default, A: Default
impl<A, B, C, D, E, F, G, H, I, J, K, L> Default for (A, B, C, D, E, F, G, H, I, J, K, L) where G: Default, B: Default, K: Default, I: Default, F: Default, C: Default, E: Default, L: Default, D: Default, J: Default, A: Default, H: Default
impl<T> Default for Box<T> where T: Default
impl<T> Default for Box<[T]>
impl<T> Default for Arc<T> where T: Default
impl<T> Default for Rc<T> where T: Default
impl<T> Default for BinaryHeap<T> where T: Ord
impl<K, V> Default for BTreeMap<K, V> where K: Ord
impl<T> Default for BTreeSet<T> where T: Ord
impl<T> Default for LinkedList<T>
impl Default for String
impl<T> Default for Vec<T>
impl<T> Default for VecDeque<T>
impl Default for ReseedWithDefault
impl<K, V, S> Default for HashMap<K, V, S> where K: Eq + Hash, S: HashState + Default
impl Default for RandomState
impl<T, S> Default for HashSet<T, S> where T: Eq + Hash, S: HashState + Default
impl<H> Default for DefaultState<H>
impl Default for Packet