macro_rules! smallvec { (@one $x:expr) => { ... }; ($elem:expr; $n:expr) => { ... }; ($($x:expr),*$(,)*) => { ... }; }
Expand description
Creates a SmallVec
containing the arguments.
smallvec!
allows SmallVec
s to be defined with the same syntax as array expressions.
There are two forms of this macro:
- Create a
SmallVec
containing a given list of elements:
let v: SmallVec<[_; 128]> = smallvec![1, 2, 3];
assert_eq!(v[0], 1);
assert_eq!(v[1], 2);
assert_eq!(v[2], 3);
- Create a
SmallVec
from a given element and size:
let v: SmallVec<[_; 0x8000]> = smallvec![1; 3];
assert_eq!(v, SmallVec::from_buf([1, 1, 1]));
Note that unlike array expressions this syntax supports all elements
which implement Clone
and the number of elements doesn’t have to be
a constant.
This will use clone
to duplicate an expression, so one should be careful
using this with types having a nonstandard Clone
implementation. For
example, smallvec![Rc::new(1); 5]
will create a vector of five references
to the same boxed integer value, not five references pointing to independently
boxed integers.