Macro bump_scope::bump_vec
source · macro_rules! bump_vec { [in $bump:expr] => { ... }; [in $bump:expr; $($values:expr),* $(,)?] => { ... }; [in $bump:expr; $value:expr; $count:expr] => { ... }; [try in $bump:expr] => { ... }; [try in $bump:expr; $($values:expr),* $(,)?] => { ... }; [try in $bump:expr; $value:expr; $count:expr] => { ... }; }
Expand description
This is like vec!
but allocates inside a Bump
or BumpScope
, returning a BumpVec
.
$bump
can be a Bump
or BumpScope
(anything where $bump.as_scope()
returns a &BumpScope
).
§Panics
If used without try
, panics on allocation failure.
§Errors
If used with try
, errors on allocation failure.
§Examples
There are three forms of this macro:
- Create an empty
BumpVec
:
let vec: BumpVec<i32> = bump_vec![in bump];
assert!(vec.is_empty());
- Create a
BumpVec
containing a given list of elements:
let vec = bump_vec![in bump; 1, 2, 3];
assert_eq!(vec[0], 1);
assert_eq!(vec[1], 2);
assert_eq!(vec[2], 3);
- Create a
BumpVec
from a given element and size:
let vec = bump_vec![in bump; 1; 3];
assert_eq!(vec, [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, bump_vec![in bump; 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.
Also, note that bump_vec![in bump; expr; 0]
is allowed, and produces an empty vector.
This will still evaluate expr
, however, and immediately drop the resulting value, so
be mindful of side effects.