dynsequence

DynSequence<dyn Trait> is like Vec<Box<dyn Trait>>, but with an optimization that avoids allocations. This works by using multiple larger blocks of memory and storing their pointers in a Vec. This means, the items are randomly accessible, but may not lay in continues memory.

Example

This example stores multiple values the DynSequence and accesses them. (push(...) requires the "unstable" feature (nightly only))

# #[cfg(feature="unstable")] {
use dynsequence::DynSequence;
use std::any::Any;
let mut seq: DynSequence<dyn Any> = DynSequence::new();
seq.push("foo"); 
seq.push(1234);
assert_eq!(Some(&1234), seq.get(1).and_then(|a| a.downcast_ref()));
assert_eq!(Some(&"foo"), seq.get(0).and_then(|a| a.downcast_ref()));
assert!(seq.get(2).is_none());
assert_eq!(None, seq.get(0).and_then(|a| a.downcast_ref::<bool>()));
# }

The following example shows the usage of a macro-hac that also works on stable

use dynsequence::{DynSequence,dyn_sequence};
use std::any::Any;
// construct with macro hack
let mut seq: DynSequence<dyn Any> = dyn_sequence![dyn Any => "foo", 1234];
assert_eq!(Some(&1234), seq.get(1).and_then(|a| a.downcast_ref()));
assert_eq!(Some(&"foo"), seq.get(0).and_then(|a| a.downcast_ref()));
assert!(seq.get(2).is_none());

// push with macro hack
dyn_sequence![dyn Any | &mut seq => {
  push (true);
} ];
assert_eq!(Some(&true), seq.get(2).and_then(|a| a.downcast_ref()));

no_std

This crate should also work without std (with alloc). No additional configuration required.

License

This project is licensed under either of

• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)
• Apache License, Version 2.0, (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)

at your option.

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.