undo

Provides undo-redo functionality with dynamic dispatch and automatic command merging.

• [Record] provides a stack based undo-redo functionality.
• [History] provides a tree based undo-redo functionality that allows you to jump between different branches.
• [Queue] wraps a [Record] or [History] and provides batch queue functionality.
• [Checkpoint] wraps a [Record] or [History] and provides checkpoint functionality.
• Commands can be merged using the [merge!] macro or the [merge] method. When two commands are merged, undoing and redoing them are done in a single step.
• Configurable display formatting is provided when the display feature is enabled.
• Time stamps and time travel is provided when the chrono feature is enabled.

Examples

Add this to Cargo.toml:

toml [dependencies] undo = "0.28"

And this to main.rs:

```rust extern crate undo;

use undo::{Command, Record};

[derive(Debug)]

struct Add(char);

impl Command for Add { fn apply(&mut self, s: &mut String) -> Result<(), Box> { s.push(self.0); Ok(()) }

fn undo(&mut self, s: &mut String) -> Result<(), Box<dyn Error + Send + Sync>> {
    self.0 = s.pop().ok_or("`s` is empty")?;
    Ok(())
}

}

fn main() -> Result<(), Box> { let mut record = Record::default(); record.apply(Add('a'))?; record.apply(Add('b'))?; record.apply(Add('c'))?; asserteq!(record.asreceiver(), "abc");

record.undo().unwrap()?;
record.undo().unwrap()?;
record.undo().unwrap()?;
assert_eq!(record.as_receiver(), "");

record.redo().unwrap()?;
record.redo().unwrap()?;
record.redo().unwrap()?;
assert_eq!(record.as_receiver(), "abc");
Ok(())

} ```

License

Licensed under either of

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

at your option.

Contribution

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.