Crate redo

Provides undo-redo functionality with static dispatch and manual command merging.

Contents

• 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 extends them with queue functionality.
• Checkpoint wraps a Record or History and extends them with checkpoint functionality.
• Commands can be merged using the merge method. When two commands are merged, undoing and redoing them are done in a single step.
• Configurable display formatting is provided through the Display structure.
• Time stamps and time travel is provided when the chrono feature is enabled.
• Serialization and deserialization is provided when the serde feature is enabled.

Examples

Add this to Cargo.toml:

[dependencies]
redo = "0.30"

And this to main.rs:

use redo::{Command, Record};

#[derive(Debug)]
struct Add(char);

impl Command<String> for Add {
    type Error = &'static str;

    fn apply(&mut self, s: &mut String) -> Result<(), Self::Error> {
        s.push(self.0);
        Ok(())
    }

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

fn main() -> redo::Result<String, Add> {
    let mut record = Record::default();
    record.apply(Add('a'))?;
    record.apply(Add('b'))?;
    record.apply(Add('c'))?;
    assert_eq!(record.as_receiver(), "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(())
}

Structs

Checkpoint	A checkpoint wrapper.
Display	Configurable display formatting of structures.
Error	An error which holds the command that caused it.
History	A history of commands.
HistoryBuilder	Builder for a History.
Queue	A command queue wrapper.
Record	A record of commands.
RecordBuilder	Builder for a record.

Enums

Merge	The result of merging two commands.
Signal	The signal sent when the record, the history, or the receiver changes.

Traits

Command

Base functionality for all commands.

Type Definitions

Result

A specialized Result type for undo-redo operations.