Crate undo [−] [src]
A undo/redo library.
It uses the Command Pattern where the user
implements the UndoCmd
trait for each command and then the commands can be used with the
UndoStack
.
The UndoStack
has two different states, the clean state and the dirty state. The UndoStack
is in a clean state when there are no more commands that can be redone, otherwise it's in a dirty
state.
Example
use std::rc::Rc; use std::cell::RefCell; use undo::{UndoCmd, UndoStack}; /// Pops an element from a vector. #[derive(Clone)] struct PopCmd { vec: Rc<RefCell<Vec<i32>>>, e: Option<i32>, } impl UndoCmd for PopCmd { fn redo(&mut self) { self.e = self.vec.borrow_mut().pop(); } fn undo(&mut self) { self.vec.borrow_mut().push(self.e.unwrap()); self.e = None; } } // We need to use Rc<RefCell> since all commands are going to mutate the vec. let vec = Rc::new(RefCell::new(vec![0, 1, 2, 3, 4, 5, 6, 7, 8, 9])); let mut undo_stack = UndoStack::new() .on_clean(|| println!("This is called when the stack changes from dirty to clean!")) .on_dirty(|| println!("This is called when the stack changes from clean to dirty!")); let cmd = PopCmd { vec: vec.clone(), e: None }; undo_stack.push(cmd.clone()); undo_stack.push(cmd.clone()); undo_stack.push(cmd.clone()); assert_eq!(vec.borrow().len(), 7); undo_stack.undo(); // on_dirty is going to be called here. undo_stack.undo(); undo_stack.undo(); assert_eq!(vec.borrow().len(), 10);
Structs
UndoStack |
|
Traits
UndoCmd |
Every command needs to implement the |