undo 0.52.0

An undo-redo library.
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75

use undo::{Add, Record};

const A: Add = Add('a');
const B: Add = Add('b');
const C: Add = Add('c');
const D: Add = Add('d');
const E: Add = Add('e');
const F: Add = Add('f');

#[test]
fn go_to() {
    let mut target = String::new();
    let mut record = Record::new();
    record.edit(&mut target, A);
    record.edit(&mut target, B);
    record.edit(&mut target, C);
    record.edit(&mut target, D);
    record.edit(&mut target, E);

    record.go_to(&mut target, 0);
    assert_eq!(record.head(), 0);
    assert_eq!(target, "");
    record.go_to(&mut target, 5);
    assert_eq!(record.head(), 5);
    assert_eq!(target, "abcde");
    record.go_to(&mut target, 1);
    assert_eq!(record.head(), 1);
    assert_eq!(target, "a");
    record.go_to(&mut target, 4);
    assert_eq!(record.head(), 4);
    assert_eq!(target, "abcd");
    record.go_to(&mut target, 2);
    assert_eq!(record.head(), 2);
    assert_eq!(target, "ab");
    record.go_to(&mut target, 3);
    assert_eq!(record.head(), 3);
    assert_eq!(target, "abc");
    assert!(record.go_to(&mut target, 6).is_empty());
    assert_eq!(record.head(), 3);
}

#[test]
fn edits() {
    let mut target = String::new();
    let mut record = Record::new();
    record.edit(&mut target, A);
    record.edit(&mut target, B);
    let collected = record.entries().map(AsRef::as_ref).collect::<Vec<_>>();
    assert_eq!(&collected[..], &[&A, &B][..]);
}

#[test]
fn checkpoint_saved() {
    let mut target = String::new();
    let mut record = Record::new();
    record.edit(&mut target, A);
    record.edit(&mut target, B);
    record.edit(&mut target, C);
    record.set_saved();
    record.undo(&mut target).unwrap();
    record.undo(&mut target).unwrap();
    record.undo(&mut target).unwrap();
    let mut cp = record.checkpoint();
    cp.edit(&mut target, D);
    cp.edit(&mut target, E);
    cp.edit(&mut target, F);
    assert_eq!(target, "def");
    cp.cancel(&mut target);
    assert_eq!(target, "");
    record.redo(&mut target).unwrap();
    record.redo(&mut target).unwrap();
    record.redo(&mut target).unwrap();
    assert!(record.is_saved());
    assert_eq!(target, "abc");
}