modalkit 0.0.25

A library for building applications that use modal editing
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
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165

use crate::editing::cursor::{Cursor, CursorState};
use crate::prelude::{CursorEnd, TargetShape};

/// Result type for functions that provide the option of leaving the cursor in different places.
#[derive(Clone, Debug, Default, Eq, PartialEq)]
pub enum CursorChoice {
    /// One choice of cursor placement.
    Single(Cursor),

    /// The start and end positions of an affected range, and a default choice that may or may not
    /// be inside the range.
    Range(Cursor, Cursor, Cursor),

    /// No choices for cursor placement.
    #[default]
    Empty,
}

impl CursorChoice {
    /// Get a reference to the cursor that would be used in the [CursorState] returned by
    /// [CursorChoice::resolve].
    pub fn get(&self, placement: CursorEnd) -> Option<&Cursor> {
        match (self, placement) {
            (CursorChoice::Empty, _) => None,
            (CursorChoice::Single(_), CursorEnd::Keep) => None,
            (CursorChoice::Single(c), CursorEnd::Start) => Some(c),
            (CursorChoice::Single(c), CursorEnd::End) => Some(c),
            (CursorChoice::Single(c), CursorEnd::Selection) => Some(c),
            (CursorChoice::Single(c), CursorEnd::Auto) => Some(c),
            (CursorChoice::Range(_, _, _), CursorEnd::Keep) => None,
            (CursorChoice::Range(s, _, _), CursorEnd::Start) => Some(s),
            (CursorChoice::Range(_, e, _), CursorEnd::End) => Some(e),
            (CursorChoice::Range(_, e, _), CursorEnd::Selection) => Some(e),
            (CursorChoice::Range(_, _, d), CursorEnd::Auto) => Some(d),
        }
    }

    /// Choose the cursor placement as indicated.
    pub fn resolve(self, placement: CursorEnd) -> Option<CursorState> {
        match (self, placement) {
            (CursorChoice::Empty, _) => None,
            (CursorChoice::Single(_), CursorEnd::Keep) => None,
            (CursorChoice::Single(c), CursorEnd::Start) => Some(c.into()),
            (CursorChoice::Single(c), CursorEnd::End) => Some(c.into()),
            (CursorChoice::Single(c), CursorEnd::Selection) => {
                Some(CursorState::Selection(c.clone(), c, TargetShape::CharWise))
            },
            (CursorChoice::Single(c), CursorEnd::Auto) => Some(c.into()),
            (CursorChoice::Range(_, _, _), CursorEnd::Keep) => None,
            (CursorChoice::Range(s, _, _), CursorEnd::Start) => Some(s.into()),
            (CursorChoice::Range(_, e, _), CursorEnd::End) => Some(e.into()),
            (CursorChoice::Range(s, e, _), CursorEnd::Selection) => {
                Some(CursorState::Selection(e, s, TargetShape::CharWise))
            },
            (CursorChoice::Range(_, _, d), CursorEnd::Auto) => Some(d.into()),
        }
    }
}

impl From<Cursor> for CursorChoice {
    fn from(cursor: Cursor) -> Self {
        CursorChoice::Single(cursor)
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_choice_get() {
        let c2 = Cursor::new(2, 5);
        let c4 = Cursor::new(4, 3);
        let c5 = Cursor::new(5, 0);

        let choice = CursorChoice::Single(c5.clone());
        assert_eq!(choice.get(CursorEnd::Keep), None);
        assert_eq!(choice.get(CursorEnd::Start), Some(&c5));
        assert_eq!(choice.get(CursorEnd::End), Some(&c5));
        assert_eq!(choice.get(CursorEnd::Selection), Some(&c5));
        assert_eq!(choice.get(CursorEnd::Auto), Some(&c5));

        let choice = CursorChoice::Range(c2.clone(), c4.clone(), c5.clone());
        assert_eq!(choice.get(CursorEnd::Keep), None);
        assert_eq!(choice.get(CursorEnd::Start), Some(&c2));
        assert_eq!(choice.get(CursorEnd::End), Some(&c4));
        assert_eq!(choice.get(CursorEnd::Selection), Some(&c4));
        assert_eq!(choice.get(CursorEnd::Auto), Some(&c5));
    }

    #[test]
    fn test_choice_keep() {
        // CursorEnd::Keep always resolves to none.
        let c0 = Cursor::new(0, 0);

        let choice = CursorChoice::Empty;
        assert_eq!(choice.resolve(CursorEnd::Keep), None);

        let choice = CursorChoice::Single(c0.clone());
        assert_eq!(choice.resolve(CursorEnd::Keep), None);

        let choice = CursorChoice::Range(c0.clone(), c0.clone(), c0);
        assert_eq!(choice.resolve(CursorEnd::Keep), None);
    }

    #[test]
    fn test_choice_empty() {
        let ends = vec![
            CursorEnd::Start,
            CursorEnd::End,
            CursorEnd::Selection,
            CursorEnd::Auto,
        ];

        for end in ends.into_iter() {
            // CursorChoice::Empty always resolves to None.
            assert_eq!(CursorChoice::Empty.clone().resolve(end), None);
        }
    }

    #[test]
    fn test_choice_single() {
        let c0 = Cursor::new(0, 1);
        let c3 = Cursor::new(3, 5);
        let cw = TargetShape::CharWise;

        for end in [CursorEnd::Start, CursorEnd::End, CursorEnd::Auto] {
            let choice = CursorChoice::Single(c0.clone());
            assert_eq!(choice.resolve(end).unwrap(), CursorState::Location(Cursor::new(0, 1)));

            let choice = CursorChoice::Single(c3.clone());
            assert_eq!(choice.resolve(end).unwrap(), CursorState::Location(Cursor::new(3, 5)));
        }

        let choice = CursorChoice::Single(c0.clone());
        let state = CursorState::Selection(c0.clone(), c0.clone(), cw);
        assert_eq!(choice.resolve(CursorEnd::Selection).unwrap(), state);

        let choice = CursorChoice::Single(c3.clone());
        let state = CursorState::Selection(c3.clone(), c3.clone(), cw);
        assert_eq!(choice.resolve(CursorEnd::Selection).unwrap(), state);
    }

    #[test]
    fn test_choice_range() {
        let c2 = Cursor::new(2, 5);
        let c4 = Cursor::new(4, 3);
        let c5 = Cursor::new(5, 0);
        let cw = TargetShape::CharWise;

        let choice = CursorChoice::Range(c2.clone(), c4.clone(), c5.clone());

        let state = Some(CursorState::Location(c5.clone()));
        assert_eq!(choice.clone().resolve(CursorEnd::Auto), state);

        let state = Some(CursorState::Location(c2.clone()));
        assert_eq!(choice.clone().resolve(CursorEnd::Start), state);

        let state = Some(CursorState::Location(c4.clone()));
        assert_eq!(choice.clone().resolve(CursorEnd::End), state);

        let state = Some(CursorState::Selection(c4, c2, cw));
        assert_eq!(choice.clone().resolve(CursorEnd::Selection), state);
    }
}