cargo_rdme/
utils.rs

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
166
167
168
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 */

use itertools::Itertools;
use std::ops::Range;

#[derive(Eq, PartialEq, Debug, Clone, Ord, PartialOrd)]
pub struct Span {
    pub start: usize,
    pub end: usize,
}

impl From<Range<usize>> for Span {
    fn from(range: Range<usize>) -> Self {
        Span { start: range.start, end: range.end }
    }
}

#[derive(PartialEq, Eq, Debug)]
pub enum ItemOrOther<'a, T> {
    Item(T),
    Other(&'a str),
}

pub struct MarkdownItemIterator<'a, T> {
    source: &'a str,
    iter: Box<dyn Iterator<Item = (Span, T)> + 'a>,
}

impl<'a, T> MarkdownItemIterator<'a, T> {
    pub fn new(
        source: &'a str,
        iter: impl Iterator<Item = (Span, T)> + 'a,
    ) -> MarkdownItemIterator<'a, T> {
        MarkdownItemIterator { source, iter: Box::new(iter) }
    }

    #[allow(dead_code)]
    pub fn items(self) -> impl Iterator<Item = T> + 'a
    where
        T: 'a,
    {
        self.iter.map(|(_, item)| item)
    }

    #[allow(dead_code)]
    pub fn items_with_spans(self) -> impl Iterator<Item = (Span, T)> + 'a
    where
        T: 'a,
    {
        self.iter
    }

    pub fn complete(self) -> impl Iterator<Item = ItemOrOther<'a, T>>
    where
        T: Clone,
    {
        use std::iter::once;

        once(None)
            .chain(self.iter.map(Some))
            .chain(once(None))
            .tuple_windows()
            .flat_map(|(l, r)| match (l, r) {
                (None, Some((span, _))) => {
                    [ItemOrOther::Other(&self.source[0..span.start]), ItemOrOther::Other("")]
                }
                (Some((span_1, v_1)), Some((span_2, _))) => [
                    ItemOrOther::Item(v_1),
                    ItemOrOther::Other(&self.source[span_1.end..span_2.start]),
                ],
                (Some((span, v)), None) => {
                    [ItemOrOther::Item(v), ItemOrOther::Other(&self.source[span.end..])]
                }
                (None, None) => [ItemOrOther::Other(self.source), ItemOrOther::Other("")],
            })
            .filter(|e| !matches!(e, ItemOrOther::Other("")))
    }
}

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

    #[test]
    fn test_markdown_item_iterator_complete_no_item() {
        let str = "hello world";

        let mut iter = MarkdownItemIterator::<()>::new(str, std::iter::empty()).complete();

        assert_eq!(iter.next(), Some(ItemOrOther::Other("hello world")));
        assert_eq!(iter.next(), None);
    }

    #[test]
    fn test_markdown_item_iterator_complete_item_start() {
        let str = "_hello world";

        let items = [(Span::from(0..1), "x")];

        let mut iter = MarkdownItemIterator::new(str, items.into_iter()).complete();

        assert_eq!(iter.next(), Some(ItemOrOther::Item("x")));
        assert_eq!(iter.next(), Some(ItemOrOther::Other("hello world")));
        assert_eq!(iter.next(), None);
    }

    #[test]
    fn test_markdown_item_iterator_complete_item_end() {
        let str = "hello world_";

        let items = [(Span::from(11..12), "x")];

        let mut iter = MarkdownItemIterator::new(str, items.into_iter()).complete();

        assert_eq!(iter.next(), Some(ItemOrOther::Other("hello world")));
        assert_eq!(iter.next(), Some(ItemOrOther::Item("x")));
        assert_eq!(iter.next(), None);
    }

    #[test]
    fn test_markdown_item_iterator_complete_item_middle() {
        let str = "hello _ world";

        let items = [(Span::from(6..7), "x")];

        let mut iter = MarkdownItemIterator::new(str, items.into_iter()).complete();

        assert_eq!(iter.next(), Some(ItemOrOther::Other("hello ")));
        assert_eq!(iter.next(), Some(ItemOrOther::Item("x")));
        assert_eq!(iter.next(), Some(ItemOrOther::Other(" world")));
        assert_eq!(iter.next(), None);
    }

    #[test]
    fn test_markdown_item_iterator_complete_item_multiple() {
        let str = "hello _ world _ !";

        let items = [(Span::from(6..7), "x"), (Span::from(14..15), "y")];

        let mut iter = MarkdownItemIterator::new(str, items.into_iter()).complete();

        assert_eq!(iter.next(), Some(ItemOrOther::Other("hello ")));
        assert_eq!(iter.next(), Some(ItemOrOther::Item("x")));
        assert_eq!(iter.next(), Some(ItemOrOther::Other(" world ")));
        assert_eq!(iter.next(), Some(ItemOrOther::Item("y")));
        assert_eq!(iter.next(), Some(ItemOrOther::Other(" !")));
        assert_eq!(iter.next(), None);
    }

    #[test]
    fn test_markdown_item_iterator_complete_consecutive() {
        let str = "hello __ world!";

        let items = [(Span::from(6..7), "x"), (Span::from(7..8), "y")];

        let mut iter = MarkdownItemIterator::new(str, items.into_iter()).complete();

        assert_eq!(iter.next(), Some(ItemOrOther::Other("hello ")));
        assert_eq!(iter.next(), Some(ItemOrOther::Item("x")));
        assert_eq!(iter.next(), Some(ItemOrOther::Item("y")));
        assert_eq!(iter.next(), Some(ItemOrOther::Other(" world!")));
        assert_eq!(iter.next(), None);
    }
}