aboutsummaryrefslogtreecommitdiffstats
path: root/src/util/line_ending.rs
blob: a018fe8b74b6e733a4baaa1f58386a8bc930545a (plain) (blame)
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
extern crate alloc;

use alloc::{str::FromStr, string::String};

/// Type of line endings in markdown.
///
/// Particularly when working with Windows, you might want to use
/// `LineEnding::CarriageReturnLineFeed`.
///
/// ## Examples
///
/// ```
/// use markdown::LineEnding;
/// # fn main() {
///
/// // Use a CR + LF combination:
/// let crlf = LineEnding::CarriageReturnLineFeed;
/// # }
/// ```
#[derive(Clone, Debug, Default, Eq, PartialEq)]
pub enum LineEnding {
    /// Both a carriage return (`\r`) and a line feed (`\n`).
    ///
    /// ## Example
    ///
    /// ```markdown
    /// a␍␊
    /// b
    /// ```
    CarriageReturnLineFeed,
    /// Sole carriage return (`\r`).
    ///
    /// ## Example
    ///
    /// ```markdown
    /// a␍
    /// b
    /// ```
    CarriageReturn,
    /// Sole line feed (`\n`).
    ///
    /// ## Example
    ///
    /// ```markdown
    /// a␊
    /// b
    /// ```
    #[default]
    LineFeed,
}

// xxxxxxxxxxxxxxx
impl LineEnding {
    /// Turn the line ending into a [str].
    #[must_use]
    pub fn as_str(&self) -> &str {
        match self {
            LineEnding::CarriageReturnLineFeed => "\r\n",
            LineEnding::CarriageReturn => "\r",
            LineEnding::LineFeed => "\n",
        }
    }
}

impl FromStr for LineEnding {
    type Err = String;

    /// Turn a string into a line ending.
    ///
    /// ## Panics
    ///
    /// Panics if `code` is not `\r\n`, `\r`, or `\n`.
    fn from_str(s: &str) -> Result<Self, Self::Err> {
        match s {
            "\r\n" => Ok(LineEnding::CarriageReturnLineFeed),
            "\r" => Ok(LineEnding::CarriageReturn),
            "\n" => Ok(LineEnding::LineFeed),
            _ => Err("Expected CR, LF, or CRLF".into()),
        }
    }
}

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

    #[test]
    fn test_line_ending() {
        assert_eq!(
            "\r".parse(),
            Ok(LineEnding::CarriageReturn),
            "should support turning a string into a carriage return"
        );
        assert_eq!(
            LineEnding::CarriageReturn.as_str(),
            "\r",
            "should support turning a carriage return into a string"
        );

        assert_eq!(
            "\n".parse(),
            Ok(LineEnding::LineFeed),
            "should support turning a string into a line feed"
        );
        assert_eq!(
            LineEnding::LineFeed.as_str(),
            "\n",
            "should support turning a line feed into a string"
        );

        assert_eq!(
            "\r\n".parse(),
            Ok(LineEnding::CarriageReturnLineFeed),
            "should support turning a string into a carriage return + line feed"
        );
        assert_eq!(
            LineEnding::CarriageReturnLineFeed.as_str(),
            "\r\n",
            "should support turning a carriage return + line feed into a string"
        );

        assert_eq!(
            "aaa".parse::<LineEnding>(),
            Err("Expected CR, LF, or CRLF".into()),
            "should error when parsing a non-eol"
        );
    }
}