beancount_parser/
date.rs

1use std::{cmp::Ordering, str::FromStr};
2
3use nom::{
4    bytes::complete::take,
5    character::complete::{char, digit1},
6    combinator::{all_consuming, cut, map_res, peek, verify},
7    Finish, Parser,
8};
9
10use super::{IResult, Span};
11
12/// A date
13///
14/// The parser has some sanity checks to make sure the date remotely makes sense
15/// but it doesn't verify if it is an actual real valid date.
16///
17/// If that is important to you, you should use a date-time library to verify the validity.
18///
19/// # Example
20///
21/// ```
22/// # use beancount_parser::BeancountFile;
23/// let input = "2022-05-21 event \"location\" \"Middle earth\"";
24/// let beancount: BeancountFile<f64> = input.parse().unwrap();
25/// let date = beancount.directives[0].date;
26/// assert_eq!(date.year, 2022);
27/// assert_eq!(date.month, 5);
28/// assert_eq!(date.day, 21);
29/// ```
30#[derive(Debug, Copy, Clone, Eq, PartialEq)]
31pub struct Date {
32    /// Year
33    pub year: u16,
34    /// Month (of year)
35    pub month: u8,
36    /// Day (of month)
37    pub day: u8,
38}
39
40impl Date {
41    /// Create a new date from year, month and day
42    #[must_use]
43    pub fn new(year: u16, month: u8, day: u8) -> Self {
44        Self { year, month, day }
45    }
46}
47
48impl PartialOrd for Date {
49    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
50        Some(self.cmp(other))
51    }
52}
53
54impl Ord for Date {
55    fn cmp(&self, other: &Self) -> Ordering {
56        self.year
57            .cmp(&other.year)
58            .then_with(|| self.month.cmp(&other.month))
59            .then_with(|| self.day.cmp(&other.day))
60    }
61}
62
63impl FromStr for Date {
64    type Err = crate::Error;
65
66    fn from_str(s: &str) -> Result<Self, Self::Err> {
67        let span = Span::new(s);
68        match all_consuming(parse).parse(span).finish() {
69            Ok((_, date)) => Ok(date),
70            Err(_) => Err(crate::Error::new(s, span)),
71        }
72    }
73}
74
75pub(super) fn parse(input: Span<'_>) -> IResult<'_, Date> {
76    let (input, _) = peek((digit1, char('-'), digit1, char('-'), digit1)).parse(input)?;
77    cut(do_parse).parse(input)
78}
79
80fn do_parse(input: Span<'_>) -> IResult<'_, Date> {
81    let (input, year) = year(input)?;
82    let (input, _) = char('-')(input)?;
83    let (input, month) = month(input)?;
84    let (input, _) = char('-')(input)?;
85    let (input, day) = day(input)?;
86    Ok((input, Date { year, month, day }))
87}
88
89fn year(input: Span<'_>) -> IResult<'_, u16> {
90    map_res(take(4usize), |s: Span<'_>| s.fragment().parse()).parse(input)
91}
92
93fn month(input: Span<'_>) -> IResult<'_, u8> {
94    verify(
95        map_res(take(2usize), |s: Span<'_>| s.fragment().parse()),
96        |&n| n > 0 && n < 13,
97    )
98    .parse(input)
99}
100
101fn day(input: Span<'_>) -> IResult<'_, u8> {
102    verify(
103        map_res(take(2usize), |s: Span<'_>| s.fragment().parse()),
104        |&n| n > 0 && n < 32,
105    )
106    .parse(input)
107}
108
109#[cfg(test)]
110mod tests {
111    use super::*;
112
113    #[test]
114    fn date_from_str_should_parse_valid_date() {
115        let date: Date = "2023-03-12".parse().unwrap();
116        assert_eq!(date.year, 2023);
117        assert_eq!(date.month, 3);
118        assert_eq!(date.day, 12);
119    }
120
121    #[test]
122    fn date_from_str_should_not_parse_invalid_date() {
123        let result: Result<Date, _> = "2023-03-12oops".parse();
124        assert!(result.is_err(), "{result:?}");
125    }
126}
beancount_parser/date.rs

beancount_parser/
date.rs
