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

//! Defines parser for the Ledger format.

mod character;
mod combinator;
mod directive;
mod expr;
mod metadata;
mod posting;
mod primitive;
mod transaction;

#[cfg(test)]
pub mod testing;

use crate::repl;

use winnow::{
    ascii::line_ending,
    combinator::{alt, cut_err, fail, peek, preceded, repeat, terminated},
    error::StrContext,
    token::{literal, one_of, take_while},
    PResult, Parser,
};

use self::directive::COMMENT_PREFIX;

#[derive(thiserror::Error, Debug)]
#[error("failed to parse the input: \n{0}")]
pub struct ParseLedgerError(String);

/// Parses the whole ledger file.
pub fn parse_ledger(input: &str) -> Result<Vec<repl::LedgerEntry>, ParseLedgerError> {
    preceded(
        repeat::<_, _, (), _, _>(0.., line_ending::<&str, _>),
        repeat(
            0..,
            terminated(
                parse_ledger_entry,
                repeat::<_, _, (), _, _>(0.., line_ending),
            ),
        ),
    )
    .parse(input)
    .map_err(|e| ParseLedgerError(format!("{}", e)))
}

fn parse_ledger_entry(input: &mut &str) -> PResult<repl::LedgerEntry> {
    // TODO: Consider using dispatch
    alt((
        preceded(
            peek(one_of(COMMENT_PREFIX)),
            cut_err(directive::top_comment.map(repl::LedgerEntry::Comment)),
        ),
        preceded(
            peek(literal("account")),
            cut_err(directive::account_declaration.map(repl::LedgerEntry::Account)),
        ),
        preceded(
            peek(literal("apply")),
            cut_err(directive::apply_tag.map(repl::LedgerEntry::ApplyTag)),
        ),
        preceded(
            peek(literal("commodity")),
            cut_err(directive::commodity_declaration.map(repl::LedgerEntry::Commodity)),
        ),
        preceded(
            peek(literal("end")),
            cut_err(directive::end_apply_tag.map(|_| repl::LedgerEntry::EndApplyTag)),
        ),
        preceded(
            peek(literal("include")),
            cut_err(directive::include.map(repl::LedgerEntry::Include)),
        ),
        preceded(
            peek(take_while(1..=1, |c: char| c.is_ascii_digit())),
            cut_err(transaction::transaction.map(repl::LedgerEntry::Txn)),
        ),
        fail.context(StrContext::Label("no matching syntax")),
    ))
    .parse_next(input)
}

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

    use chrono::NaiveDate;
    use indoc::indoc;
    use pretty_assertions::assert_eq;

    #[test]
    fn parse_ledger_skips_empty_lines() {
        let input = "\n\n2022/01/23\n";
        assert_eq!(input.chars().next(), Some('\n'));
        assert_eq!(
            parse_ledger(input).unwrap(),
            vec![repl::LedgerEntry::Txn(repl::Transaction::new(
                NaiveDate::from_ymd_opt(2022, 1, 23).unwrap(),
                "".to_string()
            ))]
        );
    }

    #[test]
    fn parse_ledger_two_contiguous_transactions() {
        let input = indoc! {"
            2024/4/10 Migros
                Expenses:Grocery
            2024/4/20 Coop
                Expenses:Grocery
        "};

        assert_eq!(
            parse_ledger(input).unwrap(),
            vec![
                repl::LedgerEntry::Txn(repl::Transaction {
                    posts: vec![repl::Posting::new("Expenses:Grocery".to_string())],
                    ..repl::Transaction::new(
                        NaiveDate::from_ymd_opt(2024, 4, 10).unwrap(),
                        "Migros".to_string(),
                    )
                }),
                repl::LedgerEntry::Txn(repl::Transaction {
                    posts: vec![repl::Posting::new("Expenses:Grocery".to_string())],
                    ..repl::Transaction::new(
                        NaiveDate::from_ymd_opt(2024, 4, 20).unwrap(),
                        "Coop".to_string(),
                    )
                })
            ]
        )
    }
}