winnow/combinator/
sequence.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
use crate::combinator::trace;
use crate::error::ParserError;
use crate::stream::Stream;
use crate::*;

#[doc(inline)]
pub use crate::seq;

/// Sequence two parsers, only returning the output from the second.
///
/// See also [`seq`] to generalize this across any number of fields.
///
/// # Example
///
/// ```rust
/// # use winnow::{error::ErrMode, error::ErrorKind, error::InputError, error::Needed};
/// # use winnow::prelude::*;
/// # use winnow::error::Needed::Size;
/// use winnow::combinator::preceded;
///
/// let mut parser = preceded("abc", "efg");
///
/// assert_eq!(parser.parse_peek("abcefg"), Ok(("", "efg")));
/// assert_eq!(parser.parse_peek("abcefghij"), Ok(("hij", "efg")));
/// assert_eq!(parser.parse_peek(""), Err(ErrMode::Backtrack(InputError::new("", ErrorKind::Tag))));
/// assert_eq!(parser.parse_peek("123"), Err(ErrMode::Backtrack(InputError::new("123", ErrorKind::Tag))));
/// ```
#[doc(alias = "ignore_then")]
pub fn preceded<Input, Ignored, Output, Error, IgnoredParser, ParseNext>(
    mut ignored: IgnoredParser,
    mut parser: ParseNext,
) -> impl Parser<Input, Output, Error>
where
    Input: Stream,
    Error: ParserError<Input>,
    IgnoredParser: Parser<Input, Ignored, Error>,
    ParseNext: Parser<Input, Output, Error>,
{
    trace("preceded", move |input: &mut Input| {
        let _ = ignored.parse_next(input)?;
        parser.parse_next(input)
    })
}

/// Sequence two parsers, only returning the output of the first.
///
/// See also [`seq`] to generalize this across any number of fields.
///
/// # Example
///
/// ```rust
/// # use winnow::{error::ErrMode, error::ErrorKind, error::InputError, error::Needed};
/// # use winnow::prelude::*;
/// # use winnow::error::Needed::Size;
/// use winnow::combinator::terminated;
///
/// let mut parser = terminated("abc", "efg");
///
/// assert_eq!(parser.parse_peek("abcefg"), Ok(("", "abc")));
/// assert_eq!(parser.parse_peek("abcefghij"), Ok(("hij", "abc")));
/// assert_eq!(parser.parse_peek(""), Err(ErrMode::Backtrack(InputError::new("", ErrorKind::Tag))));
/// assert_eq!(parser.parse_peek("123"), Err(ErrMode::Backtrack(InputError::new("123", ErrorKind::Tag))));
/// ```
#[doc(alias = "then_ignore")]
pub fn terminated<Input, Output, Ignored, Error, ParseNext, IgnoredParser>(
    mut parser: ParseNext,
    mut ignored: IgnoredParser,
) -> impl Parser<Input, Output, Error>
where
    Input: Stream,
    Error: ParserError<Input>,
    ParseNext: Parser<Input, Output, Error>,
    IgnoredParser: Parser<Input, Ignored, Error>,
{
    trace("terminated", move |input: &mut Input| {
        let o = parser.parse_next(input)?;
        ignored.parse_next(input).map(|_| o)
    })
}

/// Sequence three parsers, only returning the values of the first and third.
///
/// See also [`seq`] to generalize this across any number of fields.
///
/// # Example
///
/// ```rust
/// # use winnow::{error::ErrMode, error::ErrorKind, error::InputError, error::Needed};
/// # use winnow::error::Needed::Size;
/// # use winnow::prelude::*;
/// use winnow::combinator::separated_pair;
///
/// let mut parser = separated_pair("abc", "|", "efg");
///
/// assert_eq!(parser.parse_peek("abc|efg"), Ok(("", ("abc", "efg"))));
/// assert_eq!(parser.parse_peek("abc|efghij"), Ok(("hij", ("abc", "efg"))));
/// assert_eq!(parser.parse_peek(""), Err(ErrMode::Backtrack(InputError::new("", ErrorKind::Tag))));
/// assert_eq!(parser.parse_peek("123"), Err(ErrMode::Backtrack(InputError::new("123", ErrorKind::Tag))));
/// ```
pub fn separated_pair<Input, O1, Sep, O2, Error, P1, SepParser, P2>(
    mut first: P1,
    mut sep: SepParser,
    mut second: P2,
) -> impl Parser<Input, (O1, O2), Error>
where
    Input: Stream,
    Error: ParserError<Input>,
    P1: Parser<Input, O1, Error>,
    SepParser: Parser<Input, Sep, Error>,
    P2: Parser<Input, O2, Error>,
{
    trace("separated_pair", move |input: &mut Input| {
        let o1 = first.parse_next(input)?;
        let _ = sep.parse_next(input)?;
        second.parse_next(input).map(|o2| (o1, o2))
    })
}

/// Sequence three parsers, only returning the output of the second.
///
/// See also [`seq`] to generalize this across any number of fields.
///
/// # Example
///
/// ```rust
/// # use winnow::{error::ErrMode, error::ErrorKind, error::InputError, error::Needed};
/// # use winnow::error::Needed::Size;
/// # use winnow::prelude::*;
/// use winnow::combinator::delimited;
///
/// let mut parser = delimited("(", "abc", ")");
///
/// assert_eq!(parser.parse_peek("(abc)"), Ok(("", "abc")));
/// assert_eq!(parser.parse_peek("(abc)def"), Ok(("def", "abc")));
/// assert_eq!(parser.parse_peek(""), Err(ErrMode::Backtrack(InputError::new("", ErrorKind::Tag))));
/// assert_eq!(parser.parse_peek("123"), Err(ErrMode::Backtrack(InputError::new("123", ErrorKind::Tag))));
/// ```
#[doc(alias = "between")]
#[doc(alias = "padded")]
pub fn delimited<
    Input,
    Ignored1,
    Output,
    Ignored2,
    Error,
    IgnoredParser1,
    ParseNext,
    IgnoredParser2,
>(
    mut ignored1: IgnoredParser1,
    mut parser: ParseNext,
    mut ignored2: IgnoredParser2,
) -> impl Parser<Input, Output, Error>
where
    Input: Stream,
    Error: ParserError<Input>,
    IgnoredParser1: Parser<Input, Ignored1, Error>,
    ParseNext: Parser<Input, Output, Error>,
    IgnoredParser2: Parser<Input, Ignored2, Error>,
{
    trace("delimited", move |input: &mut Input| {
        let _ = ignored1.parse_next(input)?;
        let o2 = parser.parse_next(input)?;
        ignored2.parse_next(input).map(|_| o2)
    })
}