pomsky 0.12.0

A new regular expression language
Documentation 
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

use pomsky_syntax::exprs::{Reference, ReferenceTarget};

use crate::{
    compile::{CompileResult, CompileState},
    diagnose::{CompileErrorKind, Feature},
    options::{CompileOptions, RegexFlavor},
    regex::Regex,
};

use super::Compile;

#[derive(Clone, Copy, PartialEq, Eq)]
enum ReferenceDirection {
    Backwards,
    Forwards,
}

impl From<ReferenceDirection> for Feature {
    fn from(direction: ReferenceDirection) -> Self {
        match direction {
            ReferenceDirection::Backwards => Feature::Backreference,
            ReferenceDirection::Forwards => Feature::ForwardReference,
        }
    }
}

impl Compile for Reference {
    fn compile(&self, options: CompileOptions, state: &mut CompileState) -> CompileResult {
        let (direction, number) = match &self.target {
            ReferenceTarget::Named(name) => match state.used_names.get(name) {
                Some(index) => {
                    let direction = if index.absolute >= state.next_idx {
                        ReferenceDirection::Forwards
                    } else {
                        ReferenceDirection::Backwards
                    };
                    let idx = if let RegexFlavor::DotNet = options.flavor {
                        state.numbered_groups_count + index.from_named
                    } else {
                        index.absolute
                    };
                    (direction, idx)
                }
                None => {
                    return Err(CompileErrorKind::UnknownReferenceName {
                        found: name.clone().into(),
                        #[cfg(feature = "suggestions")]
                        similar: pomsky_syntax::find_suggestion(
                            name,
                            state.used_names.keys().map(String::as_str),
                        ),
                    }
                    .at(self.span));
                }
            },
            &ReferenceTarget::Number(idx) => {
                if idx == 0 {
                    return Err(CompileErrorKind::UnknownReferenceNumber(0).at(self.span));
                }

                let direction = if idx > 99 {
                    return Err(CompileErrorKind::HugeReference.at(self.span));
                } else if idx > state.groups_count {
                    return Err(CompileErrorKind::UnknownReferenceNumber(idx as i32).at(self.span));
                } else if idx >= state.next_idx {
                    ReferenceDirection::Forwards
                } else {
                    ReferenceDirection::Backwards
                };

                if options.flavor == RegexFlavor::DotNet
                    && state.has_named_groups()
                    && state.has_numbered_groups()
                {
                    return Err(CompileErrorKind::DotNetNumberedRefWithMixedGroups.at(self.span));
                }

                (direction, idx)
            }
            &ReferenceTarget::Relative(offset) => {
                let direction = if offset >= 0 {
                    ReferenceDirection::Forwards
                } else {
                    ReferenceDirection::Backwards
                };

                let num = match offset {
                    0 => return Err(CompileErrorKind::RelativeRefZero.at(self.span)),
                    i32::MIN..=-1 => offset + (state.next_idx as i32),
                    1..=i32::MAX => offset + (state.next_idx as i32) - 1,
                };
                if num <= 0 || (num as u32) > state.groups_count {
                    return Err(CompileErrorKind::UnknownReferenceNumber(num).at(self.span));
                }

                (direction, num as u32)
            }
        };

        match options.flavor {
            RegexFlavor::Rust | RegexFlavor::RE2 => {
                Err(CompileErrorKind::Unsupported(direction.into(), options.flavor).at(self.span))
            }

            RegexFlavor::JavaScript | RegexFlavor::Python | RegexFlavor::Ruby
                if direction == ReferenceDirection::Forwards =>
            {
                Err(CompileErrorKind::Unsupported(Feature::ForwardReference, options.flavor)
                    .at(self.span))
            }

            _ => Ok(Regex::Reference(match options.flavor {
                RegexFlavor::Ruby => {
                    if let Some(group_name) = state.used_names_vec[number as usize].as_ref() {
                        RegexReference::Name(group_name.clone())
                    } else if !state.has_named_groups() {
                        RegexReference::Number(number)
                    } else {
                        return Err(CompileErrorKind::Unsupported(
                            Feature::MixedReferences,
                            options.flavor,
                        )
                        .at(self.span));
                    }
                }
                _ => RegexReference::Number(number),
            })),
        }
    }
}

#[cfg_attr(feature = "dbg", derive(Debug))]
pub(crate) enum RegexReference {
    Number(u32),
    Name(String),
}

impl RegexReference {
    pub(crate) fn codegen(&self, buf: &mut String) {
        use std::fmt::Write;

        match self {
            &RegexReference::Number(number) => {
                debug_assert!(number <= 99);
                write!(buf, "(?:\\{number})").unwrap();
            }
            RegexReference::Name(name) => {
                write!(buf, "\\k<{name}>").unwrap();
            }
        }
    }
}