time_macros/format_description/
mod.rs

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1//! Parser for format descriptions.
2
3macro_rules! version {
4    ($range:expr) => {
5        $range.contains(&VERSION)
6    };
7}
8
9mod ast;
10mod format_item;
11mod lexer;
12mod public;
13
14pub(crate) fn parse_with_version(
15    version: Option<crate::FormatDescriptionVersion>,
16    s: &[u8],
17    proc_span: proc_macro::Span,
18) -> Result<Vec<public::OwnedFormatItem>, crate::Error> {
19    match version {
20        Some(crate::FormatDescriptionVersion::V1) | None => parse::<1>(s, proc_span),
21        Some(crate::FormatDescriptionVersion::V2) => parse::<2>(s, proc_span),
22    }
23}
24
25fn parse<const VERSION: u8>(
26    s: &[u8],
27    proc_span: proc_macro::Span,
28) -> Result<Vec<public::OwnedFormatItem>, crate::Error> {
29    let mut lexed = lexer::lex::<VERSION>(s, proc_span);
30    let ast = ast::parse::<_, VERSION>(&mut lexed);
31    let format_items = format_item::parse(ast);
32    Ok(format_items
33        .map(|res| res.map(Into::into))
34        .collect::<Result<_, _>>()?)
35}
36
37#[derive(Clone, Copy)]
38struct Location {
39    byte: u32,
40    proc_span: proc_macro::Span,
41}
42
43impl Location {
44    fn to(self, end: Self) -> Span {
45        Span { start: self, end }
46    }
47
48    #[must_use = "this does not modify the original value"]
49    fn offset(&self, offset: u32) -> Self {
50        Self {
51            byte: self.byte + offset,
52            proc_span: self.proc_span,
53        }
54    }
55
56    fn error(self, message: &'static str) -> Error {
57        Error {
58            message,
59            _span: unused(Span {
60                start: self,
61                end: self,
62            }),
63            proc_span: self.proc_span,
64        }
65    }
66}
67
68#[derive(Clone, Copy)]
69struct Span {
70    #[allow(clippy::missing_docs_in_private_items)]
71    start: Location,
72    #[allow(clippy::missing_docs_in_private_items)]
73    end: Location,
74}
75
76impl Span {
77    #[must_use = "this does not modify the original value"]
78    const fn shrink_to_start(&self) -> Self {
79        Self {
80            start: self.start,
81            end: self.start,
82        }
83    }
84
85    #[must_use = "this does not modify the original value"]
86    const fn shrink_to_end(&self) -> Self {
87        Self {
88            start: self.end,
89            end: self.end,
90        }
91    }
92
93    #[must_use = "this does not modify the original value"]
94    const fn shrink_to_before(&self, pos: u32) -> Self {
95        Self {
96            start: self.start,
97            end: Location {
98                byte: self.start.byte + pos - 1,
99                proc_span: self.start.proc_span,
100            },
101        }
102    }
103
104    #[must_use = "this does not modify the original value"]
105    fn shrink_to_after(&self, pos: u32) -> Self {
106        Self {
107            start: Location {
108                byte: self.start.byte + pos + 1,
109                proc_span: self.start.proc_span,
110            },
111            end: self.end,
112        }
113    }
114
115    fn error(self, message: &'static str) -> Error {
116        Error {
117            message,
118            _span: unused(self),
119            proc_span: self.start.proc_span,
120        }
121    }
122}
123
124#[derive(Clone, Copy)]
125struct Spanned<T> {
126    value: T,
127    span: Span,
128}
129
130impl<T> core::ops::Deref for Spanned<T> {
131    type Target = T;
132
133    fn deref(&self) -> &Self::Target {
134        &self.value
135    }
136}
137
138trait SpannedValue: Sized {
139    fn spanned(self, span: Span) -> Spanned<Self>;
140}
141
142impl<T> SpannedValue for T {
143    fn spanned(self, span: Span) -> Spanned<Self> {
144        Spanned { value: self, span }
145    }
146}
147
148struct Error {
149    message: &'static str,
150    _span: Unused<Span>,
151    proc_span: proc_macro::Span,
152}
153
154impl From<Error> for crate::Error {
155    fn from(error: Error) -> Self {
156        Self::Custom {
157            message: error.message.into(),
158            span_start: Some(error.proc_span),
159            span_end: Some(error.proc_span),
160        }
161    }
162}
163
164struct Unused<T>(core::marker::PhantomData<T>);
165
166#[allow(clippy::missing_const_for_fn)] // false positive
167fn unused<T>(_: T) -> Unused<T> {
168    Unused(core::marker::PhantomData)
169}
time_macros/format_description/mod.rs

time_macros/format_description/
mod.rs
