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: Lexed> = lexer::lex::<VERSION>(input:s, proc_span);
30 let ast: impl Iterator> = ast::parse::<_, VERSION>(&mut lexed);
31 let format_items: impl Iterator> = format_item::parse(ast);
32 Ok(format_itemsimpl Iterator>
33 .map(|res: Result, Error>| res.map(op: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}
170