icu_locale_core/
macros.rs

1// This file is part of ICU4X. For terms of use, please see the file
2// called LICENSE at the top level of the ICU4X source tree
3// (online at: https://github.com/unicode-org/icu4x/blob/main/LICENSE ).
4
5/// A macro allowing for compile-time construction of valid [`LanguageIdentifier`]s.
6///
7/// The macro will perform syntax normalization of the tag.
8///
9/// # Examples
10///
11/// ```
12/// use icu::locale::{langid, LanguageIdentifier};
13///
14/// const DE_AT: LanguageIdentifier = langid!("de-at");
15///
16/// let de_at: LanguageIdentifier = "de-at".parse().unwrap();
17///
18/// assert_eq!(DE_AT, de_at);
19/// ```
20///
21/// *Note*: The macro cannot produce language identifiers with more than one variants due to const
22/// limitations (see [`Heap Allocations in Constants`]):
23///
24/// ```compile_fail,E0080
25/// icu::locale::langid!("und-variant1-variant2");
26/// ```
27///
28/// Use runtime parsing instead:
29/// ```
30/// "und-variant1-variant2"
31///     .parse::<icu::locale::LanguageIdentifier>()
32///     .unwrap();
33/// ```
34///
35/// [`LanguageIdentifier`]: crate::LanguageIdentifier
36/// [`Heap Allocations in Constants`]: https://github.com/rust-lang/const-eval/issues/20
37#[macro_export]
38macro_rules! langid {
39    ($langid:literal) => { const {
40        match $crate::LanguageIdentifier::try_from_utf8_with_single_variant($langid.as_bytes()) {
41            Ok((language, script, region, variant)) => $crate::LanguageIdentifier {
42                language,
43                script,
44                region,
45                variants: match variant {
46                    Some(v) => $crate::subtags::Variants::from_variant(v),
47                    None => $crate::subtags::Variants::new(),
48                }
49            },
50            _ => panic!(concat!("Invalid language code: ", $langid, " . Note langid! macro can only support up to a single variant tag. Use runtime parsing instead.")),
51        }
52    }};
53}
54
55/// A macro allowing for compile-time construction of valid [`Locale`]s.
56///
57/// The macro will perform syntax normalization of the tag.
58///
59/// # Examples
60///
61/// ```
62/// use icu::locale::{locale, Locale};
63///
64/// const DE_AT: Locale = locale!("de-at");
65///
66/// let de_at: Locale = "de-at".parse().unwrap();
67///
68/// assert_eq!(DE_AT, de_at);
69/// ```
70///
71/// *Note*: The macro cannot produce locales with more than one variant or multiple extensions
72/// (only single keyword unicode extension is supported) due to const
73/// limitations (see [`Heap Allocations in Constants`]):
74///
75/// ```compile_fail,E0080
76/// icu::locale::locale!("sl-IT-rozaj-biske-1994");
77/// ```
78/// Use runtime parsing instead:
79/// ```
80/// "sl-IT-rozaj-biske-1994"
81///     .parse::<icu::locale::Locale>()
82///     .unwrap();
83/// ```
84///
85/// Locales with multiple keys are not supported
86/// ```compile_fail,E0080
87/// icu::locale::locale!("th-TH-u-ca-buddhist-nu-thai");
88/// ```
89/// Use runtime parsing instead:
90/// ```
91/// "th-TH-u-ca-buddhist-nu-thai"
92///     .parse::<icu::locale::Locale>()
93///     .unwrap();
94/// ```
95///
96/// Locales with attributes are not supported
97/// ```compile_fail,E0080
98/// icu::locale::locale!("en-US-u-foobar-ca-buddhist");
99/// ```
100/// Use runtime parsing instead:
101/// ```
102/// "en-US-u-foobar-ca-buddhist"
103///     .parse::<icu::locale::Locale>()
104///     .unwrap();
105/// ```
106///
107/// Locales with single key but multiple types are not supported
108/// ```compile_fail,E0080
109/// icu::locale::locale!("en-US-u-ca-islamic-umalqura");
110/// ```
111/// Use runtime parsing instead:
112/// ```
113/// "en-US-u-ca-islamic-umalqura"
114///     .parse::<icu::locale::Locale>()
115///     .unwrap();
116/// ```
117/// [`Locale`]: crate::Locale
118/// [`Heap Allocations in Constants`]: https://github.com/rust-lang/const-eval/issues/20
119#[macro_export]
120macro_rules! locale {
121    ($locale:literal) => { const {
122        match $crate::Locale::try_from_utf8_with_single_variant_single_keyword_unicode_extension(
123            $locale.as_bytes(),
124        ) {
125            Ok((language, script, region, variant, keyword)) => $crate::Locale {
126                id: $crate::LanguageIdentifier {
127                    language,
128                    script,
129                    region,
130                    variants: match variant {
131                        Some(v) => $crate::subtags::Variants::from_variant(v),
132                        None => $crate::subtags::Variants::new(),
133                    },
134                },
135                extensions: match keyword {
136                    Some(k) => $crate::extensions::Extensions::from_unicode(
137                        $crate::extensions::unicode::Unicode {
138                            keywords: $crate::extensions::unicode::Keywords::new_single(
139                                k.0,
140                                $crate::extensions::unicode::Value::from_subtag(k.1),
141                            ),
142
143                            attributes: $crate::extensions::unicode::Attributes::new(),
144                        },
145                    ),
146                    None => $crate::extensions::Extensions::new(),
147                },
148            },
149            _ => panic!(concat!(
150                "Invalid language code: ",
151                $locale,
152                " . Note the locale! macro only supports up to one variant tag; \
153                                    and one unicode keyword, other extension are \
154                                    not supported. Use runtime parsing instead."
155            )),
156        }
157    }};
158}
159
160#[cfg(test)]
161mod test {
162    use crate::LanguageIdentifier;
163    use crate::Locale;
164
165    #[test]
166    fn test_langid_macro_can_parse_langid_with_single_variant() {
167        const DE_AT_FOOBAR: LanguageIdentifier = langid!("de-at-foobar");
168        let de_at_foobar: LanguageIdentifier = "de-at-foobar".parse().unwrap();
169        assert_eq!(DE_AT_FOOBAR, de_at_foobar);
170    }
171
172    #[test]
173    fn test_locale_macro_can_parse_locale_with_single_variant() {
174        const DE_AT_FOOBAR: Locale = locale!("de-at-foobar");
175        let de_at_foobar: Locale = "de-at-foobar".parse().unwrap();
176        assert_eq!(DE_AT_FOOBAR, de_at_foobar);
177    }
178
179    #[test]
180    fn test_locale_macro_can_parse_locale_with_single_keyword_unicode_extension() {
181        const DE_AT_U_CA_FOOBAR: Locale = locale!("de-at-u-ca-foobar");
182        let de_at_u_ca_foobar: Locale = "de-at-u-ca-foobar".parse().unwrap();
183        assert_eq!(DE_AT_U_CA_FOOBAR, de_at_u_ca_foobar);
184    }
185}
icu_locale_core/macros.rs

icu_locale_core/
macros.rs
