Locales and format_localized (chronotope#453)

AUTHORS.txt

@@ -8,6 +8,7 @@ Ben Boeckel <[email protected]>
 Ben Eills <[email protected]>
 Brandon W Maister <[email protected]>
 Brandon W Maister <[email protected]>
+Cecile Tonglet <[email protected]>
 Colin Ray <[email protected]>
 Corey Farwell <[email protected]>
 Dan <[email protected]>

CHANGELOG.md

@@ -14,6 +14,7 @@ Versions with only mechanical changes will be omitted from the following list.
 
 * Add day and week iterators for `NaiveDate` (@gnzlbg & @robyoung)
 * Add a `Month` enum (@hhamana)
+* Add `locales`. All format functions can now use locales.
 
 ### Improvements
 

Cargo.toml

@@ -29,6 +29,7 @@ alloc = []
 std = []
 clock = ["time", "std"]
 wasmbind = ["wasm-bindgen", "js-sys"]
+unstable-locales = ["pure-rust-locales", "alloc"]
 __internal_bench = []
 __doctest = []
 
@@ -38,6 +39,7 @@ num-integer = { version = "0.1.36", default-features = false }
 num-traits = { version = "0.2", default-features = false }
 rustc-serialize = { version = "0.3.20", optional = true }
 serde = { version = "1.0.99", default-features = false, optional = true }
+pure-rust-locales = { version = "0.5.2", optional = true }
 
 [target.'cfg(all(target_arch = "wasm32", not(any(target_os = "emscripten", target_os = "wasi"))))'.dependencies]
 wasm-bindgen = { version = "0.2", optional = true }

README.md

@@ -61,7 +61,10 @@ Default features:
 Optional features:
 
 - `wasmbind`: Enable integration with [wasm-bindgen][] and its `js-sys` project
-- [`serde`][]: Enable
+- [`serde`][]: Enable serialization/deserialization via serde.
+- `unstable-locales`: Enable localization. This adds various methods with a
+  `_localized` suffix. The implementation and API may change or even be
+  removed in a patch release. Feedback welcome.
 
 [`serde`]: https://github.com/serde-rs/serde
 [wasm-bindgen]: https://github.com/rustwasm/wasm-bindgen
@@ -225,12 +228,23 @@ Chrono also provides [`to_rfc2822`](https://docs.rs/chrono/0.4/chrono/struct.Dat
 [`to_rfc3339`](https://docs.rs/chrono/0.4/chrono/struct.DateTime.html#method.to_rfc3339) methods
 for well-known formats.
 
+Chrono now also provides date formatting in almost any language without the
+help of an additional C library. This functionality is under the feature
+`unstable-locales`:
+
+```text
+chrono { version = "0.4", features = ["unstable-locales"]
+```
+
+The `unstable-locales` feature requires and implies at least the `alloc` feature.
+
 ```rust
 use chrono::prelude::*;
 
 let dt = Utc.ymd(2014, 11, 28).and_hms(12, 0, 9);
 assert_eq!(dt.format("%Y-%m-%d %H:%M:%S").to_string(), "2014-11-28 12:00:09");
 assert_eq!(dt.format("%a %b %e %T %Y").to_string(), "Fri Nov 28 12:00:09 2014");
+assert_eq!(dt.format_localized("%A %e %B %Y, %T", Locale::fr_BE).to_string(), "vendredi 28 novembre 2014, 12:00:09");
 assert_eq!(dt.format("%a %b %e %T %Y").to_string(), dt.format("%c").to_string());
 
 assert_eq!(dt.to_string(), "2014-11-28 12:00:09 UTC");

ci/github.sh

@@ -6,7 +6,7 @@ set -euo pipefail
 source "${BASH_SOURCE[0]%/*}/_shlib.sh"
 
 TEST_TZS=(ACST-9:30 EST4 UTC0 Asia/Katmandu)
-FEATURES=(std serde clock "alloc serde")
+FEATURES=(std serde clock "alloc serde" unstable-locales)
 RUST_113_FEATURES=(rustc-serialize serde)
 
 main() {
@@ -56,7 +56,7 @@ test_all_tzs() {
 test_regular() {
     tz="$1" && shift
 
-    runt env TZ="$tz" cargo test --features __doctest --color=always -- --color=always
+    runt env TZ="$tz" cargo test --features __doctest,unstable-locales --color=always -- --color=always
     for feature in "${FEATURES[@]}"; do
         runt env TZ="$tz" cargo test --no-default-features --features "$feature" --lib --color=always -- --color=always
     done

src/date.rs

@@ -10,6 +10,8 @@ use core::ops::{Add, Sub};
 use core::{fmt, hash};
 use oldtime::Duration as OldDuration;
 
+#[cfg(feature = "unstable-locales")]
+use format::Locale;
 #[cfg(any(feature = "alloc", feature = "std", test))]
 use format::{DelayedFormat, Item, StrftimeItems};
 use naive::{self, IsoWeek, NaiveDate, NaiveTime};
@@ -295,6 +297,40 @@ where
     pub fn format<'a>(&self, fmt: &'a str) -> DelayedFormat<StrftimeItems<'a>> {
         self.format_with_items(StrftimeItems::new(fmt))
     }
+
+    /// Formats the date with the specified formatting items and locale.
+    #[cfg(feature = "unstable-locales")]
+    #[inline]
+    pub fn format_localized_with_items<'a, I, B>(
+        &self,
+        items: I,
+        locale: Locale,
+    ) -> DelayedFormat<I>
+    where
+        I: Iterator<Item = B> + Clone,
+        B: Borrow<Item<'a>>,
+    {
+        DelayedFormat::new_with_offset_and_locale(
+            Some(self.naive_local()),
+            None,
+            &self.offset,
+            items,
+            locale,
+        )
+    }
+
+    /// Formats the date with the specified format string and locale.
+    /// See the [`format::strftime` module](./format/strftime/index.html)
+    /// on the supported escape sequences.
+    #[cfg(feature = "unstable-locales")]
+    #[inline]
+    pub fn format_localized<'a>(
+        &self,
+        fmt: &'a str,
+        locale: Locale,
+    ) -> DelayedFormat<StrftimeItems<'a>> {
+        self.format_localized_with_items(StrftimeItems::new_with_locale(fmt, locale), locale)
+    }
 }
 
 impl<Tz: TimeZone> Datelike for Date<Tz> {

src/datetime.rs

@@ -19,6 +19,8 @@ use std::string::ToString;
 use core::borrow::Borrow;
 #[cfg(any(feature = "alloc", feature = "std", test))]
 use format::DelayedFormat;
+#[cfg(feature = "unstable-locales")]
+use format::Locale;
 use format::{parse, ParseError, ParseResult, Parsed, StrftimeItems};
 use format::{Fixed, Item};
 use naive::{self, IsoWeek, NaiveDateTime, NaiveTime};
@@ -493,6 +495,41 @@ where
     pub fn format<'a>(&self, fmt: &'a str) -> DelayedFormat<StrftimeItems<'a>> {
         self.format_with_items(StrftimeItems::new(fmt))
     }
+
+    /// Formats the combined date and time with the specified formatting items and locale.
+    #[cfg(feature = "unstable-locales")]
+    #[inline]
+    pub fn format_localized_with_items<'a, I, B>(
+        &self,
+        items: I,
+        locale: Locale,
+    ) -> DelayedFormat<I>
+    where
+        I: Iterator<Item = B> + Clone,
+        B: Borrow<Item<'a>>,
+    {
+        let local = self.naive_local();
+        DelayedFormat::new_with_offset_and_locale(
+            Some(local.date()),
+            Some(local.time()),
+            &self.offset,
+            items,
+            locale,
+        )
+    }
+
+    /// Formats the combined date and time with the specified format string and locale.
+    /// See the [`format::strftime` module](./format/strftime/index.html)
+    /// on the supported escape sequences.
+    #[cfg(feature = "unstable-locales")]
+    #[inline]
+    pub fn format_localized<'a>(
+        &self,
+        fmt: &'a str,
+        locale: Locale,
+    ) -> DelayedFormat<StrftimeItems<'a>> {
+        self.format_localized_with_items(StrftimeItems::new_with_locale(fmt, locale), locale)
+    }
 }
 
 impl<Tz: TimeZone> Datelike for DateTime<Tz> {

src/format/locales.rs

@@ -0,0 +1,33 @@
+use pure_rust_locales::{locale_match, Locale};
+
+pub(crate) fn short_months(locale: Locale) -> &'static [&'static str] {
+    locale_match!(locale => LC_TIME::ABMON)
+}
+
+pub(crate) fn long_months(locale: Locale) -> &'static [&'static str] {
+    locale_match!(locale => LC_TIME::MON)
+}
+
+pub(crate) fn short_weekdays(locale: Locale) -> &'static [&'static str] {
+    locale_match!(locale => LC_TIME::ABDAY)
+}
+
+pub(crate) fn long_weekdays(locale: Locale) -> &'static [&'static str] {
+    locale_match!(locale => LC_TIME::DAY)
+}
+
+pub(crate) fn am_pm(locale: Locale) -> &'static [&'static str] {
+    locale_match!(locale => LC_TIME::AM_PM)
+}
+
+pub(crate) fn d_fmt(locale: Locale) -> &'static str {
+    locale_match!(locale => LC_TIME::D_FMT)
+}
+
+pub(crate) fn d_t_fmt(locale: Locale) -> &'static str {
+    locale_match!(locale => LC_TIME::D_T_FMT)
+}
+
+pub(crate) fn t_fmt(locale: Locale) -> &'static str {
+    locale_match!(locale => LC_TIME::T_FMT)
+}