Implements the ECMA402 trait for Intl.DateTimeFormat.

ecma402_traits/src/datetimeformat.rs

@@ -0,0 +1,281 @@
+// Copyright 2020 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+/// Contains the API configuration as prescribed by ECMA 402.
+///
+/// The meaning of the options is the same as in the similarly named
+/// options in the JS version.
+///
+/// See [DateTimeFormatOptions] for the contents of the options.  See the [DateTimeFormat::try_new]
+/// for the use of the options.
+pub mod options {
+    /// The date and time formatting options.
+    #[derive(Eq, PartialEq, Debug, Clone)]
+    pub enum Style {
+        /// Full length format style.
+        ///
+        /// * Date: "Wednesday, December 19, 2012"
+        /// * Time: "7:00:00 PM Pacific Standard Time"
+        Full,
+        /// Long length format style.
+        ///
+        /// * Date: "December 19, 2012"
+        /// * Time: "7:00:00 PM PST"
+        Long,
+        /// Medium length format style.
+        ///
+        /// * Date: "Dec 19, 2012"
+        /// * Time: "7:00:00 PM"
+        Medium,
+        /// Short length format style.
+        ///
+        /// * Date: "12/29/12"
+        /// * "7:00 PM"
+        Short,
+    }
+
+    /// Controls the calendar to use.
+    ///
+    /// Possible values include: "buddhist", "chinese", " coptic", "ethiopia", "ethiopic",
+    /// "gregory", " hebrew", "indian", "islamic", "iso8601", " japanese", "persian", "roc".
+    ///
+    /// The value entered as currency is not validated.  This responsibility is
+    /// delegated to the implementor.
+    #[derive(Eq, PartialEq, Debug, Clone)]
+    pub struct Calendar(pub String);
+
+    impl Default for Calendar {
+        fn default() -> Self {
+            Self("gregory".into())
+        }
+    }
+
+    impl From<&str> for Calendar {
+        fn from(s: &str) -> Self {
+            Self(s.to_string())
+        }
+    }
+
+    /// The way day periods (morning, afternoon) should be expressed.
+    #[derive(Eq, PartialEq, Debug, Clone)]
+    pub enum DayPeriod {
+        /// "AM", "PM"
+        Narrow,
+        /// "A.M.", "P.M".
+        Short,
+        /// "Morning", "Afternoon".
+        Long,
+    }
+
+    /// Controls the number formatting.
+    ///
+    /// Possible values include: "arab", "arabext", " bali", "beng", "deva", "fullwide", "gujr",
+    /// "guru", "hanidec", "khmr", " knda", "laoo", "latn", "limb", "mlym", " mong", "mymr",
+    /// "orya", "tamldec", " telu", "thai", "tibt".
+    ///
+    /// The value entered is not validated.  This responsibility is delegated to the implementor.
+    #[derive(Eq, PartialEq, Debug, Clone)]
+    pub struct NumberingSystem(pub String);
+
+    impl From<&str> for NumberingSystem {
+        fn from(s: &str) -> Self {
+            Self(s.to_string())
+        }
+    }
+
+    impl Default for NumberingSystem {
+        fn default() -> Self {
+            Self("latn".to_string())
+        }
+    }
+
+    /// Controls the time zone formatting.
+    ///
+    /// The value entered is not validated.  This responsibility is delegated to the implementor.
+    #[derive(Eq, PartialEq, Debug, Clone)]
+    pub struct TimeZone(pub String);
+
+    impl From<&str> for TimeZone {
+        fn from(s: &str) -> Self {
+            Self(s.to_string())
+        }
+    }
+
+    impl Default for TimeZone {
+        fn default() -> Self {
+            Self("UTC".to_string())
+        }
+    }
+
+    /// The hour cycle to use
+    #[derive(Eq, PartialEq, Debug, Clone)]
+    pub enum HourCycle {
+        /// 12 hour cycle, 0..11.
+        H11,
+        /// 12 hour cycle, 1..12.
+        H12,
+        /// 4 hour cycle, 0..23.
+        H23,
+        /// 4 hour cycle, 1..24.
+        H24
+    }
+
+    #[derive(Eq, PartialEq, Debug, Clone)]
+    pub enum Weekday {
+        /// "Thursday"
+        Long,
+        /// "Thu",
+        Short,
+        /// "T",
+        Narrow,
+    }
+
+    #[derive(Eq, PartialEq, Debug, Clone)]
+    pub enum Era {
+        /// "Anno Domini"
+        Long,
+        /// "AD",
+        Short,
+        /// "A",
+        Narrow,
+    }
+
+    #[derive(Eq, PartialEq, Debug, Clone)]
+    pub enum DisplaySize {
+        /// "2012"
+        Numeric,
+        /// "12"
+        TwoDigit,
+    }
+
+    #[derive(Eq, PartialEq, Debug, Clone)]
+    pub enum Month {
+        /// "3"
+        Numeric,
+        /// "03",
+        TwoDigit,
+        /// "March",
+        Long,
+        /// "Mar"
+        Short,
+        /// "M"
+        Narrow,
+    }
+
+    /// The time zone name styling to use.
+    #[derive(Eq, PartialEq, Debug, Clone)]
+    pub enum TimeZoneStyle {
+        /// "British Summer Time"
+        Long,
+        /// "GMT+1"
+        Short,
+    }
+}
+
+#[derive(Eq, PartialEq, Debug, Clone)]
+pub struct DateTimeFormatOptions {
+    /// The formatting style to use for formatting the date part.
+    pub date_style: options::Style,
+    /// The formatting style to use for formatting the time part.
+    pub time_style: options::Style,
+    /// The number of fractional seconds to apply when calling `format`.
+    /// Valid values are 0 to 3.
+    pub fractional_second_digits: u8,
+    /// If left unspecified, the locale default is used.
+    pub calendar: Option<options::Calendar>,
+    /// If left unspecified, the locale default is used.
+    pub day_period: Option<options::DayPeriod>,
+    /// If left unspecified, the locale default is used.
+    pub numbering_system: Option<options::NumberingSystem>,
+    /// If left unspecified, the locale default is used.
+    pub time_zone: Option<options::TimeZone>,
+    /// If left unspecified, the locale default is used.
+    pub hour_cycle: Option<options::HourCycle>,
+    /// If left unspecified, the locale default is used.
+    pub weekday: Option<options::Weekday>,
+    /// If left unspecified, the locale default is used.
+    pub era: Option<options::Era>,
+    /// If left unspecified, the locale default is used.
+    pub year: Option<options::DisplaySize>,
+    /// If left unspecified, the locale default is used.
+    pub month: Option<options::Month>,
+    /// If left unspecified, the locale default is used.
+    pub day: Option<options::DisplaySize>,
+    /// If left unspecified, the locale default is used.
+    pub hour: Option<options::DisplaySize>,
+    /// If left unspecified, the locale default is used.
+    pub minute: Option<options::DisplaySize>,
+    /// If left unspecified, the locale default is used.
+    pub second: Option<options::DisplaySize>,
+    /// If left unspecified, the locale default is used.
+    pub time_zone_style: Option<options::TimeZoneStyle>,
+}
+
+impl Default for DateTimeFormatOptions {
+    fn default() -> Self {
+        Self{
+            date_style: options::Style::Long,
+            time_style: options::Style::Long,
+            fractional_second_digits: 2,
+            day_period: None,
+            numbering_system: None,
+            calendar: None,
+            time_zone: None,
+            hour_cycle: None,
+            weekday: None,
+            era: None,
+            year: None,
+            month: None,
+            day: None,
+            hour: None,
+            minute: None,
+            second: None,
+            time_zone_style: None,
+        }
+    }
+}
+
+use std::fmt;
+
+pub trait DateTimeFormat {
+    /// The type of error reported, if any.
+    type Error: std::error::Error;
+
+    /// Creates a new [DateTimeFormat].
+    ///
+    /// Creation may fail, for example, if the locale-specific data is not loaded, or if
+    /// the supplied options are inconsistent.
+    fn try_new<L>(l: L, opts: DateTimeFormatOptions) -> Result<Self, Self::Error>
+    where
+        L: crate::Locale,
+        Self: Sized;
+
+    /// Formats `date` into the supplied standard `writer` [fmt::Write].
+    ///
+    /// The original [ECMA 402 function][ecma402fmt] returns a string.  This is likely the only
+    /// reasonably generic option in JavaScript so it is adequate.  In Rust, however, it is
+    /// possible to pass in a standard formatting strategy (through `writer`).
+    ///
+    ///   [ecma402fmt]:
+    ///   https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/DateTimeFormat/format
+    ///
+    /// The `date` holds the number of seconds (with fractional part) since the beginning of the
+    /// Unix epoch.  The date is a very generic type because there is no official date-time type
+    /// in Rust.
+    fn format<I, D, W>(&self, date: D, writer: &mut W) -> fmt::Result
+    where
+        I: fmt::Display,
+        D: AsRef<f64>,
+        W: fmt::Write;
+}

ecma402_traits/src/lib.rs

@@ -43,3 +43,8 @@ pub mod numberformat;
 ///
 /// The [collator] mod contains all the needed implementation bits for `Intl.Collator`.
 pub mod collator;
+
+/// A Rust implementation of ECMA 402 DateTimeFormat API.
+///
+/// The [datetimeformat] mod contains all the needed implementation bits for `Intl.DateTimeFormat`.
+pub mod datetimeformat;