Components bag support with only skeleton matching (#587)

components/datetime/src/error.rs

@@ -3,6 +3,7 @@
 // (online at: https://github.com/unicode-org/icu4x/blob/main/LICENSE ).
 
 use crate::pattern;
+use crate::skeleton::SkeletonError;
 use icu_provider::prelude::DataError;
 
 /// A list of possible error outcomes for the [`DateTimeFormat`](crate::DateTimeFormat) struct.
@@ -18,6 +19,8 @@ pub enum DateTimeFormatError {
     /// Missing field in date time input
     /// TODO: How can we return which field was missing?
     MissingInputField,
+    /// An error from skeleton matching,
+    Skeleton(SkeletonError),
 }
 
 impl From<DataError> for DateTimeFormatError {

components/datetime/src/fields/mod.rs

@@ -37,6 +37,21 @@ pub struct Field {
     pub length: FieldLength,
 }
 
+impl Field {
+    pub fn get_length_type(&self) -> TextOrNumeric {
+        match self.symbol {
+            FieldSymbol::Year(year) => year.get_length_type(&self.length),
+            FieldSymbol::Month(month) => month.get_length_type(&self.length),
+            FieldSymbol::Day(day) => day.get_length_type(&self.length),
+            FieldSymbol::Weekday(weekday) => weekday.get_length_type(&self.length),
+            FieldSymbol::DayPeriod(day_period) => day_period.get_length_type(&self.length),
+            FieldSymbol::Hour(hour) => hour.get_length_type(&self.length),
+            FieldSymbol::Minute => TextOrNumeric::Numeric,
+            FieldSymbol::Second(second) => second.get_length_type(&self.length),
+        }
+    }
+}
+
 impl From<(FieldSymbol, FieldLength)> for Field {
     fn from(input: (FieldSymbol, FieldLength)) -> Self {
         Self {

components/datetime/src/fields/symbols.rs

@@ -2,6 +2,7 @@
 // called LICENSE at the top level of the ICU4X source tree
 // (online at: https://github.com/unicode-org/icu4x/blob/main/LICENSE ).
 
+use crate::fields::FieldLength;
 use std::{cmp::Ordering, convert::TryFrom};
 
 #[derive(Debug, PartialEq)]
@@ -28,6 +29,18 @@ pub enum FieldSymbol {
     Second(Second),
 }
 
+#[derive(Debug, Eq, PartialEq, Clone, Copy)]
+pub enum TextOrNumeric {
+    Text,
+    Numeric,
+}
+
+/// FieldSymbols can be either text or numeric. This categorization is important when matching
+/// skeletons with a components::Bag.
+pub trait LengthType {
+    fn get_length_type(&self, length: &FieldLength) -> TextOrNumeric;
+}
+
 impl FieldSymbol {
     /// Skeletons are a Vec<Field>, and represent the Fields that can be used to match to a
     /// specific pattern. The order of the Vec does not affect the Pattern that is output.
@@ -158,6 +171,12 @@ pub enum Year {
     WeekOf,
 }
 
+impl LengthType for Year {
+    fn get_length_type(&self, _length: &FieldLength) -> TextOrNumeric {
+        TextOrNumeric::Numeric
+    }
+}
+
 impl TryFrom<u8> for Year {
     type Error = SymbolError;
     fn try_from(b: u8) -> Result<Self, Self::Error> {
@@ -185,6 +204,19 @@ pub enum Month {
     StandAlone,
 }
 
+impl LengthType for Month {
+    fn get_length_type(&self, length: &FieldLength) -> TextOrNumeric {
+        match length {
+            FieldLength::One => TextOrNumeric::Numeric,
+            FieldLength::TwoDigit => TextOrNumeric::Numeric,
+            FieldLength::Abbreviated => TextOrNumeric::Text,
+            FieldLength::Wide => TextOrNumeric::Text,
+            FieldLength::Narrow => TextOrNumeric::Text,
+            FieldLength::Six => TextOrNumeric::Text,
+        }
+    }
+}
+
 impl TryFrom<u8> for Month {
     type Error = SymbolError;
     fn try_from(b: u8) -> Result<Self, Self::Error> {
@@ -214,6 +246,12 @@ pub enum Day {
     ModifiedJulianDay,
 }
 
+impl LengthType for Day {
+    fn get_length_type(&self, _length: &FieldLength) -> TextOrNumeric {
+        TextOrNumeric::Numeric
+    }
+}
+
 impl TryFrom<u8> for Day {
     type Error = SymbolError;
     fn try_from(b: u8) -> Result<Self, Self::Error> {
@@ -245,6 +283,12 @@ pub enum Hour {
     H24,
 }
 
+impl LengthType for Hour {
+    fn get_length_type(&self, _length: &FieldLength) -> TextOrNumeric {
+        TextOrNumeric::Numeric
+    }
+}
+
 impl TryFrom<u8> for Hour {
     type Error = SymbolError;
     fn try_from(b: u8) -> Result<Self, Self::Error> {
@@ -275,6 +319,12 @@ pub enum Second {
     Millisecond,
 }
 
+impl LengthType for Second {
+    fn get_length_type(&self, _length: &FieldLength) -> TextOrNumeric {
+        TextOrNumeric::Numeric
+    }
+}
+
 impl TryFrom<u8> for Second {
     type Error = SymbolError;
     fn try_from(b: u8) -> Result<Self, Self::Error> {
@@ -304,6 +354,18 @@ pub enum Weekday {
     StandAlone,
 }
 
+impl LengthType for Weekday {
+    fn get_length_type(&self, length: &FieldLength) -> TextOrNumeric {
+        match self {
+            Weekday::Format => TextOrNumeric::Text,
+            Weekday::Local | Weekday::StandAlone => match length {
+                FieldLength::One | FieldLength::TwoDigit => TextOrNumeric::Text,
+                _ => TextOrNumeric::Numeric,
+            },
+        }
+    }
+}
+
 impl TryFrom<u8> for Weekday {
     type Error = SymbolError;
     fn try_from(b: u8) -> Result<Self, Self::Error> {
@@ -332,6 +394,12 @@ pub enum DayPeriod {
     NoonMidnight,
 }
 
+impl LengthType for DayPeriod {
+    fn get_length_type(&self, _length: &FieldLength) -> TextOrNumeric {
+        TextOrNumeric::Text
+    }
+}
+
 impl TryFrom<u8> for DayPeriod {
     type Error = SymbolError;
     fn try_from(b: u8) -> Result<Self, Self::Error> {