Expose IntervalMonthDayNano and IntervalDayTime and update docs

arrow-array/src/array/primitive_array.rs

@@ -351,19 +351,51 @@ pub type Time64MicrosecondArray = PrimitiveArray<Time64MicrosecondType>;
 /// hold values such as `00:02:00.123456789`
 pub type Time64NanosecondArray = PrimitiveArray<Time64NanosecondType>;
 
-/// A [`PrimitiveArray`] of “calendar” intervals in months
+/// A [`PrimitiveArray`] of “calendar” intervals in whole months
 ///
 /// See [`IntervalYearMonthType`] for details on representation and caveats.
+///
+/// # Example
+/// ```
+/// # use arrow_array::IntervalYearMonthArray;
+/// let array = IntervalYearMonthArray::from(vec![
+///   2,  // 2 months
+///   25, // 2 years and 1 month
+///   -1  // -1 months
+/// ]);
+/// ```
 pub type IntervalYearMonthArray = PrimitiveArray<IntervalYearMonthType>;
 
 /// A [`PrimitiveArray`] of “calendar” intervals in days and milliseconds
 ///
-/// See [`IntervalDayTimeType`] for details on representation and caveats.
+/// See [`IntervalDayTime`] for details on representation and caveats.
+///
+/// # Example
+/// ```
+/// # use arrow_array::IntervalDayTimeArray;
+/// use arrow_array::types::IntervalDayTime;
+/// let array = IntervalDayTimeArray::from(vec![
+///   IntervalDayTime::new(1, 1000),                 // 1 day, 1000 milliseconds
+///   IntervalDayTime::new(33, 0),                  // 33 days, 0 milliseconds
+///   IntervalDayTime::new(0, 12 * 60 * 60 * 1000), // 0 days, 12 hours
+/// ]);
+/// ```
 pub type IntervalDayTimeArray = PrimitiveArray<IntervalDayTimeType>;
 
 /// A [`PrimitiveArray`] of “calendar” intervals in  months, days, and nanoseconds.
 ///
-/// See [`IntervalMonthDayNanoType`] for details on representation and caveats.
+/// See [`IntervalMonthDayNano`] for details on representation and caveats.
+///
+/// # Example
+/// ```
+/// # use arrow_array::IntervalMonthDayNanoArray;
+/// use arrow_array::types::IntervalMonthDayNano;
+/// let array = IntervalMonthDayNanoArray::from(vec![
+///   IntervalMonthDayNano::new(1, 2, 1000),             // 1 month, 2 days, 1 nanosecond
+///   IntervalMonthDayNano::new(12, 1, 0),               // 12 months, 1 days, 0 nanoseconds
+///   IntervalMonthDayNano::new(0, 0, 12 * 1000 * 1000), // 0 days, 12 milliseconds
+/// ]);
+/// ```
 pub type IntervalMonthDayNanoArray = PrimitiveArray<IntervalMonthDayNanoType>;
 
 /// A [`PrimitiveArray`] of elapsed durations in seconds

arrow-array/src/types.rs

@@ -23,7 +23,7 @@ use crate::delta::{
 use crate::temporal_conversions::as_datetime_with_timezone;
 use crate::timezone::Tz;
 use crate::{ArrowNativeTypeOp, OffsetSizeTrait};
-use arrow_buffer::{i256, Buffer, IntervalDayTime, IntervalMonthDayNano, OffsetBuffer};
+use arrow_buffer::{i256, Buffer, OffsetBuffer};
 use arrow_data::decimal::{validate_decimal256_precision, validate_decimal_precision};
 use arrow_data::{validate_binary_view, validate_string_view};
 use arrow_schema::{
@@ -36,6 +36,9 @@ use std::fmt::Debug;
 use std::marker::PhantomData;
 use std::ops::{Add, Sub};
 
+// re-export types so that they can be used without importing arrow_buffer explicitly
+pub use arrow_buffer::{IntervalDayTime, IntervalMonthDayNano};
+
 // BooleanType is special: its bit-width is not the size of the primitive type, and its `index`
 // operation assumes bit-packing.
 /// A boolean datatype
@@ -218,84 +221,19 @@ make_type!(
     IntervalYearMonthType,
     i32,
     DataType::Interval(IntervalUnit::YearMonth),
-    "A “calendar” interval stored as the number of whole months."
+    "A 32-bit “calendar” interval type representing the number of whole months."
 );
 make_type!(
     IntervalDayTimeType,
     IntervalDayTime,
     DataType::Interval(IntervalUnit::DayTime),
-    r#"A “calendar” interval type in days and milliseconds.
-
-## Representation
-This type is stored as a single 64 bit integer, interpreted as two i32 fields:
-1. the number of elapsed days
-2. The number of milliseconds (no leap seconds),
-
-```text
- ┌──────────────┬──────────────┐
- │     Days     │ Milliseconds │
- │  (32 bits)   │  (32 bits)   │
- └──────────────┴──────────────┘
- 0              31            63 bit offset
-```
-Please see the [Arrow Spec](https://github.com/apache/arrow/blob/081b4022fe6f659d8765efc82b3f4787c5039e3c/format/Schema.fbs#L406-L408) for more details
-
-## Note on Comparing and Ordering for Calendar Types
-
-Values of `IntervalDayTimeType` are compared using their binary representation,
-which can lead to surprising results. Please see the description of ordering on
-[`IntervalMonthDayNanoType`] for more details
-"#
+    "A “calendar” interval type representing days and milliseconds. See [`IntervalDayTime`] for more details."
 );
 make_type!(
     IntervalMonthDayNanoType,
     IntervalMonthDayNano,
     DataType::Interval(IntervalUnit::MonthDayNano),
-    r#"A “calendar” interval type in months, days, and nanoseconds.
-
-## Representation
-This type is stored as a single 128 bit integer,
-interpreted as three different signed integral fields:
-
-1. The number of months (32 bits)
-2. The number days (32 bits)
-2. The number of nanoseconds (64 bits).
-
-Nanoseconds does not allow for leap seconds.
-Each field is independent (e.g. there is no constraint that the quantity of
-nanoseconds represents less than a day's worth of time).
-
-```text
-┌───────────────┬─────────────┬─────────────────────────────┐
-│     Months    │     Days    │            Nanos            │
-│   (32 bits)   │  (32 bits)  │          (64 bits)          │
-└───────────────┴─────────────┴─────────────────────────────┘
-  0            32             64                           128 bit offset
-```
-Please see the [Arrow Spec](https://github.com/apache/arrow/blob/081b4022fe6f659d8765efc82b3f4787c5039e3c/format/Schema.fbs#L409-L415) for more details
-
-## Note on Comparing and Ordering for Calendar Types
-Values of `IntervalMonthDayNanoType` are compared using their binary representation,
-which can lead to surprising results.
-
-Spans of time measured in calendar units are not fixed in absolute size (e.g.
-number of seconds) which makes defining comparisons and ordering non trivial.
-For example `1 month` is 28 days for February but `1 month` is 31 days
-in December.
-
-This makes the seemingly simple operation of comparing two intervals
-complicated in practice. For example is `1 month` more or less than `30 days`? The
-answer depends on what month you are talking about.
-
-This crate defines comparisons for calendar types using their binary
-representation which is fast and efficient, but leads
-to potentially surprising results.
-
-For example a
-`IntervalMonthDayNano` of `1 month` will compare as **greater** than a
-`IntervalMonthDayNano` of `100 days` because the binary representation of `1 month`
-is larger than the binary representation of 100 days.
-"#
+    r"A “calendar” interval type representing months, days, and nanoseconds. See [`IntervalMonthDayNano`] for more details."
 );
 make_type!(
     DurationSecondType,

arrow-buffer/src/interval.rs

@@ -19,6 +19,52 @@ use crate::arith::derive_arith;
 use std::ops::Neg;
 
 /// Value of an IntervalMonthDayNano array
+///
+///  ## Representation
+///
+/// This type is stored as a single 128 bit integer, interpreted as three
+/// different signed integral fields:
+///
+/// 1. The number of months (32 bits)
+/// 2. The number days (32 bits)
+/// 2. The number of nanoseconds (64 bits).
+///
+/// Nanoseconds does not allow for leap seconds.
+///
+/// Each field is independent (e.g. there is no constraint that the quantity of
+/// nanoseconds represents less than a day's worth of time).
+///
+/// ```text
+/// ┌───────────────┬─────────────┬─────────────────────────────┐
+/// │     Months    │     Days    │            Nanos            │
+/// │   (32 bits)   │  (32 bits)  │          (64 bits)          │
+/// └───────────────┴─────────────┴─────────────────────────────┘
+/// 0            32             64                           128 bit offset
+/// ```
+/// Please see the [Arrow Spec](https://github.com/apache/arrow/blob/081b4022fe6f659d8765efc82b3f4787c5039e3c/format/Schema.fbs#L409-L415) for more details
+///
+///## Note on Comparing and Ordering for Calendar Types
+///
+/// Values of `IntervalMonthDayNano` are compared using their binary
+/// representation, which can lead to surprising results.
+///
+/// Spans of time measured in calendar units are not fixed in absolute size (e.g.
+/// number of seconds) which makes defining comparisons and ordering non trivial.
+/// For example `1 month` is 28 days for February but `1 month` is 31 days
+/// in December.
+///
+/// This makes the seemingly simple operation of comparing two intervals
+/// complicated in practice. For example is `1 month` more or less than `30
+/// days`? The answer depends on what month you are talking about.
+///
+/// This crate defines comparisons for calendar types using their binary
+/// representation which is fast and efficient, but leads
+/// to potentially surprising results.
+///
+/// For example a
+/// `IntervalMonthDayNano` of `1 month` will compare as **greater** than a
+/// `IntervalMonthDayNano` of `100 days` because the binary representation of `1 month`
+/// is larger than the binary representation of 100 days.
 #[derive(Debug, Default, Copy, Clone, Eq, PartialEq, Hash, Ord, PartialOrd)]
 #[repr(C)]
 pub struct IntervalMonthDayNano {
@@ -272,6 +318,30 @@ derive_arith!(
 );
 
 /// Value of an IntervalDayTime array
+///
+/// ## Representation
+///
+/// This type is stored as a single 64 bit integer, interpreted as two i32
+/// fields:
+///
+/// 1. the number of elapsed days
+/// 2. The number of milliseconds (no leap seconds),
+///
+/// ```text
+/// ┌──────────────┬──────────────┐
+/// │     Days     │ Milliseconds │
+/// │  (32 bits)   │  (32 bits)   │
+/// └──────────────┴──────────────┘
+/// 0              31            63 bit offset
+/// ```
+///
+/// Please see the [Arrow Spec](https://github.com/apache/arrow/blob/081b4022fe6f659d8765efc82b3f4787c5039e3c/format/Schema.fbs#L406-L408) for more details
+///
+/// ## Note on Comparing and Ordering for Calendar Types
+///
+/// Values of `IntervalDayTime` are compared using their binary representation,
+/// which can lead to surprising results. Please see the description of ordering on
+/// [`IntervalMonthDayNano`] for more details
 #[derive(Debug, Default, Copy, Clone, Eq, PartialEq, Hash, Ord, PartialOrd)]
 #[repr(C)]
 pub struct IntervalDayTime {