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new b6f87edbba Minor: Improve `Interval` Docs (#7782)
b6f87edbba is described below
commit b6f87edbbaaaedd696b2e448fcd7df7ad3cd2c93
Author: Andrew Lamb <[email protected]>
AuthorDate: Tue Oct 10 06:28:28 2023 -0400
Minor: Improve `Interval` Docs (#7782)
---
.../src/intervals/interval_aritmetic.rs | 37 +++++++++++++++++-----
1 file changed, 29 insertions(+), 8 deletions(-)
diff --git a/datafusion/physical-expr/src/intervals/interval_aritmetic.rs
b/datafusion/physical-expr/src/intervals/interval_aritmetic.rs
index 3ed228517f..210db0ebe6 100644
--- a/datafusion/physical-expr/src/intervals/interval_aritmetic.rs
+++ b/datafusion/physical-expr/src/intervals/interval_aritmetic.rs
@@ -174,10 +174,28 @@ impl Display for IntervalBound {
}
/// This type represents an interval, which is used to calculate reliable
-/// bounds for expressions. Currently, we only support addition and
-/// subtraction, but more capabilities will be added in the future.
-/// Upper/lower bounds having NULL values indicate an unbounded side. For
-/// example; [10, 20], [10, ∞), (-∞, 100] and (-∞, ∞) are all valid intervals.
+/// bounds for expressions:
+///
+/// * An *open* interval does not include the endpoint and is written using a
+/// `(` or `)`.
+///
+/// * A *closed* interval does include the endpoint and is written using `[` or
+/// `]`.
+///
+/// * If the interval's `lower` and/or `upper` bounds are not known, they are
+/// called *unbounded* endpoint and represented using a `NULL` and written
using
+/// `∞`.
+///
+/// # Examples
+///
+/// A `Int64` `Interval` of `[10, 20)` represents the values `10, 11, ... 18,
+/// 19` (includes 10, but does not include 20).
+///
+/// A `Int64` `Interval` of `[10, ∞)` represents a value known to be either
+/// `10` or higher.
+///
+/// An `Interval` of `(-∞, ∞)` represents that the range is entirely unknown.
+///
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct Interval {
pub lower: IntervalBound,
@@ -208,14 +226,17 @@ impl Display for Interval {
impl Interval {
/// Creates a new interval object using the given bounds.
- /// For boolean intervals, having an open false lower bound is equivalent
- /// to having a true closed lower bound. Similarly, open true upper bound
- /// is equivalent to having a false closed upper bound. Also for boolean
+ ///
+ /// # Boolean intervals need special handling
+ ///
+ /// For boolean intervals, having an open false lower bound is equivalent
to
+ /// having a true closed lower bound. Similarly, open true upper bound is
+ /// equivalent to having a false closed upper bound. Also for boolean
/// intervals, having an unbounded left endpoint is equivalent to having a
/// false closed lower bound, while having an unbounded right endpoint is
/// equivalent to having a true closed upper bound. Therefore; input
/// parameters to construct an Interval can have different types, but they
- /// all result in [false, false], [false, true] or [true, true].
+ /// all result in `[false, false]`, `[false, true]` or `[true, true]`.
pub fn new(lower: IntervalBound, upper: IntervalBound) -> Interval {
// Boolean intervals need a special handling.
if let ScalarValue::Boolean(_) = lower.value {
