Add shift infex operators

Closes #66

Author: Whathecode

README.md

@@ -14,6 +14,7 @@ val interval: IntInterval = interval( 0, 10, isEndIncluded = false )
 val areIncluded = 0 in interval && 5 in interval // true
 val areExcluded = 10 !in interval && 15 !in interval // true
 val size: UInt = interval.size // 10
+val shifted = interval shr 10u // Shifted right by 10: [10, 20)
 ```
 
 This protects against overflows (e.g. if `size > Int.MAX_VALUE`) but also offers better semantics.
@@ -24,6 +25,7 @@ val now = Clock.System.now()
 val interval: InstantInterval = interval( now, now + 100.seconds )
 val areIncluded = now + 50.seconds in interval // true
 val size: Duration = interval.size // 100 seconds
+val shifted = interval shr 24.hours // 100 seconds 24 hours from now
 ```
 
 ## Interval Unions
@@ -36,6 +38,7 @@ Since operations are generally defined on the base interface, you can easily cha
 val start = interval( 0, 100 ) // Interval: [0, 100]
 val areIncluded = 50 in start && 100 in start // true
 val splitInTwo = start - interval( 25, 85 ) // Union: [[0, 25), (85, 100]]
+val shiftBackAndForth = splitInTwo shr 100u shl 100u // == splitInTwo
 val areExcluded = 50 !in splitInTwo && 85 !in splitInTwo // true
 val unite = splitInTwo + interval( 10, 90 ) // Interval: [0, 100]
 val backToStart = start == unite // true
@@ -63,18 +66,18 @@ Instead, new instances are returned if the operation results in a different set
 
 The following operations are available for any `IntervalUnion<T, TSize>`:
 
-|      Operation      |                                         Description                                          | 
-|:-------------------:|:--------------------------------------------------------------------------------------------:|
-|     `isEmpty()`     |                           Determines whether this is an empty set.                           |
-|    `getBounds()`    |                          Gets the upper and lower bound of the set.                          |
-| `contains()` (`in`) |                         Determines whether a value lies in the set.                          |
-|   `minus()` (`-`)   |                              Subtract an interval from the set.                              |
-|   `plus()` (`+`)    |                                 Add an interval to the set.                                  |
-|      `shift()`      |                           Move the interval by a specified offset.                           |
-|   `intersects()`    |                Determines whether another interval intersects with this set.                 |
-|    `setEquals()`    |                     Determines whether a set represents the same values.                     |
-|    `iterator()`     |                      Iterate over all intervals in the union, in order.                      |
-|    `toString()`     | Output as a string using common interval notation, e.g., `[0, 10]` or `[[0, 10), (10, 20]]`. |
+|        Operation        |                                         Description                                          | 
+|:-----------------------:|:--------------------------------------------------------------------------------------------:|
+|       `isEmpty()`       |                           Determines whether this is an empty set.                           |
+|      `getBounds()`      |                          Gets the upper and lower bound of the set.                          |
+|   `contains()` (`in`)   |                         Determines whether a value lies in the set.                          |
+|     `minus()` (`-`)     |                              Subtract an interval from the set.                              |
+|     `plus()` (`+`)      |                                 Add an interval to the set.                                  |
+| `shift()` (`shl`/`shr`) |                           Move the interval by a specified offset.                           |
+|     `intersects()`      |                Determines whether another interval intersects with this set.                 |
+|      `setEquals()`      |                     Determines whether a set represents the same values.                     |
+|      `iterator()`       |                      Iterate over all intervals in the union, in order.                      |
+|      `toString()`       | Output as a string using common interval notation, e.g., `[0, 10]` or `[[0, 10), (10, 20]]`. |
 
 The following operations are specific to `Interval<T, TSize>`:
 

kotlinx.interval.datetime/src/commonTest/kotlin/Readme.kt

@@ -5,6 +5,7 @@ package io.github.whathecode.kotlinx.interval.datetime
 import kotlinx.datetime.Clock
 import kotlin.test.*
 import kotlin.time.Duration
+import kotlin.time.Duration.Companion.hours
 import kotlin.time.Duration.Companion.seconds
 
 
@@ -17,5 +18,6 @@ class Readme
         val interval: InstantInterval = interval( now, now + 100.seconds )
         val areIncluded = now + 50.seconds in interval // true
         val size: Duration = interval.size // 100 seconds
+        val shifted = interval shr 24.hours // 100 seconds 24 hours from now
     }
 }

kotlinx.interval/src/commonMain/kotlin/IntervalUnion.kt

@@ -49,6 +49,20 @@ sealed interface IntervalUnion<T : Comparable<T>, TSize : Comparable<TSize>> : I
      */
     fun shift( amount: TSize, invertDirection: Boolean = false ): ShiftResult<IntervalUnion<T, TSize>, TSize>
 
+    /**
+     * Returns an [IntervalUnion] offset to the right from this interval union by the specified [amount],
+     * or as much as possible before the minimum or maximum value that can be represented by [T] is reached.
+     * Use [shift] in case you want to verify whether the interval could be offset the full [amount].
+     */
+    infix fun shr( amount: TSize ): IntervalUnion<T, TSize> = shift( amount ).shiftedInterval
+
+    /**
+     * Returns an [IntervalUnion] offset to the left from this interval union by the specified [amount],
+     * or as much as possible before the minimum or maximum value that can be represented by [T] is reached.
+     * Use [shift] in case you want to verify whether the interval could be offset the full [amount].
+     */
+    infix fun shl( amount: TSize ): IntervalUnion<T, TSize> = shift( amount, invertDirection = true ).shiftedInterval
+
     /**
      * Determines whether [interval] has at least one value in common with this set.
      */

kotlinx.interval/src/commonTest/kotlin/Readme.kt

@@ -14,6 +14,7 @@ class Readme
         val areIncluded = 0 in interval && 5 in interval // true
         val areExcluded = 10 !in interval && 15 !in interval // true
         val size: UInt = interval.size // 10
+        val shifted = interval shr 10u // Shifted right by 10: [10, 20)
     }
 
     @Test
@@ -22,6 +23,7 @@ class Readme
         val start = interval( 0, 100 ) // Interval: [0, 100]
         val areIncluded = 50 in start && 100 in start // true
         val splitInTwo = start - interval( 25, 85 ) // Union: [[0, 25), (85, 100]]
+        val shiftBackAndForth = splitInTwo shr 100u shl 100u // == splitInTwo
         val areExcluded = 50 !in splitInTwo && 85 !in splitInTwo // true
         val unite = splitInTwo + interval( 10, 90 ) // Interval: [0, 100]
         val backToStart = start == unite // true