feat(#31): add plus operations for AnyInt

changelog.md

@@ -22,16 +22,33 @@ All notable changes to this project will be documented in this file.
 
 ### Added
 
-Introduce a new `NotEmptyCollection` hierarchy representing collections that
-contain at least one element (issue
-[#14](https://github.com/kotools/types/issues/14)).
+- Introduce a new `NotEmptyCollection` hierarchy representing collections that
+  contain at least one element (issue
+  [#14](https://github.com/kotools/types/issues/14)).
 
 ```kotlin
 interface NotEmptyCollection<out E>
 class NotEmptyList<out E> : NotEmptyCollection<E>
 class NotEmptySet<out E> : NotEmptyCollection<E>
 ```
 
+- Binary operations (`plus`) for the `AnyInt` hierarchy (issue
+  [#31](https://github.com/kotools/types/issues/31)).
+
+```kotlin
+val x: AnyInt = NonZeroInt.random()
+val y: AnyInt = PositiveInt.random()
+var result: Int
+// before
+result = 1 + x.toInt()
+result = x.toInt() + 1
+result = x.toInt() + y.toInt()
+// after
+result = 1 + x
+result = x + 1
+result = x + y
+```
+
 ### Changed
 
 - Support for

src/commonMain/kotlin/kotools/types/number/AnyInt.kt

@@ -23,6 +23,18 @@ public sealed interface AnyInt {
     override fun toString(): String
 }
 
+/** Adds the [other] integer to this one. */
+@SinceKotoolsTypes("4.1")
+public operator fun Int.plus(other: AnyInt): Int = this + other.toInt()
+
+/** Adds the [other] integer to this one. */
+@SinceKotoolsTypes("4.1")
+public operator fun AnyInt.plus(other: Int): Int = toInt() + other
+
+/** Adds the [other] integer to this one. */
+@SinceKotoolsTypes("4.1")
+public operator fun AnyInt.plus(other: AnyInt): Int = toInt() + other
+
 internal sealed interface AnyIntSerializer<I : AnyInt> : KSerializer<I> {
     val serialName: Result<NotBlankString>
 

src/commonTest/kotlin/kotools/types/number/AnyIntTest.kt

@@ -9,6 +9,32 @@ import kotools.types.shouldEqual
 import kotlin.random.Random
 import kotlin.test.Test
 
+class AnyIntTest {
+    @Test
+    fun int_plus_should_pass() {
+        val x: Int = Random.nextInt()
+        val y: AnyInt = NonZeroInt.random()
+        val result: Int = x + y
+        result shouldEqual x + y.toInt()
+    }
+
+    @Test
+    fun plus_should_pass_with_an_Int() {
+        val x: AnyInt = PositiveInt.random()
+        val y: Int = Random.nextInt()
+        val result: Int = x + y
+        result shouldEqual x.toInt() + y
+    }
+
+    @Test
+    fun plus_should_pass_with_an_AnyInt() {
+        val x: AnyInt = PositiveInt.random()
+        val y: AnyInt = NegativeInt.random()
+        val result: Int = x + y
+        result shouldEqual x.toInt() + y.toInt()
+    }
+}
+
 class AnyIntSerializerTest {
     private val serializer: KSerializer<AnyInt> = AnyIntSerializerImplementation