feat(#12): overload element's insertion in NotEmptyMutableCollection

src/main/kotlin/kotools/types/collections/NotEmptyMutableCollection.kt

@@ -1,6 +1,8 @@
 package kotools.types.collections
 
 import kotools.types.annotations.SinceKotoolsTypes
+import kotools.types.number.PositiveInt
+import kotools.types.number.StrictlyPositiveInt
 
 /**
  * Represents mutable collections containing at least one element.
@@ -10,13 +12,55 @@ import kotools.types.annotations.SinceKotoolsTypes
 @SinceKotoolsTypes("1.3")
 public sealed interface NotEmptyMutableCollection<E> : MutableCollection<E>,
     NotEmptyCollection<E> {
+    // ---------- Positional Access Operations ----------
+
     /**
      * Inserts the [element] into this list at the specified [index], or throws
      * an [IndexOutOfBoundsException] if the [index] is out of bounds.
      */
     @Throws(IndexOutOfBoundsException::class)
     public fun add(index: Int, element: E)
 
+    /**
+     * Inserts the [element] into this list at the specified [index], or throws
+     * an [IndexOutOfBoundsException] if the [index] is out of bounds.
+     */
+    @Throws(IndexOutOfBoundsException::class)
+    public fun add(index: PositiveInt, element: E): Unit =
+        add(index.value, element)
+
+    /**
+     * Inserts the [element] into this list at the specified [index], or throws
+     * an [IndexOutOfBoundsException] if the [index] is out of bounds.
+     */
+    @Throws(IndexOutOfBoundsException::class)
+    public fun add(index: StrictlyPositiveInt, element: E): Unit =
+        add(index.value, element)
+
+    /**
+     * Inserts the [element] into this list at the specified [index], or returns
+     * `null` if the [index] is out of bounds.
+     */
+    public fun addOrNull(index: Int, element: E): Unit? = try {
+        add(index, element)
+    } catch (_: IndexOutOfBoundsException) {
+        null
+    }
+
+    /**
+     * Inserts the [element] into this list at the specified [index], or returns
+     * `null` if the [index] is out of bounds.
+     */
+    public fun addOrNull(index: PositiveInt, element: E): Unit? =
+        addOrNull(index.value, element)
+
+    /**
+     * Inserts the [element] into this list at the specified [index], or returns
+     * `null` if the [index] is out of bounds.
+     */
+    public fun addOrNull(index: StrictlyPositiveInt, element: E): Unit? =
+        addOrNull(index.value, element)
+
     /**
      * Removes an element at the specified [index] from the list, or throws an
      * [IndexOutOfBoundsException] if the index is out of bounds.