Implement basic std functions to manipulate arrays

src/std/array.ab

@@ -26,3 +26,30 @@ pub fun includes(array, value) {
     let result = array_first_index(array, value)
     return result >= 0
 }
+
+/// Returns the last element in the array
+pub fun last(array) {
+    return array[len(array) - 1]
+}
+
+/// Removes an element at the index from the array
+pub fun remove_at(ref array: [], index: Num): Null {
+    trust $ unset {nameof array}[{index}] $
+}
+
+/// Removes an element at the index from the array, and returns it
+pub fun extract_at(ref array, index) {
+    let elem = array[index]
+    remove_at(array, index)
+    return elem
+}
+
+/// Removes the last element from the array, and returns it
+pub fun pop(ref array) {
+    return extract_at(array, len(array) - 1)
+}
+
+/// Removes the first element from the array, and returns it
+pub fun shift(ref array) {
+    return extract_at(array, 0)
+}

src/tests/stdlib/array_extract_at.ab

@@ -0,0 +1,12 @@
+import { extract_at, array_first_index } from "std/array"
+
+main {
+    let array = ["Failed", "Extracted", "Failed"]
+
+    if extract_at(array, 1) == "Extracted"
+        and len(array) == 2
+        and array_first_index(array, "Extracted") == -1
+    {
+        echo "Succeeded"
+    }
+}

src/tests/stdlib/array_last.ab

@@ -0,0 +1,6 @@
+import { last } from "std/array"
+
+main {
+        let array = ["Failed", "Not", "Succeeded"]
+        echo last(array)
+}

src/tests/stdlib/array_pop.ab

@@ -0,0 +1,11 @@
+import { pop, array_first_index } from "std/array"
+
+main {
+    let array = ["Failed", "Failed", "Popped"]
+    if pop(array) == "Popped"
+        and len(array) == 2
+        and array_first_index(array, "Popped") == -1
+    {
+        echo "Succeeded"
+    }
+}

src/tests/stdlib/array_remove_at.ab

@@ -0,0 +1,9 @@
+import { remove_at, array_first_index } from "std/array"
+
+main {
+    let array = ["Failed", "Removed", "Failed"]
+    remove_at(array, 1)
+    if len(array) == 2 and array_first_index(array, "Removed") == -1 {
+        echo "Succeeded"
+    }
+}

src/tests/stdlib/array_shift.ab

@@ -0,0 +1,11 @@
+import { shift, array_first_index } from "std/array"
+
+main {
+    let array = ["Shifted", "Failed", "Failed"]
+    if shift(array) == "Shifted"
+        and len(array) == 2
+        and array_first_index(array, "Shifted") == -1
+    {
+        echo "Succeeded"
+    }
+}