feat(std/array): Add array_filled (#783)

* feat(std): array_filled

* Remove test for array_filled

* Add default value to `array_filled`

* Change description of `array_filled`

* Change comments to triple slash

* Apply suggestions from code review

Change type tests for stronger assertion.

Co-authored-by: Paweł Karaś <pkaras.it@gmail.com>

---------

Co-authored-by: Paweł Karaś <pkaras.it@gmail.com>

Author: UrbanCoffee

src/std/array.ab

@@ -86,3 +86,15 @@ pub fun array_shift(ref array) {
     array = array[1..length]
     return element
 }
+
+/// Returns an array of length `size` with each element set to `value`; if `size`
+/// is less than zero or not of type `Int`, an empty array is returned 
+pub fun array_filled(size, value = 0) {
+    let array = [value]
+    array = array[0..0]
+    if not (size is Int):
+        return array 
+    for _ in 0..(size >= 0 then size else 0):
+        array += [value]
+    return array
+}

src/tests/stdlib/array_filled_same_values.ab

@@ -0,0 +1,18 @@
+import { array_filled } from "std/array"
+
+// Output
+// [0 0 0]
+// [0 0 0]
+// [.5 .5 .5]
+// [a a a]
+// [0 0 0]
+// [  ]
+
+main {
+    echo "[{array_filled(3)}]"
+    echo "[{array_filled(3, 0)}]"
+    echo "[{array_filled(3, .5)}]"
+    echo "[{array_filled(3, "a")}]"
+    echo "[{array_filled(3, false)}]"
+    echo "[{array_filled(3, null)}]"
+}

src/tests/stdlib/array_filled_size.ab

@@ -0,0 +1,19 @@
+import { array_filled } from "std/array"
+
+// Output
+// Array length for size=-1: 0
+// Array length for size=0: 0
+// Array length for size=1: 1 
+// Array length for size=2: 2 
+// Array length for size=3: 3
+
+fun test_size(size: Int): Null {
+    let array = array_filled(size, 0)
+    echo "Array length for size={size}: {len(array)}"
+}
+
+main {
+    for i in -1..=3 {
+        test_size(i)
+    }
+}

src/tests/stdlib/array_filled_type_bool.ab

@@ -0,0 +1,9 @@
+import { array_filled } from "std/array"
+
+main {
+    let array = array_filled(0, true)
+    if array == [Bool]:
+        echo "Succeeded"
+    else:
+        echo "Failed"
+}

src/tests/stdlib/array_filled_type_int.ab

@@ -0,0 +1,9 @@
+import { array_filled } from "std/array"
+
+main {
+    let array = array_filled(0, 1)
+    if array == [Int]:
+        echo "Succeeded"
+    else:
+        echo "Failed"
+}

src/tests/stdlib/array_filled_type_null.ab

@@ -0,0 +1,9 @@
+import { array_filled } from "std/array"
+
+main {
+    let array = array_filled(0, null)
+    if array == [Null]:
+        echo "Succeeded"
+    else:
+        echo "Failed"
+}

src/tests/stdlib/array_filled_type_num.ab

@@ -0,0 +1,9 @@
+import { array_filled } from "std/array"
+
+main {
+    let array = array_filled(0, 1.0)
+    if array == [Num]:
+        echo "Succeeded"
+    else:
+        echo "Failed"
+}

src/tests/stdlib/array_filled_type_text.ab

@@ -0,0 +1,9 @@
+import { array_filled } from "std/array"
+
+main {
+    let array = array_filled(0, "")
+    if array == [Text]:
+        echo "Succeeded"
+    else:
+        echo "Failed"
+}