feat: add insertion sort

Added a complete insertion sort implementation including description.
Made left arrow swap again because it makes more sense with insertion
sort. Also included a nice quality-of-life feature where the game
remembers the last played level and automatically highlights it for the
next game.

Author: danielzting

levels/bubble_sort.gd

@@ -7,6 +7,7 @@ each pair of elements, swapping them if they are out of order. When it
 has gone through the entire array without swapping a single pair, it has
 finished. Though simple to understand, bubble sort is hopelessly
 inefficient on all but the smallest of arrays."""
+var index = 0
 var swapped = false
 
 func _init(array).(array):

levels/comparison_sort.gd

@@ -7,7 +7,6 @@ signal mistake
 const ACTIONS = ["swap", "no_swap"]
 
 var array: ArrayModel
-var index = 0
 var timer = Timer.new()
 var active = true
 

levels/insertion_sort.gd

@@ -0,0 +1,38 @@
+extends ComparisonSort
+class_name InsertionSort
+
+const TITLE = "INSERTION SORT"
+const ABOUT = """Insertion sort goes through the array and inserts each
+element into its correct position. It is most similar to how most people
+would sort a deck of cards. It is also slow on large arrays but it is
+one of the faster quadratic algorithms. It is often used to sort smaller
+subarrays in hybrid sorting algorithms."""
+var end = 1
+var index = end
+
+func _init(array).(array):
+    pass
+
+func check(action):
+    if array.get(index - 1) > array.get(index):
+        return action == "swap"
+    else:
+        return action == "no_swap"
+
+func next():
+    if array.get(index - 1) > array.get(index):
+        array.swap(index - 1, index)
+        index -= 1
+        if index == 0:
+            _grow()
+    else:
+        _grow()
+
+func _grow():
+    end += 1
+    if end == array.size:
+        emit_signal("done")
+    index = end
+
+func emphasized(i):
+    return i == index or i == index - 1

project.godot

@@ -33,13 +33,19 @@ _global_script_classes=[ {
 "class": "ComparisonSort",
 "language": "GDScript",
 "path": "res://levels/comparison_sort.gd"
+}, {
+"base": "ComparisonSort",
+"class": "InsertionSort",
+"language": "GDScript",
+"path": "res://levels/insertion_sort.gd"
 } ]
 _global_script_class_icons={
 "ArrayModel": "",
 "ArrayView": "",
 "BogoSort": "",
 "BubbleSort": "",
-"ComparisonSort": ""
+"ComparisonSort": "",
+"InsertionSort": ""
 }
 
 [application]
@@ -106,12 +112,12 @@ ui_down={
 }
 swap={
 "deadzone": 0.5,
-"events": [ Object(InputEventKey,"resource_local_to_scene":false,"resource_name":"","device":0,"alt":false,"shift":false,"control":false,"meta":false,"command":false,"pressed":false,"scancode":16777233,"unicode":0,"echo":false,"script":null)
+"events": [ Object(InputEventKey,"resource_local_to_scene":false,"resource_name":"","device":0,"alt":false,"shift":false,"control":false,"meta":false,"command":false,"pressed":false,"scancode":16777231,"unicode":0,"echo":false,"script":null)
  ]
 }
 no_swap={
 "deadzone": 0.5,
-"events": [ Object(InputEventKey,"resource_local_to_scene":false,"resource_name":"","device":0,"alt":false,"shift":false,"control":false,"meta":false,"command":false,"pressed":false,"scancode":16777231,"unicode":0,"echo":false,"script":null)
+"events": [ Object(InputEventKey,"resource_local_to_scene":false,"resource_name":"","device":0,"alt":false,"shift":false,"control":false,"meta":false,"command":false,"pressed":false,"scancode":16777233,"unicode":0,"echo":false,"script":null)
  ]
 }
 

scenes/levels.tscn

@@ -85,8 +85,8 @@ size_flags_horizontal = 3
 size_flags_vertical = 3
 text = "INSTRUCTIONS
 
-LEFT ARROW: CONTINUE
-RIGHT ARROW: SWAP"
+LEFT ARROW: SWAP
+RIGHT ARROW: CONTINUE"
 autowrap = true
 
 [node name="Timer" type="Timer" parent="."]

scripts/end.gd

@@ -5,4 +5,5 @@ func _ready():
     $Button.grab_focus()
 
 func _on_Button_pressed():
-    scene.change_scene("res://scenes/levels.tscn")
+    scene.change_scene("res://scenes/levels.tscn",
+        {"level": scene.get_param("level")})

scripts/levels.gd

@@ -2,6 +2,7 @@ extends HBoxContainer
 
 var levels = [
     BubbleSort,
+    InsertionSort,
 ]
 var level: ComparisonSort
 
@@ -14,8 +15,10 @@ func _ready():
         button.connect("focus_entered", self, "_on_Button_focus_changed")
         button.connect("pressed", self, "_on_Button_pressed", [level.TITLE])
         $LevelsBorder/Levels.add_child(button)
-    # Automatically focus on first button
-    $LevelsBorder/Levels.get_child(0).grab_focus()
+        if scene.get_param("level") == level:
+            button.grab_focus()
+    if scene.get_param("level") == null:
+        $LevelsBorder/Levels.get_child(0).grab_focus()
 
 func _on_Button_focus_changed():
     level = get_level(get_focus_owner().text).new(ArrayModel.new(10))

scripts/play.gd

@@ -22,4 +22,5 @@ func get_score():
     return stepify((OS.get_ticks_msec() - start_time) / 1000.0, 0.001)
 
 func _on_Level_done():
-    scene.change_scene("res://scenes/end.tscn", {"score": get_score()})
+    scene.change_scene("res://scenes/end.tscn",
+        {"level": scene.get_param("level"), "score": get_score()})