Add tutorial for Conditions (#206)

docs/README.md

@@ -14,6 +14,7 @@
     -   [Variable Instancer](./tutorials/variable-instancer.md)
     -   [Event Instancer](./tutorials/event-instancer.md)
     -   [Generator](./tutorials/generator.md)
+    -   [Conditions](./tutorials/conditions.md)    
     -   [Advanced example](./tutorials/advanced-example.md)
     -   [Usage with UniRX](./tutorials/unirx.md)
 -   API

docs/tutorials/conditions.md

@@ -0,0 +1,85 @@
+---
+id: conditions
+title: Conditions
+hide_title: true
+sidebar_label: Conditions
+---
+
+# Conditions
+
+`Conditions` control whether a listener responds to an event or not. `Conditions` are specialized `Functions`.
+
+The following script will add a condition for the type `int` to the Atom creation menu:
+
+```cs
+using UnityEngine;
+using UnityAtoms;
+using UnityAtoms.BaseAtoms;
+
+// Set the icon you will see in the editor
+[EditorIcon("atom-icon-sand")]
+
+// Set the path in the asset creation menu
+[CreateAssetMenu(menuName = "Unity Atoms/Conditions/Int/MultipleOf", fileName = "MultipleOf")]
+
+public class MultipleOf : IntCondition
+{
+    // Can be set via the Inspector
+    public int multiple;
+
+    public override bool Call(int value)
+    {
+        // The condition implementation must return a boolean value
+
+        return value % multiple == 0;
+    }
+}
+```
+
+> **Note:** Use the generator to generate the corresponding `Condition` base class for any type you might need in your project.
+
+Notice how the script extends the `IntCondition` class and the usual `Call` method of a `Function` returns a `bool`.
+
+It is now possible to create new conditions for the type `int` under the path described in the script:
+
+![create-condition](../assets/conditions/create-condition.png)
+
+Create two conditions and assign a different parameter for each:
+
+![multiple-of-three](../assets/conditions/multiple-of-three.png)
+
+![multiple-of-five](../assets/conditions/multiple-of-five.png)
+
+Now these assets can be used in any `IntListener`. Create a simple logging script to test it out:
+
+```cs
+using UnityEngine;
+
+public class LogSomething : MonoBehaviour
+{
+    public void Report(int value)
+    {
+        Debug.Log(gameObject.name + " reports: " + value);
+    }
+}
+```
+
+To test this, create an `IntEvent` called `SomeIntChanged`. This will be used to raise it from the `Inspector` during testing:
+
+![test-int-event](../assets/conditions/test-int-event.png)
+
+Create a new `GameObject` and rename it to `Unfiltered` for testing purposes. Add an `IntEventReferenceListener` and `LogSomething` components to the `GameObject` and wire the listener to listen for `SomeIntChanged` event. Add a dynamic Unity Event response (the `Report` method of the `LogSomething` component of the same `GameObject`). The end result should look like this:
+
+![unfiltered-gameobject](../assets/conditions/unfiltered-gameobject.png)
+
+Now `Unfiltered` will simply respond to any value passed when `SomeIntChanged` is raised. Enter play mode and test it by clicking on "Raise" from the `Inspector`. The console should log the value in the "Inspector Raise Value" field.
+
+Duplicate `Unfiltered` and rename the duplicate to `Filtered`. Add the previously created condition assets to the `Conditions` array and choose a logical operator to test. `Filtered` now looks like this:
+
+![filtered-gameobject](../assets/conditions/filtered-gameobject.png)
+
+Now enter play mode again and see that the conditions apply. The `Filtered` one only responds when the value fulfills either of the conditions, since the logical operator is `And`:
+
+![conditions-in-use](../assets/conditions/conditions-in-use.png)
+
+That's it! The conditions are taking effect and can be swapped in or out in the `Inspector` without coding.

website/i18n/en.json

@@ -128,6 +128,10 @@
         "title": "Advanced example",
         "sidebar_label": "Advanced example"
       },
+      "tutorials/conditions": {
+        "title": "Conditions",
+        "sidebar_label": "Conditions"
+      },
       "tutorials/event-instancer": {
         "title": "Event Instancer",
         "sidebar_label": "Event Instancer"

website/sidebars.json

@@ -24,7 +24,8 @@
         "ids": [
           "tutorials/variable-instancer",
           "tutorials/event-instancer",
-          "tutorials/generator"
+          "tutorials/generator",
+          "tutorials/conditions"
         ]
       },
       {