Allow explicitly defining interfaces in GDScript

### Describe the project you are working on I'm working on a game where different entities can share similar behaviors, but this proposal is specific to GDScript, so it can apply to a wide range of projects. ### Describe the problem or limitation you are having in your project Let's say we're making a simple shooter game. The player can shoot a `Bullet`. Bullets can hit a `Ship` and `Building`. There are also `Tree` entities that cannot be hit by bullets. Here's some simple code (unrelated code omitted for simplicity). **Ship.gd** ```gdscript extends Node2D class_name Ship func die() -> void: print("Died") ``` **Building.gd** ```gdscript extends Node2D class_name Building func die() -> void: print("Died") ``` **Tree.gd** ```gdscript extends Node2D class_name Tree func die() -> void: print("Died") ``` **Bullet.gd** ```gdscript extends Node2D class_name Bullet func on_body_entered(body: Node2D) -> void: if body.has_method("die"): body.die() ``` There are a few problems with this duck-typing approach: 1. The function "die" is referenced as a string which is error-prone 2. In `Bullet.gd` there is no code auto-completion or checking when calling `body.die()` so you need to implicitly know that that function exists. 3. The mere presence of a function named `die` is not enough to determine what kind of object you're dealing with. In this example, we don't want bullets to hit `Tree`, even though a tree might happen to have a function named `die` (the tree c

Posted by nebs on Jul 14, 2022, 1:44 PM

Tags

• github (Other)

Related issues

• struct's lifetime requirements can be bypassed via covariant field assignment
• Proposal to Reorganize the Moderation Team and Review Moderation Policies
• Progressive FPS degradation appears to be related to dota2.com — blocking the domain prevents the performance loss
• proposal: container/...: generic collection types
• Better Custom Endpoint BYOK
• A concrete policy for backward compatibility until Godot 5.0