Generics in class inheritance

[jkopano]

Hello, i would like to ask for help

lets say i have class like this one:

---@class entity.class<T>
---@field signals table
---@field emit fun(self: self, s: `T`, ...)
---@field register fun(self: self, s: `T`, f: fun(...))
local Entity = class("entity")

function Entity:emit(event, ...)
  if self.signals == nil then return end

  self.signals:emit(event, ...)
end

function Entity:register(event, f)
  if self.signals == nil then return end

  self.signals:register(event, f)
end

return Entity

now for i have class that inherits from entity.class like this one:

---@alias signals.player
---|"update"
---|"before_draw"
---|"draw"
---|"after_draw"
---|"destroy"
---|"take_damage"
---|"dead"
---|"attack"
---|"running"
---|"move"
---|"idle"
---|"heal"
---|"after_attack"
---|"after_dead"
---|"after_running"
---|"look"

---@class player.class: entity.class<signals.player>

So yeah, the code i provided is not working.

Is there a way for this to work?

[jkopano]

Of course apart from not doing the inheritance and just documenting the emit and register functions for every subclass

[CppCXY]

luals donot support generic class, I suggest you try emmylua_ls

[tomlau10]

I found a way to make it work for entity.class<signals.player>

---@class entity.class<T>: {
--- emit: fun(self, event: T, ...),
--- register: fun(self, event: T, f: fun(...)),
---}
---@field signals table

---@alias signals.player
---|"update"
---|"before_draw"
---|"draw"
---|"after_draw"
---|"destroy"
---|"take_damage"
---|"dead"
---|"attack"
---|"running"
---|"move"
---|"idle"
---|"heal"
---|"after_attack"
---|"after_dead"
---|"after_running"
---|"look"

---@type entity.class<signals.player>
local e
e:emit() --< completion works here

• but it doesn't work if it is inherited by another class 😕

---@class player.class: entity.class<signals.player>
local Player

Player:emit() --< but not working here, shows: Undefined field `emit`.

---

updated: I found a hack ?!

Alright I think I found a hack 😂

• define player.class using alias + union type instead of inheritance

-- entity definition same as above ...

---@diagnostic disable-next-line: duplicate-doc-alias
---@alias player.class player.class|entity.class<signals.player>

---@class player.class
local Player

Player:emit() --< now the completion works !!