Would be nice if there's some method to check if the instance inherits from some class

[wolf81]

A bit like classic, which includes a instance:is(T) method.

The implementation in classic is as follows:

function Object:is(T)
  local mt = getmetatable(self)
  while mt do
    if mt == T then
      return true
    end
    mt = getmetatable(mt)
  end
  return false
end

It's probably possible to do the same here (will check soon and make PR if possible).

Source: https://github.com/rxi/classic/blob/master/classic.lua

[vrld]

This won't work as in classic, because hump does not really do inheritance. Instead, class:include(other) copies entries from other. So class:is(other) would have to check the meta table and if it does not match it would have to check whether all entries of other are also in class and (have the same type). I imagine this can be quite expensive.

I am also not a fan of such a method, because it encourages bad code:tm:. In most cases you should rely on polymorphism instead. If you really, really need to, you can use duck typing instead. Though really, one should try to use composition over inheritance.

Feel free to convince me otherwise.

[wolf81]

@vrld Sorry for late response and thanks for your answer. Your answer makes sense.

With regards to hump.class, I decided to use a different approach now, a little bit based on ECS. I have an entity and at can include various components which will be added to an array inside the class. This way, I can check types of components in a clean way (using getmetatable check).