Abstract classes and interfaces support?

[CriztianiX]

Trying to make more solid OOP, what do you think about to add abstract classes and interfaces? The checking can be done at compilation time throwing an error maybe.

[pigpigyyy]

It's a good idea. Since interfaces are like some kinds of type info, we might need to implement the static typed system to support these features and get the work done after #15.

[CriztianiX]

Maybe, the #15 is not necessary at all. i think something like PHP/Ruby etc.

Here some examples for interfaces. We need 2 new reserved words. interface and implements

interface Repository
  all: ()
  read: (id)

class UserRepository implements Repository
  all: () =>
  read(id) =>

class BookRepository implements Repository
  all: () =>

In this examples, compilation for BookRepository should be fail due to missing methods

For abstract classes can be something like:

abstract class User
  abstract role: ()

  hello: => ´hello #{@role!}´

class AdminUser extends User
  role: => 'Admin'

class EditorUser extends User

user = User!

• EditorUser should be fail due to missing methods.
• User should be fail. Abstract class cannot be initialized

[gytis-ivaskevicius]

• Typesystem - yes!
• Interfaces/Abstract Classes - I don't think that it is the right way to around it.

Typesystem implementation will end up with some sort of interface or interface-like feature. Abstract Classes - in OOP inheritance it is already strongly discouraged due to lack of flexibility. Not sure why one would encourage it here.

If one were to take a look - Many if not most OOP languages/codebases are adapting ideas/concepts of FP, maybe yuescript should take such ideology as well.

[Sod-Almighty]

Abstract Classes - in OOP inheritance it is already strongly discouraged due to lack of flexibility

Then does Yuescript support mixins? That is, the ability to "include" arbitrary snippets of code into a class?¹

In my opinion, this is a much better solution than traditional OOP. For instance, it avoids the massive clusterfudge of multiple inheritance.

---

¹ Languages that support this include Ruby and Rust.

[pigpigyyy]

Yes, there is a syntax sugar for mixing. You can use it with

class A using B, C

and get

local A -- 1
do -- 1
  local _class_0 -- 1
  local _base_0 = { } -- 1
  local _list_0 = { -- 1
    B, -- 1
    C -- 1
  } -- 1
  for _index_0 = 1, #_list_0 do -- 1
    local _mixin_0 = _list_0[_index_0] -- 1
    for _key_0, _val_0 in pairs(_mixin_0.__base) do -- 1
      if not _key_0:match("^__") then -- 1
        _base_0[_key_0] = _val_0 -- 1
      end -- 1
    end -- 1
  end -- 1
...