Introducing default trait methods

[Champii]

No description provided.

[Champii]

This PR introduces default methods for traits:

trait Foo a
  @default_method: -> @

impl Foo Int64

main: -> (2).default_method!

[Champii]

We need a mecanism to allow impl to override a default method.

[Champii]

Should add relevant issues from comments

[Champii]

Need tests

[Champii]

Need doc

[oraqlle]

What do you need me to review. The code or the idea. Also, what does a default method mean. As in that in the trait definition, we can declare a default implementation of a trait method that might be overridden?

[Champii]

What do you need me to review. The code or the idea.

Principally the idea, but I would not refuse you picking a quick glance at the code, you might have some useful insights I'm missing

Also, what does a default method mean. As in that in the trait definition, we can declare a default implementation of a trait method that might be overridden?

Yes, that's it. That way you can offer some basic logic that you can plug effortless into any type.
That, in coordination with a future "trait dependency" (like a trait bound in Rust), we could have a powerful abstract system.

[Champii]

I think we are all good for this one, waiting for your review before merging :)

[oraqlle]

What is another POD type in Rock besides Int64?

[oraqlle]

Looks Good!

Tested the old README.md stuff, had to get some of the updated versions such as the new impl but other than that it works.

Utilising the default methods is super clean and efficient. One thing I will point out for a future update is that when using the @ self symbol, the trait default trait declaration allows for a dot to preceed the method name as well as not allowing for it. ie. It doesn't enforce a dot or not a dot.
eg.

trait Foo a
    @de: -> @print!

This is the same as

trait Foo a
    @de: -> @.print!

We might want to enforce a particular syntax for consistency. Personally, I like the no-dot as it implies a sort-of auto dot.

[Champii]

What is another POD type in Rock besides Int64?

You can find all the currently implemented primitive types of Rock at https://github.com/Champii/Rock/blob/master/src/lib/ty/primitive_type.rs#L4
Note that struct is part of the greater Type but is still implemented as C struct type by LLVM

Tested the old README.md stuff, had to get some of the updated versions such as the new impl but other than that it works.

Is there some stuff I forgot to update in the readme ?
Also, so that you know, most of the readme stuff is replicated in the unit tests, that are run at each commit. There is still the matter of a mistake, so maybe we could have a system to use the actual code of the working tests to populate the readme. That way we are sure everything works by default, and you won't have to manually try each snippet yourself :)

One thing I will point out for a future update is that when using the @ self symbol, the trait default trait declaration allows for a dot to preceed the method name as well as not allowing for it. ie. It doesn't enforce a dot or not a dot.

This stuff is actually intended, and it will be difficult to enforce it. The primary concern is about the future macro system, that will have to make generic syntactic constructs that work for every identifier type. As we could write stuff like

macro my_macro
  $my_ident:ident =>
    $my_ident.print!

When applied to @, it expands to @.print! and this should still be valid. I'm also a partisan of the point-free notation for @, but I guess it will be easier to enforce it as a convention or best-practice.