Reduce boilerplates and improve ergonomics

[Multirious]

Currently the core APIs is designed around ECS so we can't do anything about it. Using commands.spawn() purely would be an ergonomics hell for complex animations. We can mitigate this by using builders, shortcuts, and helpers which is implemented in the crate. I'd like to discuss further and gather up ideas to improve this through this discussion, join in if you have any ideas or extra information!

[Multirious]

That's completely fine. All these combinators does is just playing around with the offset inside TweensBuilder. If the type matched, it will work. I've been making sure that these combinators will work intuitively.

In actual code,

• sequence does nothing special because it expects all combinators to shift the offset by their own already. So sequence just call all combinators in the tuple in order to emulate sequence.
• parallel
  1. saves the current offset
  2. for every combinators inside the tuple elements, use the same saved offset.
  3. The post-parallel offset will be the longest offset it has recorded from all combinators in parallel.
  4. emulated parallel that also works inside sequence!

I might change how they works after this comment but that's how it is for now.

[musjj]

Very neat, seems solid to me! Another thought: are tuples the right choice? I'm not sure how it's implemented, but I'm guessing it's done like in bevy (e.g. impl T for (U, U, U)) due to the lack of variadics. If so, aren't iterators/lists a better choice so that there's no upper limit?

[Multirious]

They're tuples and implemented like Bevy, yep. Iterators will work but they're limited to only 1 type while tuples allows for mix and match any combinators of any types. It's possible to use macro that will allows for infinite elements but rust-analyzer and cargo-fmt is barely working inside them so tuples are the best choice for ergonomics right now. Tuples is implemented upward of 16 elements but it can be nested so you don't have to worry about elements limit.

[musjj]

Ok, that makes sense 👍

[Multirious]

Completed by v0.5.0

[Multirious]

Update: Now implemented by 606c3d2

[Multirious]

Completed by v0.5.0