Implement Median for slice types with macro

[rustaceanrob]

Attempting to remove the repeated logic here, but also trying to avoid the trait hell that is required for implementing Median in a generic way. I extracted the logic into a macro which is reusable for any type of interest to implement Median

cc @nyonson

[nyonson]

Dang is there really no good trait combo to describe "numbers"? I am a macro noob so I am gonna just play around with this one to learn it.

[rustaceanrob]

I would say a number is described by the following T: Copy + PartialOrd + Default + std::ops::Add<Output = T> + std::ops::Div<Output = T> + From<u8>, which is horrible. I prefer the macro because the arithmetic is clear and there are no weird From::(2) type shit going on

ref: https://internals.rust-lang.org/t/please-can-we-add-a-basic-num-trait/16449

[nyonson]

I would say a number is described by the following T: Copy + PartialOrd + Default + std::ops::Add<Output = T> + std::ops::Div<Output = T> + From<u8>, which is horrible. I prefer the macro because the arithmetic is clear and there are no weird From::(2) type shit going on

ref: https://internals.rust-lang.org/t/please-can-we-add-a-basic-num-trait/16449

Wow yea. I guess we could shove that in an alias and boil it down to just the bare minimum requirement for the function (which could be what you have already), but we till wouldn't get away from the weird From::(2) stuff.

[rustaceanrob]

Either From::(2) or 2.into(), which I find equally strange. With the macro all of the abstraction is in defining the trait and the actual implementation is more legible imo.

[nyonson]

Yea, I still find the macro syntax wierd, but that is me just not knowing. I think the macro is essentially doing what the compiler would too for the trait bound?

[nyonson]

Concept ACK 73beeaa

I am gonna take some time to finally learn macros

[rustaceanrob]

think the macro is essentially doing what the compiler would too for the trait bound?

Yeah, the compiler will re-implement the trait for each type that ends up using it