Const generics

[kpp]

Const generics are getting more popular. I can try to implement heapless using const generics and push it into a separate branch until they are stable. It is a nice challenge both for coding skills and for const generics.
Shall I start?

[XOSplicer]

Reference #102

[burrbull]

@kpp Try if you can.
9 months have passed since my last attempt. Maybe something has changed in good way.

[korken89]

@perlindgren has done the conversion, we are just awaiting stabilization to make a PR.

[kpp]

How about make a WIP PR so no one else tries to do it on their own?

[korken89]

@perlindgren Could you make a WIP PR with the conversion work you did?

[korken89]

For reference the work is being done here: https://github.com/perlindgren/heapless/tree/const_generics

[perlindgren]

Everything is implemented and the code passes all tests.

There are some type bounds that needs to be added for ensuring power 2, I don't recall exactly. These were provided by GenericArray previously, not sure if we want to define/implement them ourselves, or if these are available elsewhere.

[tarcieri]

Perhaps I should ask on the as-slice repo, but there is a plan for it and const generics?

I ask because as of #189 heapless is now pulling in three versions of generic-array (v0.12, v0.13, v0.14)

[korken89]

Technically, when const generics lands, all code related to generic-array will disappear as there is no longer any need for it.
This is also what we have done in the port of heapless. For as-slice I will do the same and remove all the code related to generic-array and specific array size implementations.

[burrbull]

8 days before beta.

[burrbull]

Time

[korken89]

Here you can follow the work, we almost finished the port https://github.com/japaric/heapless/tree/const_generics