Add block_id! macro

[lukas0008]

Added a macro which allows getting BlockId from blocks.json at compile-time.

Basic usage:

let grass_block = block_id!("minecraft:grass_block");

with block properties:

let button = block_id!(
    "minecraft:acacia_button",
    "facing" = "north",
    "powered" = "true",
    "face" = "floor"
);

[Snowiiii]

Hey, We need this for Chunks right?. Or for what usecases is this?

[lukas0008]

It's for things that involve using BlockId, currently if you want to get a block id, you call BlockId::new with the name and properties of the block you need. This is not only bad because it is ran in runtime (making it a bit slower), but mainly it is bad since you need to unwrap the result from the function, which results in error prone and messy code. The macro solves the issue by just doing it at compile time and throwing an error if something isn't right.

[Snowiiii]

Can't we refactor BlockId::new also use Compile time ?

[lukas0008]

but... how?

[StripedMonkey]

In principle it's possible to build the data as a bindgen-esque crate. I would advocate for not embedding block types/properties directly into the built binary though. Pre-generating them and caching the results somewhere feels like a better approach.

[lukas0008]

I do store the parsed blocks.json statically, in the same build it only has to be parsed once, so the compile length hit should be negligible, since each macro is literally just a hashmap lookup with a bit of logic to parse the input.

PS: the block type and properties do not get embedded into the final built binary, after the macro execution it ends up just being a BlockId