Handcraft many bundles at once

[Nadrieril]

Fixes #64. Based on #70 for the MultiBundle goodies.

[albertsgarde]

Looks good. Instead of creating a new craft_n function, could the HandCraft::craft function be modified? Specifically can this be done while allowing no worse an interface for single crafts. I don't mind backwards incompatibility

[Nadrieril]

It could yeah, the only user change needed would be craft(..) -> craft::<1>(..). I don't think the amount will be inferrable unfortunately.

[albertsgarde]

Not inferrable, but it could default to 1 right? Think that would be a really nice interface

[Nadrieril]

Rust doesn't allow defaults for const generics in functions unfortunately

[albertsgarde]

Fair enough. I thought I had used them on Territory::hand_mine, but clearly not. Also, apparently using const generic defaults and const expressions together can ICE the compiler, so it's really not an option.

[albertsgarde]

Just tried it out to test the ergonomics and ran into an issue. The relevant part of my save is

    let mut iron = iron_furnace.outputs(&tick).0.empty();
    let mut copper = copper_furnace.outputs(&tick).0.empty();
    let (wire1,) = CopperWireRecipe::craft(&mut tick, (copper.bundle().unwrap(),));
    let (wire2,) = CopperWireRecipe::craft_n::<5>(&mut tick, (copper.bundle().unwrap(),));

and on the last line I get

error[E0275]: overflow evaluating the requirement [(); rustorio_engine::::recipe::{impl#8}::{constant#0}] well-formed
--> src/bin/test3/main.rs:46:20
|
46 | let (wire2,) = CopperWireRecipe::craft_n::<5>(&mut tick, (copper.bundle().unwrap(),));
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: required for (Bundle<CopperWire, 2>,) to implement rustorio_engine::recipe::MultiBundleMultiply<5>

I might look into it myself, but I don't have time at the moment.

[Nadrieril]

Ah shoot, I hadn't actually tried using it ><

[albertsgarde]

lol. I was very close to just merging it, but stopped myself thinking I really should try it out first

[Nadrieril]

I mean it will work if there's no inference at all, but here you're asking it to infer the bundle size and that's murky const generics shenanigans i didn't think of

[albertsgarde]

What is the intended usage?
I tried

    let (wire2,): (Bundle<CopperWire, 10>,) =
        CopperWireRecipe::craft_n::<5>(&mut tick, (copper.bundle::<5>().unwrap(),));

but got the same general error.

If even I can't immediately figure out usage we should at least include an example in the doc.

[Nadrieril]

Oh, if that doesn't work then this is useless :(

[albertsgarde]

I'd love to have the feature if we can find some way to make it work. The error is specifically for checking a requirement, so maybe there's a way to change that to make it work.

[Nadrieril]

I'm very confused, let _: (Bundle<CopperWire, 4>,) = CopperWireRecipe::craft_n::<2>(&mut tick, (bundle(),)); works for me. I added a test. Inferring the bundle size works...

[albertsgarde]

I'm still getting the error.
My reproduction

#![forbid(unsafe_code)]
#![forbid(internal_features)]

use rustorio::{
    self, Bundle, HandRecipe, Tick,
    buildings::Furnace,
    gamemodes::Standard,
    recipes::{CopperSmelting, CopperWireRecipe},
    resources::{CopperWire, Point},
};

type GameMode = Standard;

type StartingResources = <GameMode as rustorio::GameMode>::StartingResources;

fn main() {
    rustorio::play::<GameMode>(user_main);
}

fn user_main(mut tick: Tick, starting_resources: StartingResources) -> (Tick, Bundle<Point, 200>) {
    let StartingResources {
        iron,
        mut iron_territory,
        mut copper_territory,
        steel_technology,
    } = starting_resources;

    let mut copper_furnace = Furnace::build(&tick, CopperSmelting, iron);

    let copper_ore = copper_territory.hand_mine::<20>(&mut tick);
    copper_furnace.inputs(&tick).0 += copper_ore;
    tick.advance_until(|tick| copper_furnace.inputs(tick).0 == 0);
    let mut copper = copper_furnace.outputs(&tick).0;
    let copper_bundle = copper.bundle::<5>().unwrap();
    let wire: (Bundle<CopperWire, 10>,) =
        CopperWireRecipe::craft_n::<5>(&mut tick, (copper_bundle,));

    todo!("Return the `tick` and the victory resources to win the game!")
}

As you can see I've attempted to specify everything to make the compiler's job as easy as possible, but I still get

overflow evaluating the requirement `[(); rustorio_engine::::recipe::{impl#9}::{constant#0}] well-formed`
required for `(rustorio::Bundle<rustorio::resources::CopperWire, 2>,)` to implement `rustorio_engine::recipe::MultiBundleMultiply<5>`

[Nadrieril]

Wow, this was rust-lang/rust#145069. Implemented the fix suggested there.