PoC account code compilation (WIT version)

[greenhat]

Following the discussion at #28 (comment)

The goal is to try to compile the following code to the MASM below and see what parts we are missing:

use miden::{
    account,
    asset::Asset,
    note::Recipient,
    tx,
};

#[miden_account]
pub struct MyWallet;

#[miden_account]
impl MyWallet {
    pub fn recieve_asset(&mut self, asset: Asset) {
        account::add_asset(asset);
    }

    pub fn send_asset(&mut self, asset: Asset, recipient: Recipient) {
        account::remove_asset(asset);
        tx::create_note(asset, recipient);
    }
}

The above code is expected to be compiled close to the following (manually written) code:

use.miden::sat::account
use.miden::sat::tx

#! Adds the provided asset to the current account.
export.receive_asset
    exec.account::add_asset
    padw swapw dropw
end

#! Creates a note which sends the specified asset out of the current account 
#! to the specified recipient.
export.send_asset.1
    exec.account::remove_asset
    # => [ASSET, tag, RECIPIENT, ...]

    # insert 8 ZEROs into the stack right after recipient; we temporarily store one of the
    # elements of ASSET in memory to make stack manipulation easier
    push.0 swap loc_store.0 padw push.0.0.0 swapdw loc_load.0
    # => [ASSET, tag, RECIPIENT, ZERO, ZERO, ...]

    exec.tx::create_note
    # => [note_ptr, ZERO, ZERO, ...]
end

The things to check are:

• Mark the MyWallet struct as a Miden account (export marker trait in WIT vs. doc comment attribute). Keep in mind that helper methods exported in the account are to be execd in notes/tx scripts.
• Try to define the Asset as a resource in WIT;

EDIT: updated to reflect the switch to WIT.

[bobbinth]

Not sure how it might affect things, but a potentially better code on the Rust side for this would be:

use miden::{
    account,
    asset::Asset,
    note::Recipient,
    tx,
};

#[miden_account]
pub struct MyWallet;

#[miden_account]
impl MyWallet {
    pub fn recieve_asset(&mut self, asset: Asset) {
        account::add_asset(asset);
    }

    pub fn send_asset(&mut self, asset: Asset, recipient: Recipient) {
        let asset = account::remove_asset(asset); // this line is different
        tx::create_note(asset, recipient);
    }
}

This is semantically different from the version in the original post only if Asset is not Copy. So, I guess one question we should settle on is whether Asset should be Copy on the Rust side. My initial thinking is that probably it should not be, but I also haven't thought through the implications.