[3/x] Typed note inputs

[greenhat]

Ref #698

This PR introduces crates for on-chain and off-chain serialization. The reason for two crates instead of one is different Felt types. For off-chain, it wraps u64 and for on-chain, it wraps float.

The on-chain deserialization trait is at

compiler/felt-repr/onchain/src/lib.rs

Lines 15 to 60 in cccf958

	/// A reader that wraps a slice of `Felt` elements and tracks the current position.
	pub struct FeltReader<'a> {
	data: &'a [Felt],
	pos: usize,
	}
	impl<'a> FeltReader<'a> {
	/// Creates a new `FeltReader` from a slice of `Felt` elements.
	#[inline(always)]
	pub fn new(data: &'a [Felt]) -> Self {
	Self { data, pos: 0 }
	}
	/// Reads the next `Felt` element, advancing the position.
	#[inline(always)]
	pub fn read(&mut self) -> Felt {
	let felt = self.data[self.pos];
	self.pos += 1;
	felt
	}
	}
	/// A writer that wraps a `Vec<Felt>` and appends elements to it.
	pub struct FeltWriter<'a> {
	data: &'a mut Vec<Felt>,
	}
	impl<'a> FeltWriter<'a> {
	/// Creates a new `FeltWriter` from a mutable reference to a `Vec<Felt>`.
	#[inline(always)]
	pub fn new(data: &'a mut Vec<Felt>) -> Self {
	Self { data }
	}
	/// Writes a `Felt` element to the output.
	#[inline(always)]
	pub fn write(&mut self, felt: Felt) {
	self.data.push(felt);
	}
	}
	/// Trait for deserialization from felt memory representation.
	pub trait FromFeltRepr: Sized {
	/// Deserializes from a `FeltReader`, consuming the required elements.
	fn from_felt_repr(reader: &mut FeltReader<'_>) -> Self;
	}

The off-chain deserialization trait is at

compiler/felt-repr/offchain/src/lib.rs

Lines 18 to 59 in cccf958

	/// A reader that wraps a slice of `Felt` elements and tracks the current position.
	pub struct FeltReader<'a> {
	data: &'a [Felt],
	pos: usize,
	}
	impl<'a> FeltReader<'a> {
	/// Creates a new `FeltReader` from a slice of `Felt` elements.
	pub fn new(data: &'a [Felt]) -> Self {
	Self { data, pos: 0 }
	}
	/// Reads the next `Felt` element, advancing the position.
	pub fn read(&mut self) -> Felt {
	let felt = self.data[self.pos];
	self.pos += 1;
	felt
	}
	}
	/// A writer that wraps a `Vec<Felt>` and appends elements to it.
	pub struct FeltWriter<'a> {
	data: &'a mut Vec<Felt>,
	}
	impl<'a> FeltWriter<'a> {
	/// Creates a new `FeltWriter` from a mutable reference to a `Vec<Felt>`.
	pub fn new(data: &'a mut Vec<Felt>) -> Self {
	Self { data }
	}
	/// Writes a `Felt` element to the output.
	pub fn write(&mut self, felt: Felt) {
	self.data.push(felt);
	}
	}
	/// Trait for deserialization from felt memory representation.
	pub trait FromFeltRepr: Sized {
	/// Deserializes from a `FeltReader`, consuming the required elements.
	fn from_felt_repr(reader: &mut FeltReader<'_>) -> Self;
	}

Although they look identical the only reason for them to be in separate crates is different underlying Felt type in off-chain and on-chain code (see above). To have it defined only once the schema for user-defined types is discussed at #814.

The usage in the P2ID is at

compiler/examples/p2id-note/src/lib.rs

Lines 8 to 14 in cccf958

	#[note_script]
	fn run(_arg: Word, account: &mut Account) {
	let inputs = active_note::get_inputs();
	let target_account_id: AccountId = inputs.as_slice().into();
	let current_account = account.get_id();
	assert_eq!(current_account, target_account_id);

with the AccountId implementation derived at

compiler/sdk/base-sys/src/bindings/types.rs

Lines 5 to 6 in cccf958

	#[derive(Copy, Clone, Debug, PartialEq, Eq, FromFeltRepr)]
	pub struct AccountId {

The off-chain code is at

compiler/tests/integration-node/src/node_tests/basic_wallet.rs

Line 86 in cccf958

inputs: AccountIdFeltRepr(&alice_account.id()).to_felt_repr(),

with the implementation derived temporarily through proxy (AccountIdFeltRepr) later the miden-base::AccountId will have it derived as well.

This PR implements serialization and deserialization parts only to keep the PR size reasonable. The rest of #698 (DX, macros) will be addressed in the subsequent PR.

TODO:

• super roundtrip test suite;
• test various struct shapes;
• file a u64-related memory corruption bug;
• instead expect files make a test.dump_codes(artifact_name) that will write wat/ir/masm files somewhere (target folder?) ignored by git but not hidden from the editor;
• remove basic-wallet from miden example? Otherwise, release the SDK before updating the basic-wallet example.

[greenhat]

@bitwalker @bobbinth Following our discussion I put the current(temporary) approach with two type definitions in the PR description and made #814 for defining types only once.