# Week 18 & 19 Update

Hi there, for the last weeks I have been working on [implementing Fulu Specs in State Transition in zig ](https://github.com/ChainSafe/state-transition-z/pull/71) .
It already uses a lot of code from Electra with the main addition of [EIP-7917:Deterministic proposer lookahead](https://eips.ethereum.org/EIPS/eip-7917).

## What is proposer lookahead tho?

In the current design of the Ethereum Beacon Chain, for each slot a validator is chosen as the proposer. That selection uses:
- A randomness source (RANDAO) derived prior to the slot.
- A set of active validators and their effective balances (EBs) as input.
Because effective balances can change during the epoch (due to rewards, penalties, deposits, etc.), the schedule of proposers for the next epoch is not completely predictable at the start of the current epoch.

Thus comes the Proposer lookahead
- it refers to the mechanism where, at the start of each epoch, you precompute and store the list of upcoming proposers for the “current epoch + a fixed lookahead number of future epochs”. This list is stored in the beacon state as a field called proposer_lookahead.

### Spec Tests

Its still not possible to run spec tests and moreover the repo has two test runners are being tested
1. operations - Tests individual operations like attestations, deposits, slashings, etc.
2. sanity - Tests complete block/epoch processing

They are still facing 3 memory leaks .

## Next steps
- I will be working on implementing [getBlockSignatureSets](https://github.com/ChainSafe/state-transition-z/issues/72).
- Work on adding more test runners like