# `EEVM.Context.Block`
[🔗](https://github.com/mw2000/eevm/blob/main/lib/eevm/context/block.ex#L1)

Block-level context — information about the block being executed, exposed
to the EVM via environment opcodes.

### Fields

| Field | Opcode | Description |
|-------|--------|-------------|
| `number` | NUMBER (0x43) | Current block number |
| `timestamp` | TIMESTAMP (0x42) | Block timestamp (seconds since epoch) |
| `coinbase` | COINBASE (0x41) | Address of the block producer |
| `gaslimit` | GASLIMIT (0x45) | Block gas limit |
| `prevrandao` | PREVRANDAO (0x44) | Previous block's RANDAO mix (post-Merge) |
| `basefee` | BASEFEE (0x48) | Block base fee from EIP-1559 |
| `blob_base_fee` | BLOBBASEFEE (0x4A) | Block blob base fee from EIP-7516 |
| `chain_id` | CHAINID (0x46) | Network ID (1=mainnet, 137=Polygon, etc.) |
| `hashes` | BLOCKHASH (0x40) | Map of recent block numbers to their hashes |
| `parent_beacon_block_root` | (no opcode) | Parent beacon block root (EIP-4788) |

### parent_beacon_block_root

Added in Cancun (EIP-4788). Not exposed through an opcode — instead, the EL
client performs a system call into the beacon-roots contract at block start
to record this value keyed by the parent block's timestamp. User contracts
then `CALL` that contract to read historical beacon roots.

### PREVRANDAO

Before The Merge, opcode 0x44 was DIFFICULTY. Post-Merge, the same opcode
returns the RANDAO mix from the Beacon Chain — a source of on-chain randomness.

# `t`

```elixir
@type t() :: %EEVM.Context.Block{
  basefee: non_neg_integer(),
  blob_base_fee: non_neg_integer(),
  chain_id: non_neg_integer(),
  coinbase: non_neg_integer(),
  gaslimit: non_neg_integer(),
  hashes: %{required(non_neg_integer()) => non_neg_integer()},
  number: non_neg_integer(),
  parent_beacon_block_root: non_neg_integer(),
  prevrandao: non_neg_integer(),
  timestamp: non_neg_integer()
}
```

# `hash`

```elixir
@spec hash(t(), non_neg_integer()) :: non_neg_integer()
```

Returns the block hash for a given block number.

Returns 0 if the block number is not in the last 256 blocks or is the
current/future block. This matches the EVM spec — BLOCKHASH can only
access the most recent 256 ancestors.

# `new`

```elixir
@spec new() :: t()
```

Creates a new block context with default values.

# `new`

```elixir
@spec new(keyword()) :: t()
```

Creates a new block context with the given overrides.

## Example

    iex> block = EEVM.Context.Block.new(number: 18_000_000, chain_id: 1)
    iex> block.number
    18000000

---

*Consult [api-reference.md](api-reference.md) for complete listing*