Commit 89bfc54

[Array] and [Map] types can be indexed by by writing a square-bracket-enclosed expression after them. For arrays, the type of the index key has to be `u256` whereas for [Map] types it has to be equal to the key type of the map.

Example:

contract Foo:

balances: Map<address, u256>

pub fn baz(values: u256[10]):

# Assign value at slot 5

values[5] = 1000

# Read value at slot 5

let val1: u256 = values[5]

# Assign value for address zero

self.balances[address(0)] = 10000

# Read balance of address zero

let bal: u256 = self.balances[address(0)]

[_Expression_]: expressions.md

[Array]: array_types.md

[Map]: hashmap_types.md

* [Index expressions](expr_index.md)