# implementations

Source: [https://docs.curve.finance/developer/amm/legacy/factory/cryptoswap/implementations](https://docs.curve.finance/developer/amm/legacy/factory/cryptoswap/implementations)

**The CryptoSwap Factory makes use of the `create_forwarder_to` function to deploy its contracts from the implementations.**:::warning

\*\*Implementation contracts are upgradable.\*\*They can either be replaced, or additional implementation contracts can be added. Therefore, please always make sure to check the most recent ones.

:::

It utilizes three different implementations:

-   **`pool_implementation`**, containing a contract that is used to deploy the pools.
-   **`token_implementation`**, containing a contract that is used to deploy LP tokens.
-   **`gauge_implementation`**, containing a blueprint contract that is used when deploying gauges for pools.

<a id="query-implementations"></a>

## Query Implementations

<a id="pool_implementations"></a>

### `pool_implementations`

`Factory.pool_implementations() -> address: view`

Getter for the pool implementation contract.

Returns: pool implementation (`address`).

**<>Source code▼**

```vyper
pool_implementation: public(address)
```

**▶Example▼**

```shell
>>> Factory.pool_implementations()
'0xa85461AFc2DEEC01bDA23b5cd267d51F765fba10'
```

<a id="token_implementation"></a>

### `token_implementation`

`Factory.token_implementation() -> address: view`

Getter for the token implementation contract.

Returns: token implementation (`address`).

**<>Source code▼**

```vyper
token_implementation: public(address)
```

**▶Example▼**

```shell
>>> Factory.token_implementation()
'0xc08550A4cc5333f40e593eCc4C4724808085D304'
```

<a id="gauge_implementation"></a>

### `gauge_implementation`

`Factory.gauge_implementation() -> address: view`

Getter for the gauge implementation contract.

Returns: gauge implementation (`address`).

**<>Source code▼**

```vyper
gauge_implementation: public(address)
```

**▶Example▼**

```shell
>>> Factory.gauge_implementation()
'0xdc892358d55d5Ae1Ec47a531130D62151EBA36E5'
```

<a id="set-new-implementation"></a>

## Set New Implementation

*New implementations can be set via these admin-only functions:*

<a id="set_pool_implementation"></a>

### `set_pool_implementation`

`Factory.set_pool_implementation(_pool_implementation: address):`

Guarded Method

This function is only callable by the `admin` of the contract.

Function to set a new pool implementation contract.

Emits event: `UpdatePoolImplementation`

| Input | Type | Description |
| --- | --- | --- |
| `_pool_implementation` | `address` | New pool implementation |

**<>Source code▼**

```vyper
event UpdatePoolImplementation:
    _old_pool_implementation: address
    _new_pool_implementation: address

pool_implementation: public(address)

@external
def set_pool_implementation(_pool_implementation: address):
    """
    @notice Set pool implementation
    @dev Set to ZERO_ADDRESS to prevent deployment of new pools
    @param _pool_implementation Address of the new pool implementation
    """
    assert msg.sender == self.admin  # dev: admin only

    log UpdatePoolImplementation(self.pool_implementation, _pool_implementation)
    self.pool_implementation = _pool_implementation
```

**▶Example▼**

```shell
>>> Factory.set_pool_implementation("todo")
'todo'
```

<a id="set_token_implementation"></a>

### `set_token_implementation`

`Factory.set_token_implementation(_token_implementation: address):`

Guarded Method

This function is only callable by the `admin` of the contract.

Function to set a new token implementation contract.

Emits event: `UpdateTokenImplementation`

| Input | Type | Description |
| --- | --- | --- |
| `_token_implementation` | `address` | New token implementation |

**<>Source code▼**

```vyper
event UpdateTokenImplementation:
    _old_token_implementation: address
    _new_token_implementation: address

token_implementation: public(address)

@external
def set_token_implementation(_token_implementation: address):
    """
    @notice Set token implementation
    @dev Set to ZERO_ADDRESS to prevent deployment of new pools
    @param _token_implementation Address of the new token implementation
    """
    assert msg.sender == self.admin  # dev: admin only

    log UpdateTokenImplementation(self.token_implementation, _token_implementation)
    self.token_implementation = _token_implementation
```

**▶Example▼**

```shell
>>> Factory.set_token_implementation("todo")
'todo'
```

<a id="set_gauge_implementation"></a>

### `set_gauge_implementation`

`Factory.set_fee_receiver(_fee_receiver: address):`

Guarded Method

This function is only callable by the `admin` of the contract.

Function to set a new gauge implementation contract.

Emits event: `UpdateGaugeImplementation`

| Input | Type | Description |
| --- | --- | --- |
| `_gauge_implementation` | `address` | New gauge implementation |

**<>Source code▼**

```vyper
event UpdateGaugeImplementation:
    _old_gauge_implementation: address
    _new_gauge_implementation: address

gauge_implementation: public(address)

@external
def set_gauge_implementation(_gauge_implementation: address):
    """
    @notice Set gauge implementation
    @dev Set to ZERO_ADDRESS to prevent deployment of new gauges
    @param _gauge_implementation Address of the new token implementation
    """
    assert msg.sender == self.admin  # dev: admin-only function

    log UpdateGaugeImplementation(self.gauge_implementation, _gauge_implementation)
    self.gauge_implementation = _gauge_implementation
```

**▶Example▼**

```shell
>>> Factory.set_gauge_implementation("todo")
'todo'
```