AMM

---

Calls

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add_liquidity

Allow users to add liquidity to a given pool

• pool: Currency pool, in which liquidity will be added
• liquidity_amounts: Liquidity amounts to be added in pool
• minimum_amounts: specifying its "worst case" ratio when pool already exists

Attributes

Name	Type
pair	(AssetIdOf<T, I>, AssetIdOf<T, I>)
desired_amounts	(BalanceOf<T, I>, BalanceOf<T, I>)
minimum_amounts	(BalanceOf<T, I>, BalanceOf<T, I>)

Python

call = substrate.compose_call(
    'AMM', 'add_liquidity', {
    'desired_amounts': (
        'u128',
        'u128',
    ),
    'minimum_amounts': (
        'u128',
        'u128',
    ),
    'pair': ('u32', 'u32'),
}
)

---

create_pool

Create of a new pool, governance only

• pool: Currency pool, in which liquidity will be added
• liquidity_amounts: Liquidity amounts to be added in pool
• lptoken_receiver: Allocate any liquidity tokens to lptoken_receiver
• lp_token_id: Liquidity pool share representative token

Attributes

Name	Type
pair	(AssetIdOf<T, I>, AssetIdOf<T, I>)
liquidity_amounts	(BalanceOf<T, I>, BalanceOf<T, I>)
lptoken_receiver	T::AccountId
lp_token_id	AssetIdOf<T, I>

Python

call = substrate.compose_call(
    'AMM', 'create_pool', {
    'liquidity_amounts': (
        'u128',
        'u128',
    ),
    'lp_token_id': 'u32',
    'lptoken_receiver': 'AccountId',
    'pair': ('u32', 'u32'),
}
)

---

remove_liquidity

Allow users to remove liquidity from a given pool

• pair: Currency pool, in which liquidity will be removed
• liquidity: liquidity to be removed from user's liquidity

Attributes

Name	Type
pair	(AssetIdOf<T, I>, AssetIdOf<T, I>)
liquidity	BalanceOf<T, I>

Python

call = substrate.compose_call(
    'AMM', 'remove_liquidity', {
    'liquidity': 'u128',
    'pair': ('u32', 'u32'),
}
)

---

update_protocol_fee

Attributes

Name	Type
protocol_fee	Ratio

Python

call = substrate.compose_call(
    'AMM', 'update_protocol_fee', {'protocol_fee': 'u32'}
)

---

update_protocol_fee_receiver

Attributes

Name	Type
protocol_fee_receiver	T::AccountId

Python

call = substrate.compose_call(
    'AMM', 'update_protocol_fee_receiver', {'protocol_fee_receiver': 'AccountId'}
)

---

Events

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LiquidityAdded

Add liquidity into pool [sender, base_currency_id, quote_currency_id, base_amount_added, quote_amount_added, lp_token_id, new_base_amount, new_quote_amount]

Attributes

Name	Type	Composition
None	T::AccountId	AccountId
None	AssetIdOf<T, I>	u32
None	AssetIdOf<T, I>	u32
None	BalanceOf<T, I>	u128
None	BalanceOf<T, I>	u128
None	AssetIdOf<T, I>	u32
None	BalanceOf<T, I>	u128
None	BalanceOf<T, I>	u128

---

LiquidityRemoved

Remove liquidity from pool [sender, base_currency_id, quote_currency_id, liquidity, base_amount_removed, quote_amount_removed, lp_token_id, new_base_amount, new_quote_amount]

Attributes

Name	Type	Composition
None	T::AccountId	AccountId
None	AssetIdOf<T, I>	u32
None	AssetIdOf<T, I>	u32
None	BalanceOf<T, I>	u128
None	BalanceOf<T, I>	u128
None	BalanceOf<T, I>	u128
None	AssetIdOf<T, I>	u32
None	BalanceOf<T, I>	u128
None	BalanceOf<T, I>	u128

---

PoolCreated

A Pool has been created [trader, currency_id_in, currency_id_out, lp_token_id]

Attributes

Name	Type	Composition
None	T::AccountId	AccountId
None	AssetIdOf<T, I>	u32
None	AssetIdOf<T, I>	u32
None	AssetIdOf<T, I>	u32

---

ProtocolFeeReceiverUpdated

Protocol fee receiver updated

Attributes

Name	Type	Composition
None	T::AccountId	AccountId

---

ProtocolFeeUpdated

Protocol fee proportion of LP fee updated.

Attributes

Name	Type	Composition
None	Ratio	u32

---

Traded

Trade using liquidity [trader, currency_id_in, currency_id_out, amount_in, amount_out, lp_token_id, new_quote_amount, new_base_amount]

Attributes

Name	Type	Composition
None	T::AccountId	AccountId
None	AssetIdOf<T, I>	u32
None	AssetIdOf<T, I>	u32
None	BalanceOf<T, I>	u128
None	BalanceOf<T, I>	u128
None	AssetIdOf<T, I>	u32
None	BalanceOf<T, I>	u128
None	BalanceOf<T, I>	u128

---

Storage functions

---

Pools

A bag of liquidity composed by two different assets

Python

result = substrate.query(
    'AMM', 'Pools', ['u32', 'u32']
)

Return value

{
    'base_amount': 'u128',
    'base_amount_last': 'u128',
    'block_timestamp_last': 'u32',
    'lp_token_id': 'u32',
    'price_0_cumulative_last': 'u128',
    'price_1_cumulative_last': 'u128',
    'quote_amount': 'u128',
    'quote_amount_last': 'u128',
}

---

ProtocolFee

How much the protocol is taking out of each trade.

Python

result = substrate.query(
    'AMM', 'ProtocolFee', []
)

Return value

'u32'

---

ProtocolFeeReceiver

Who/where to send the protocol fees

Python

result = substrate.query(
    'AMM', 'ProtocolFeeReceiver', []
)

Return value

'AccountId'

---

Constants

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GetNativeCurrencyId

Value

0

Python

constant = substrate.get_constant('AMM', 'GetNativeCurrencyId')

---

LockAccountId

Value

'hJFDU5ssbB3JU6PyvaS4DrdVosVZd4zqJcqSd4rJt1W2ekYfn'

Python

constant = substrate.get_constant('AMM', 'LockAccountId')

---

LpFee

Defines the fees taken out of each trade and sent back to the AMM pool, typically 0.3%.

Value

3000

Python

constant = substrate.get_constant('AMM', 'LpFee')

---

MaxLengthRoute

How many routes we support at most

Value

10

Python

constant = substrate.get_constant('AMM', 'MaxLengthRoute')

---

MinimumLiquidity

Minimum amount of liquidty needed to init a new pool this amount is burned when the pool is created.

It's important that we include this value in order to prevent attacks where a bad actor will create and remove pools with malious intentions. By requiring a MinimumLiquidity, a pool cannot be removed since a small amount of tokens are locked forever when liquidity is first added.

Value

1000

Python

constant = substrate.get_constant('AMM', 'MinimumLiquidity')

---

PalletId

Value

'0x7061722f616d6d70'

Python

constant = substrate.get_constant('AMM', 'PalletId')

---

Errors

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ConversionToU128Failed

Conversion failure to u128

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IdenticalAssets

Identical assets

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InsufficientAmountIn

Insufficient amount in

---

InsufficientAmountOut

Insufficient amount out

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InsufficientLiquidity

Insufficient liquidity

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InsufficientSupplyOut

Insufficient supply out.

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LpTokenAlreadyExists

LP token has already been minted

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NotAnIdealPrice

Not an ideal price ratio

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PoolAlreadyExists

Pool does not exist

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PoolDoesNotExist

Pool does not exist

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ProtocolFeeReceiverNotSet

Protocol fee receiver not set

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