# Blockchain functions

Name	Description	Complexity
addressFromRecipient(Address\|Alias): Address	Gets the corresponding address of the alias	5
assetBalance(Address\|Alias, ByteVector): Int	Gets account balance by an asset ID	10
assetInfo(ByteVector): Asset\|Unit	Gets asset parameters by its ID	15
blockInfoByHeight(Int): BlockInfo\|Unit	Gets the information about a block by the block height	5
calculateAssetId(Issue): ByteVector	Calculates ID of the token formed by the Issue structure when executing the callable function	10
calculateDelay(ByteVector, Int, Address, Int): Int	Calculates the time delay before generating a block	1
calculateLeaseId(Lease): ByteVector	Calculates ID of the lease formed by the Lease structure when executing the callable function	1
scriptHash(Address\|Alias): ByteVector\|Unit	Returns BLAKE2b-256 hash of the script assigned to a given account	200
transactionHeightById(ByteVector): Int\|Unit	Gets the block height of a transaction	20
transferTransactionById(ByteVector): TransferTransaction\|Unit	Gets the data of a transfer transaction	60
wavesBalance(Address\|Alias): BalanceDetails	Gets account balance in WAVES	10

# addressFromRecipient(Address|Alias): Address

Gets the corresponding address of the alias.

addressFromRecipient(AddressOrAlias: Address|Alias): Address

For a description of the return value, see the Address article.

# Parameters

Parameter	Description
AddressOrAlias: Address\|Alias
Address or alias, usually tx.recipient

# Examples

let address =Address(base58'3NADPfTVhGvVvvRZuqQjhSU4trVqYHwnqjF')
addressFromRecipient(address)

# assetBalance

Gets account balance by an asset ID.

The balance takes into account payments attached to the script invocation. Transfers (ScriptTransfer) made by the current callable function do not affect the balance (however, nested invocations do).

To get the WAVES balance, use the wavesBalance function.

assetBalance(addressOrAlias: Address|Alias, assetId: ByteVector): Int

# Parameters

Parameter	Description
addressOrAlias: Address\|Alias	Address or alias of the account
assetId: ByteVector	Token ID

# Example

let address = Address(base58'3PJaDyprvekvPXPuAtxrapacuDJopgJRaU3')
let bitcoinId = base58'8LQW8f7P5d5PZM7GtZEBgaqRPGSzS3DfPuiXrURJ4AJS'
assetBalance(address, bitcoinId) # Returns Bitcoin balance

# assetInfo

Gets asset parameters by its ID.

The function does not provide parameters of WAVES.

assetInfo(id: ByteVector): Asset|Unit

For a description of the return value, see the Asset article.

# Parameters

Parameter	Description
`id`: ByteVector	Token ID

# Example

let bitcoinId = base58'8LQW8f7P5d5PZM7GtZEBgaqRPGSzS3DfPuiXrURJ4AJS'
let x = match assetInfo(bitcoinId) {
    case asset:Asset =>
        asset.decimals # 8
    case _ => throw("Can't find asset")
}

# blockInfoByHeight

Gets the information about a block by the block height.

blockInfoByHeight(height: Int): BlockInfo|Unit

For a description of the return value, see the BlockInfo article.

# Parameters

Parameter	Description
`height`: Int	Block height

# Example

let x = match blockInfoByHeight(1234567) {
    case block:BlockInfo =>
        block.generator.toString() # "3P38Z9aMhGKAWnCiyMW4T3PcHcRaTAmTztH"
    case _ => throw("Can't find block")
}

# calculateAssetId

Calculates ID of the token formed by the Issue structure when executing the callable function.

calculateAssetId(issue: Issue): ByteVector

# Parameters

Parameter	Description
`issue`: Issue	Structure that sets the parameters of the token issue

# Example

{-# STDLIB_VERSION 8 #-}
{-# CONTENT_TYPE DAPP #-}
{-# SCRIPT_TYPE ACCOUNT #-}
  
@Callable(inv)
func issueAndId() = {
  let issue = Issue("CryptoRouble", "Description", 1000, 2, true)
  let id = calculateAssetId(issue)
  (
    [
      issue,
      BinaryEntry("id", id)
    ],
    unit
  )
}

# calculateDelay

Calculates the time delay in milliseconds before block generation, according to the Fair PoS formula (with T_min = 0).

⚠️ The functions is added in Standard library version 8.

func calculateDelay(generator: Address, balance: Int): Int

# Parameters

Parameter	Description
`generator`: Address	Address whose bytes in addition to the current block's VRF are used to get the hit to be inserted into the formula
`balance`: Int	Generating balance in WAVELET to be inserted into the formula

# Example

calculateDelay(i.caller, i.caller.wavesBalance().generating)

# calculateLeaseId

Calculates ID of the lease formed by the Lease structure when executing the callable function.

calculateLeaseId(lease: Lease): ByteVector

# Parameters

Parameter	Description
`lease`: Lease	Structure that sets the lease parameters

# Example

{-# STDLIB_VERSION 8 #-}
{-# CONTENT_TYPE DAPP #-}
{-# SCRIPT_TYPE ACCOUNT #-}
  
@Callable(i)
func foo() = {
  let lease = Lease(Alias("merry"),100000000)
  let id = calculateLeaseId(lease)
  (
    [
      lease,
      BinaryEntry("lease", id)
    ],
    unit
  )
}

# scriptHash

Returns BLAKE2b-256 hash of the script assigned to a given account. Returns unit if there is no script.

The function can be used to verify that the script is exactly the same as expected.

scriptHash(addressOrAlias: Address|Alias): ByteVector|Unit

# Parameters

Parameter	Description
`addressOrAlias`: Address\|Alias	Address or alias of the account

# Example

let addr = Address(base58'3MxBZbnN8Z8sbYjjL5N3oG5C8nWq9NMeCEm')

scriptHash(addr) # Returns base58'G6ihnWN5mMedauCgNa8TDrSKWACPJKGQyYagmMQhPuja'

# transactionHeightById

Gets the block height of a transaction. Returns unit for failed transactions (see the Transaction Validation article) and transactions elided due to challenging a block (see the section Waves 1.5: Light Node).

transactionHeightById(id: ByteVector): Int|Unit

# Parameters

Parameter	Description
`id`: ByteVector	ID of the transaction

# Example

let bitcoinId = base58'8LQW8f7P5d5PZM7GtZEBgaqRPGSzS3DfPuiXrURJ4AJS'
let x = match transactionHeightById(bitcoinId) {
    case h:Int => h # 257457
    case _ => throw("Can't find transaction")
}

# transferTransactionById

Gets the data of a Transfer transaction. Returns unit for transactions elided due to challenging a block (see the section Waves 1.5: Light Node).

transferTransactionById(id: ByteVector): TransferTransaction|Unit

For a description of the return value, see the TransferTransaction article.

# Parameters

Parameter	Description
`id`: ByteVector	ID of the transfer transaction

# Example

let transferId = base58'J2rcMzCWCZ1P3SFZzvz9PR2NtBjomDh57HTcqptaAJHK'
let x = match transferTransactionById(transferId) {
    case ttx:TransferTransaction =>
        ttx.amount # 3500000000
    case _ => throw("Can't find transaction")
}

# wavesBalance

Gets all types of WAVES balances. For description of balance types, see the Account Balance article.

The balances take into account payments attached to the script invocation. Transfers (ScriptTransfer) made by the current callable function do not affect the balances (however, nested invocations do).

wavesBalance(addressOrAlias: Address|Alias): BalanceDetails

For a description of the return value, see the BalanceDetails article.

# Parameters

Parameter	Description
addressOrAlias: Address\|Alias	Address or alias of the account