# Blockchain functions

Name	Description	Complexity
addressFromRecipient(Address\|Alias): Address	Gets the corresponding address of the alias	100 for Standard Library version 3 5 for Standard Library version 4
assetInfo(ByteVector): Аsset\|Unit	Gets the information about a token	100 for Standard Library version 3 15 for Standard Library version 4
blockInfoByHeight(Int): BlockInfo\|Unit	Gets the information about a block by the block height	100 for Standard Library version 3 5 for Standard Library version 4
calculateAssetId(Issue): ByteVector	Calculates the ID of the asset, created by Issue structure during invoke script transaction execution	10
transactionHeightById(ByteVector): Int\|Unit	Gets the block height of a transaction	100 for Standard Library version 3 20 for Standard Library version 4
transferTransactionById(ByteVector): TransferTransaction\|Unit	Gets the data of a transfer transaction	100 for Standard Library version 3 60 for Standard Library version 4

# addressFromRecipient(Address|Alias): Address

Gets the corresponding address of the alias.

addressFromRecipient(AddressOrAlias: Address|Alias): Address

# Parameters

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

# Examples

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

# assetInfo

Gets the information about a token.

assetInfo(id: ByteVector): Аsset|Unit

# Parameters

Parameter	Description
`id`: ByteVector	ID of the token

# 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

# 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 the ID of the asset, created by Issue structure during invoke script transaction execution.

⚠️ The calculateAssetId function is added in Standard library version 4.

calculateAssetId(issue: Issue): ByteVector

# Parameters

Parameter	Description
`issue`: Issue	The structure by which the asset is formed

# Example

{-# STDLIB_VERSION 4 #-}
{-# CONTENT_TYPE DAPP #-}
{-# SCRIPT_TYPE ACCOUNT #-}
  
@Callable(inv)
func issueAndSend() = {
  let issue = Issue("CryptoRouble", "Description", 1000, 2, true)
  let id = calculateAssetId(issue)
  [
    issue,
    ScriptTransfer(inv.caller, issue.quantity, id),
    BinaryEntry("id", id)
  ]
}
 
// Result:
//   {
//     "type": "string",
//     "value": "55jbTUxWkbLbfd6Z7Wy93DcyD7xikBg5GRDmccD4s8uv",
//     "key": "id"
//   }

# transactionHeightById

Gets the block height of a transaction.

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.

transferTransactionById(id: ByteVector): TransferTransaction|Unit

# 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")
}