[Ride v4 and v3] Built-in variables

⚠️ This is the documentation for the Standard library version 4 and 3. We recommend to use version 6. Go to version 6

A built-in variable is a variable of the Standard library.

List of built-in variables

#	Name	Description
1	Buy	Order type
2	CEILING DOWN FLOOR HALFDOWN HALFEVEN HALFUP UP	Rounding methods used in the log and pow functions
3	height	Blockchain height at the script execution time
4	lastBlock	Information about the last block of the blockchain at the script execution time
5	nil	Variable that contains an empty list. The variable is used for creating lists. For example, instead of: let a = [5,6] you can write: let b = 5::6::nil Lists are created using both methods. The first method is a syntactic sugar
6	NOALG MD5 SHA1 SHA224 SHA256 SHA384 SHA512 SHA3224 SHA3256 SHA3384 SHA3512	Variables that are passed as the first parameter to the rsaVerify function
7	Sell	Order type
8	this	Transaction sender address or information about the token
9	tx	Transaction or order
10	unit	Variable that contains an object of Unit type. Example 1 the deposit function transfers 5 WAVELETs to the account, that called this function. {-# STDLIB_VERSION 3 #-} {-# CONTENT_TYPE DAPP #-} {-# SCRIPT_TYPE ACCOUNT #-} @Callable(inv) func deposit() = { TransferSet([ ScriptTransfer(inv.caller, 5, unit) \# Transfer 5 WAVELETs to the inv.caller account. Instead of the token ID the unit is specified ]) } WAVES does not have a token ID; the unit is passed instead of the ID. Example 2 The assetInfo function requests information about the token by its ID. Next, the isDefined function checks that a token with this ID exists on the blockchain. {-# STDLIB_VERSION 3 #-} {-# CONTENT_TYPE EXPRESSION #-} {-# SCRIPT_TYPE ACCOUNT #-} let asset = assetInfo(base58'8LQW8f7P5d5PZM7GtZEBgaqRPGSzS3DfPuiXrURJ4AJS') token.isDefined() Instead of calling the isDefined function, you may use the equality with unit. asset != unit # Expression asset != unit is equivalent to the expression token.isDefined()