Context
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package sigma
Height (block number) of the block which is currently being validated.
A collection of inputs of the current transaction, the transaction where selfBox is one of the inputs.
Authenticated dynamic dictionary digest representing Utxo state before current state.
A collection of outputs of the current transaction.
Box whose proposition is being currently executing
Maximum version of ErgoTree currently activated on the network.
Maximum version of ErgoTree currently activated on the network. See ErgoLikeContext class for details.
The version of ErgoTree currently executed by interpreter.
The version of ErgoTree currently executed by interpreter. See ErgoLikeContext class for details.
A collection of inputs of the current transaction that will not be spent.
Extracts Context variable by id and type.
Extracts Context variable by id and type.
ErgoScript is typed, so accessing a the variables is an operation which involves
some expected type given in brackets. Thus getVar[Int](id) expression should
evaluate to a valid value of the Option[Int] type.
For example val x = getVar[Int](10) expects the variable, if it is present, to have
type Int. At runtime the corresponding type descriptor is passed as cT
parameter.
There are three cases:
1) If the variable doesn't exist.
Then val x = getVar[Int](id) succeeds and returns the None value, which conforms to
any value of type Option[T] for any T. (In the example above T is equal to
Int). Calling x.get fails when x is equal to None, but x.isDefined
succeeds and returns false.
2) If the variable contains a value v of type Int.
Then val x = getVar[Int](id) succeeds and returns Some(v), which is a valid value
of type Option[Int]. In this case, calling x.get succeeds and returns the
value v of type Int. Calling x.isDefined returns true.
3) If the variable contains a value v of type T other then Int.
Then val x = getVar[Int](id) fails, because there is no way to return a valid value
of type Option[Int]. The value of variable is present, so returning it as None
would break the typed semantics of variables collection.
In some use cases one variable may have values of different types. To access such variable an additional variable can be used as a tag.
val tagOpt = getVar[Int](id)
val res = if (tagOpt.isDefined) {
val tag = tagOpt.get
if (tag == 1) {
val x = getVar[Int](id2).get
// compute res using value x is of type Int
} else if (tag == 2) {
val x = getVar[GroupElement](id2).get
// compute res using value x is of type GroupElement
} else if (tag == 3) {
val x = getVar[ Array[Byte] ](id2).get
// compute res using value x of type Array[Byte]
} else {
// compute `res` when `tag` is not 1, 2 or 3
}
}
else {
// compute value of res when the variable is not present
}
expected type of the variable.
zero-based identifier of the variable.
Some(value) if the variable is defined in the context AND has the given type. None otherwise
special.sigma.InvalidType exception when the type of the variable value is
different from cT.
A fixed number of last block headers in descending order (first header is the newest one)
A fixed number of last block headers in descending order (first header is the newest one)
2.0
2.0
Zero based index in inputs of selfBox.
Zero based index in inputs of selfBox. -1 if self box is not in the INPUTS collection.
Runtime representation of Context ErgoTree type. Represents data available in Sigma language using
CONTEXTglobal variable.