Containers

Type Declaration, example Description
List List<Type>, List<Int32> A variable-length sequence consisting of same-type elements.
Dictionary Dict<KeyType, ValueType>, Dict<String,Int32> Set of key-value pairs with a fixed type of keys and values.
Set Set<KeyType>, Set<String> A set of elements with a fixed type is a special case of a dictionary with the Void value type.
Tuple Tuple<Type1, …, TypeN>, Tuple<Int32,Double> Set of unnamed fixed-length elements with types specified for all elements.
Structure Struct<Name1:Type1, …, NameN:TypeN>, Struct<Name:String,Age:Int32> A set of named fields with specified value types, fixed at query start (must be data-independent).
Stream Stream<Type>, Stream<Int32> Single-pass iterator by same-type values, not serializable
Variant on tuple Variant<Type1, Type2>, Variant<Int32,String> A tuple known to have exactly one element filled
Variant on structure Variant<Name1:Type1, Name2:Type2>, Variant<value:Int32,error:String> A structure known to have exactly one element filled
Enumeration Enum<Name1, Name2>, Enum<value,error> A container with exactly one enumeration element selected and defined only by its name.

If needed, you can nest containers into each other in arbitrary combinations, for example: List<TupleInt32,Int32>.

In certain contexts, optional values can also be considered a container type (Optional<Type>) that behaves as a list of length 0 or 1.

To create literals of list containers, dictionary containers, set containers, tuple containers, or structure containers, you can use the operator notation. To create a variant literal over a tuple or structure, use the function Variant. To create an enumeration literal, use the function Enum.

To access container elements, use a dot or square brackets, depending on the container type.