Special data types

    Type Description
    Callable A callable value that can be executed by passing arguments in parentheses in YQL SQL syntax.
    Resource Resource is an opaque pointer to a resource you can pass between the user defined functions (UDF). The type of the returned and accepted resource is declared inside a function using a string label. When passing a resource, YQL checks for label matching to prevent passing of resources between incompatible functions. If the labels mismatch, a type error occurs.
    Tagged Tagged is the option to assign an application name to any other type.
    Generic The data type used for data types.
    Unit Unit is the data type used for non-enumerable entities (data sources and data sinks, atoms, etc. ).
    Null Void is a singular data type with the only possible null value. It's the type of the NULL literal and can be converted to any Optional type.
    Void Void is a singular data type with the only possible "null" value.
    EmptyList A singular data type with the only possible [] value. It's the type of the [] literal and can be converted to any List type.
    EmptyDict A singular data type with the only possible {} value. It's a type of the {} literal and can be converted to any Dict or Set type.