Special data types
- Callable is a callable value that can be executed by passing, in parentheses, the arguments in the YQL SQL syntax.
- 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 is the option to assign an application name to any other type.
- Generic is the data type used for data types.
- Unit is the data type used for non-enumerable entities (data sources and data sinks, atoms, etc.).
- Null is a singular data type with the only possible null value. It's the type of the
NULLliteral and can be converted to any
- Void is a singular data type with the only possible "null" value.