A limited set of SPL types are supported.
- Primitive types
- blob - maps to a Python memoryview
- boolean - maps to Python bool
- int8, int16, int32, int64 - maps to Python int
- uint8, uint16, uint32, uint64 - maps to Python int
- float32, float64 - maps to Python float
- decimal32, decimal64, decimal128 - maps to Python decimal.Decimal
- complex32, complex64 - maps to Python complex
- rstring, ustring - maps to Python String - rstring values assume UTF-8 encoding
- timestamp - maps to Python streamsx.spl.type.Timestamp
- Collection types
- list<T> where T is any supported type. Passed into Python as a list.
- set<T> where T is any supported primitive type except blob. Passed into Python as a set. T must be primitive to match Python's requirement that an element of a set is hashable.
- map<K,V> where K is any supported primitive type expect blob and V is any supported type. Passed into Python as a dictionary. K must be primitive to match Python's requirement that a key of a map is hashable.
- optional<T> (Streams 4.3) - maps to None when not present otherwise the value mapping for T.
For details see the Python documentation.
SPL blob handling
A SPL blob value is passed into Python as a memoryview object to avoid copying the contents of the value. The memoryview object will be released after the callable returns and thus any further use of it will throw a ValueError.
Thus if the callable wants to maintain the value after the call it must copy the required information from the memoryview before returning.
The memoryview object may be safely returned by the callable as part of a tuple to be submitted.