Converting Python Tuples / Lists into Any in PyUNO

Stephan Bergmann sbergman at
Thu May 16 07:20:14 UTC 2019

On 15/05/2019 15:27, Thomas Viehmann wrote:
> but that isn't really what this is about, it's about what sequence types 
> are expected when an any is passed.
> My intuition would be that the more specific type is better when 
> applicable, but I would value your input whether such a change would be 
> considered an improvement.

There is no "better" or "worse" here, just "right" or "wrong".  If some 
UNOIDL construct documents requirements for a type (e.g., used as an 
interface method parameter type), then any code using that construct 
must adhere to those requirements.

While it can be easy for a UNO language binding to automatically "fix 
things up" when e.g. an UNOIDL interface method has a parameter of type 
sequence<string> and the (Python) caller code passes in a Python object 
that would normally be mapped to a UNOIDL sequence<any>, there can be no 
magic fixup when the parameter is of type any and only some additional 
protocol (unknown to the language binding; e.g., some documentation of 
the UNOIDL method) dictates the requirement that a certain call of that 
method must e.g. actually pass in a sequence<string> wrapped in that any.

That is, the PyUno language binding had to make a choice how to e.g. map 
a Python tuple of strings into a UNOIDL any value.  It may be debatable 
whether the current choice (apparently mapping to a sequence<any> 
instead of, say, a sequence<string>) is useful.  Be aware that revising 
that choice is an incompatible change.  It may make writing certain 
Python code more intuitive, but at the same time it may break existing code.

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