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OpenCyphal / pycyphal

Python implementation of the Cyphal protocol stack.
https://pycyphal.readthedocs.io/
MIT License
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Can not generate dsdl packages for legacy public data types #98

Closed jxltom closed 4 years ago

jxltom commented 4 years ago

I would like to generate dsdl packages for legacy v0 data types in https://github.com/UAVCAN/public_regulated_data_types/tree/legacy-v0. I installed pyuavcan 0.6.2 and the command pyuavcan dsdl-generate-packages public_regulated_data_types/uavcan returns Error: FileNameFormatError: ....../public_regulated_data_types/uavcan/CoarseOrientation.uavcan: Invalid file name

pavel-kirienko commented 4 years ago

It's not possible by design. The syntax is slightly different, but that is not the major culprit -- that would be the fact that v0 DSDL has a tail array optimization (TAO) and v1 doesn't. This difference breaks binary compatibility.

If you want to re-use types from v0, you could just manually update them to make the v1 parser happy -- just add version numbers. For example, the source file uavcan/CoarseOrientation.uavcan would become uavcan/CoarseOrientation.1.0.uavcan. A reference to a composite type like uavcan.CoarseOrientation foo would become uavcan.CoarseOrientation.1.0 foo.

Why do you need v0 types anyway?

jxltom commented 4 years ago

Because uavcan v1 is not stable yet, some libraries such as libuavcan v1 still lacks core features such as dsdl generator.

So for now I'm going to use v0 instead until v1 is stable. I think libcanard v0 or libuavan v0 requires v0 types as well, right? For example, the master branch of libuavcan in https://github.com/UAVCAN/libuavcan is using v0 types as linked as dsdl@192295c. That's the reason why I need v0 types.

Let me know if I'm wrong, thanks!

pavel-kirienko commented 4 years ago

You are correct -- v0 implementations require v0 types.