AST to KSY Translator

[LmpOSX]

Hello,

First of all my congratulations for this formidable job you have made.
Long time ago I developed an Asterix parser in python, which took category definitions in some JSON format I created.
Then I discovered Kaitai Struct https://kaitai.io which is a powerful declarative language for parsers, that translates/compiles/transpiles the KSY (Kaitai Struct source) to a lot of programming languages. I used it a lot and developed some little tools to inspect and analyze mainly SSR and ADS-B data during diagnostic task at my job.
Then I discovered you project, and decided to translate your AST to KSY, which I finally did (passing first to JSON). From KSY I translate to python and use the library for a graphic tool in python to visually inspect the Asterix files in any category that you have here!!.

Feel free to see and collaborate https://github.com/LmpOSX/Asterix-KSYGEN

Thank you very much for the fantastic job.

Best Regards

Luis Pequeno

[zoranbosnjak]

@LmpOSX thanks for your nice words about the project.
I have converted the issue to the discussion, to discuss it further.

I was aware of the kaitai project. In fact, there are some other projects with similar purpose:

• https://kaitai.io/, as you mentioned
• https://daffodil.apache.org/
• http://www.padsproj.org/

I have not yet explore them, but my understanding is that once you have the format description, you can use the existing tools to process data, gather statistics... It should be even more useful if you have asterix data entangled with other binary data and process them all with one tool and/or with various programming languages. However, there might be some asterix corner cases which are difficult to generalize to the structure from some other tools, which I am sure you have encountered when converting the structure. The major problem (complication) with the original asterix definition is that in some cases the structure depends on the value of some item. That means the structure description needs some programming constructs (if, case...) or the parsing itself must be performed in stages or you just ignore the corner cases and hardcode them to the application as you need them (which is what most asterix decoders/applications do).

wireshark is of course also an excelent example of multi format/protocol decoder and it has asterix support from this project. It will need some rewriting to support specs in complete.

Mr @mbeckerle contacted me a while ago in his attempt to add asterix support to daffodil project. I don't know how far he came with it. I am including him to the discussion if he might want to comment on that and maybe give some comparison between the projects.

The padsproj is another example of such format description. It is targeting haskell language which I am also interested in. However the padsproj does not seem to be actively maintained.

Anyway, it is nice to hear that you can make a good use of the project. There are some specs additions and corrections, so be sure to update from time to time. Also, please create an issue or pull request if you find any problem in the specs.

If I will ever use kaitai for asterix, I will certanly look at your Asterix-KSYGEN.