Compare the contents of the parsed CIF files

[vaitkus]

It was suggested a few years ago by Marcin Wojdyr that it might be interesting to compare not only the behaviour of the various CIF parsers, but also to check if the parsed content is understood in the same way. This could be done by outputting the parsed data in some common format (e.g. CIF, CIF-JSON) and comparing it with the reference output.

This seems like a time-consuming endeavour, but it might reveal some additional discrepancies in the way certain rarer syntactic constructs are handled. The initial step could be to implement the comparison for a single chosen parser and document the main features of the expected output format (e.g. CIF file with all tags ordered in alphabetical order, etc/). This would serve as a useful example for other developers who would be willing to implement something similar for the CIF parsers that they maintain.

[merkys]

I think this is a great idea. Not only would it display the differences in CIF data comprehension, but in CIF writing as well. Pretty-printing CIF outputs to make them comparable might be performed for example using COD CIF writer. By the way, not all CIF parsers have CIF writing capabilities, though.