Hello Kay, > for my coding conventions, which are a bit unusual, to me e.g. this is the > correct function call, if every parameter is passed by keyword argument, > and the "=" signs are aligned on the maximum level. I had looked into > lib2to3, and found it terribly complex to work with visitors, to pick up > enough state information, so I dropped my idea to make an automatic source > code formatter for my preferred style. > > I think Redbaron might be much better suited to achieve that, it seems.
Yep, this is totally an use case for it. Actually you can go a level lower and directly do that with baron by writing a custom "dumper". As an example: I'm doing this very approach right now for pyfmt (which is a pretty formatter for python code, like gofmt basically) (WARNING: project is not ready yet). If you need inspiration on how to do that, you can find the code here: Old (but easier to understand but less flexible) approach: https://github.com/Psycojoker/pyfmt/blob/cf97f25138e866fb70fed7414c46801c92cbbd6e/pyfmt.py New approach I'm working on: https://github.com/Psycojoker/pyfmt/blob/5299a3f2233264ced5158a29dd1cb1d1586bfd81/pyfmt.py#L136-566 The new approach is using this data structure (which describes the order and content of every node): https://github.com/Psycojoker/baron/blob/master/baron/render.py#L114 Documentation: https://baron.readthedocs.org/en/latest/technical.html > [...] > Performance might be a red herring there, but xpath queries that make me > avoid touching nodes already properly formatted, would probably also be > faster. Most likely performance is not an issue at all. But xpath can be > run time compiled in principle. > > Let me know what you think of that. Since Baron (the AST) is lossless, as long as you do a lossless convertion between Baron and anything else you can do wathever you want. I actually wanted to do that with xml (as a "joke" to be honest with you, I don't have a very good appreciation of xml while I understand the power of some of its tools) to demonstration this property, I was not expecting people to actually request it. So, my technical opinion on the subject: * yes this is totally possible and quite easy to do, be sure to use this data structure if you want to do it yourself https://github.com/Psycojoker/baron/blob/master/baron/render.py#L114 (documentation: https://baron.readthedocs.org/en/latest/technical.html) * yes, there is quite a lot of chances that performance will take an hit * I will eventually do it (a baron <-> xml convertor lib), but this isn't very high in my todolist * as a practical solution, you will end up with a very low level data structure (just like baron) especially for modifications. Basically, you will face every low level details that I have abstracted for you in RedBaron. If you want to follow this path, I really recommend you to read RedBaron documentation first before doing so to evaluate if the price to pay is worth it. Have a nice weekend, -- Laurent Peuch -- Bram _______________________________________________ code-quality mailing list code-quality@python.org https://mail.python.org/mailman/listinfo/code-quality
