Complete the unfinished re library with group support

[mukirkland]

I am reaching out in hopes of enhancing the functionality of the re library in this Starlark third-party package.

While extensively using the Starlib library, I noticed that the re library is under development and currently lacks completeness. I found this particularly noticeable as there appear to be missing methods that prevent comprehensive utilization of re capabilities. Consequently, this limits the potential of regex processing within Starlark using Starlib.

Specifically, I was hoping for support in regex groups across all methods, which unfortunately, seems to be unsupported at the moment. Regex Groups are a critical tool in text processing, allowing for more complex pattern matching and substitution. Support for them will greatly boost the flexibility and power of the re library in the Starlib package.

This adjustment would constitute functionalities such as:

• re.match, re.search, re.findall, re.finditer should all return groups if the pattern includes groups.
• re.sub and re.subn should be able to use the matched groups in their replacement string.

Considering the potent utility of the re module in text processing, I believe that this enhanced and full functionality would greatly contribute to the usefulness and practicality of the Starlib package for the broader Starlark community.

I understand that there might already be an ongoing development for this library, and perhaps, even these features might be under consideration. If it is possible, could we get an approximate timeline for these improvements?

Thank you for your ongoing work on this project, and I look forward to hearing back from you soon.