Hi, As you might know, some of the OpenStack projects, heat and mistral, use yaql to support flexible user input. The yaql library has been tiny and stable, thanks to the ply[1] library which is the python-written implementation of lex and yacc . However, it was declared that no further release of ply is planned[2] and the author now suggests copying it into the project[3]. The old released version has been working so far, but I'm unsure if it could survive through recent drastic changes in python package tooling. Looking at the code, it seems all codes are tagged with BSD 3-clause license[3] though the repository lacks the LICENSE file. I guess that the easiest approach is to import the codes to somewhere within yaql (like yaql._ply) and use the imported codes, with a note explaining these codes are imported from ply. This follows the suggestion by the author, but I'd like to get some guidance from TC to make sure it won't break the whole license expectation. An alternative approach is to implement our own parser, though I'm not too sure if that's feasible at least from my PoV. If we want this approach, then we need actual volunteer for it who will immediately start working on it. If neither of the two options above work, we might end up removing yaql functionality completely from OpenStack. AFAIK the one in heat was added for TripleO which was already retired so the impact may be limited, while for mistral removal could have lager impact. Thank you, Takashi [1] https://github.com/dabeaz/ply [2] https://github.com/dabeaz/ply?tab=readme-ov-file#important-notice---october-... [3] https://github.com/dabeaz/ply?tab=readme-ov-file#questions-and-answers [4] https://github.com/dabeaz/ply/blob/master/src/ply/lex.py#L10-L33 -- Takashi Kajinami irc: tkajinam github: https://github.com/kajinamit launchpad: https://launchpad.net/~kajinamit