Hi, > Is there a guidebook, any guidelines for writing grammar in Postgres, or any > suggestions to keep in mind? > Do we have a set of guidelines to write production rules in gram.y (for the > Bison Parser Generator) to make the grammar conflict-free and extendible in > the future?
I'm far from being an expert in compilers but my dilettante understanding is that there are two types of conflicts. Shift/reduce conflicts are resolved with operator priorities (e.g. does 1+2*3 mean 1+(2*3) or (1+2)*3). Reduce/reduce conflict means a "real" conflict and Flex/Bison should (?) warn you about those. They will not happen though as long as you use common sense. On top of that note that generally PostgreSQL follows SQL standard. If you look for guidelines "flex & bison" by John Levine [1] and "Compilers: Principles, Techniques, and Tools" by Aho, Ullman et al [2] are good reads. I'm not entirely sure if it answers your question but I hope that it's helpful. [1]: https://www.amazon.com/Flex-Bison-John-R-Levine/dp/0596155972/ [2]: https://www.amazon.com/Compilers-Principles-Techniques-Tools-2nd/dp/0321486811/ -- Best regards, Aleksander Alekseev
