-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Eduardo Morras wrote: | but don't know much about the VDBE code.
The opcodes and operation (stacks etc) are all well documented: ~ http://www.sqlite.org/opcode.html All the necessary opcodes are already present in that you can do checks (ge, eq, le etc), conditionals (if) and program flow (goto, gosub, return). A simple sanity check of your idea is to have some PL/SQL (or whatever language of your choice) and hand compile it into VDBE. You'll soon get a feel for whether the existing opcodes work well, or if you will need something completely different. Going from hand compilation to machine compilation is then a simple matter of programming :-) If you are unfamiliar with how to write a compiler then almost any textbook out there will do. They usually have a first section going to extraordinary length on grammars, automata, parsing and lexing etc. The good news is you can just use Lemon which is another fine drh product and used for the SQL grammar in SQLite. Pretty much every book and tutorial then shows how to emit code for a simple stack machine. Luckily enough, that is exactly what vdbe is. Later chapters will be on generating error messages, optimizations, and dealing with the fun low level things in modern CPUs, all of which you can ignore. There is even a starting grammar for you: ~ http://www.antlr.org/grammar/1107752678378/PLSQLGrammar.g Roger -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) iD8DBQFFjj0GmOOfHg372QQRAiAaAJwINxMkhdyUFKKu/fT3HGkEcjquOACeO06x WY7L3Zhh8h2YbU60oMzNC1Q= =qKyu -----END PGP SIGNATURE----- ----------------------------------------------------------------------------- To unsubscribe, send email to [EMAIL PROTECTED] -----------------------------------------------------------------------------
