Since the beginning of the project, there have been regular requests for
support for conventional stored procedures (and triggers). This was always
postponed to some unspecified time in the future as a proper implementation
would ideally involve a rewrite of the parser and command executor parts of
the engine.

Recently Liuxin, a CS researcher, has asked to join us and work on this. I
would like to welcome Liuxin and start the ball rolling.

My proposed plan is to develop a new set of classes for the functionality
that is currently in Tokenizer, Parser, and Expression. A grammar based
approach will be taken, using JavaCC, JFlex or Antler based on our
requirements and modified if necessary.

Our initial objective would be a working implementation with a minimum set
of procedural features (conditions, loops, variables) plus the existing
level of SQL support. The procedural language should be a subset of SQL
standard Part4 (SQL/PSM).

I will coordinate this effort overall and ensure the integration of the
resulting data structures into the engine. Developers are invited to join
the effort and contribute. Some areas of work are:

- assessment of JavaCC and Antler in terms of speed and capability - the
licenses for these programs are compatible with ours and we can modify and
incorporate them. Compare to JFlex for lexer speed (very important factor in
our choice). An experimental lexer developed last year by Loic with JFlex
seemed pretty fast and comparative tests reported recently on the JFlex
mailing list showed it was much faster than Antler in tokenizing.

- any modifications to the lexer / parser as necessary

- work on grammar

- help with integration (for developers who have already worked on the core)

- help with tests

Comments are welcome.

Fred Toussi



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