Hello,
I've started to study the BNF grammar files of SQL92
(http://cui.unige.ch/db-research/Enseignement/analyseinfo/SQL92/BNFindex.html
and http://www.contrib.andrew.cmu.edu/%7Eshadow/sql/sql2bnf.aug92.txt).
I noticed a strange thing: the definition of identifier with rules instead of
regular expression used by the lexer. Since one lexer is very fast (compared to a
parser),
I suggest to rewrite some parts of the SQL92 grammar as made in the AxionSQLParser.jj
or SQL.jj (from Mckoi) to make the grammar more simple to read. Moreover, we will have
to
add the HSQLDB specific rules.
Here is a simple roadmap for this:
-1- rewrite the SQL92 grammar (in text or html format) and introduce lexer tokens such
as
identifier, integer, real... define states (used by the lexer) for comments and
litterals.
-2- add the HSQLDB specific rules
-3- write the lexer (use one that already exists or from scratch)
-4- write the parser (use one that already exists or from scratch)
-5- tests (SQL syntax, performance...)
steps 3-4-5 are repeated until the results are conform with the target: a fast SQL
statements analyzer.
What do you think?
Loic
note: wondersonic == loic ;o) ; personnal (week-end) versus work (week) e-mail
---------------------- Envoyà par Loic LEFEVRE/FR/EUROPE/GROUP le
30/07/2004 09:53 ---------------------------
Internet
[EMAIL PROTECTED] - 29/07/2004 22:34
Pour : Loic LEFEVRE
cc :
Objet : Re: RÃf. : RE: [Hsqldb-developers] Is there any douments about
the code?
Hi Loic,
Sure, as you said before one should start to write the grammer at some
point.
Specifically, it would be a good idea to use the names used by the SQL 92,
99 and 03 standards (you need to replace spaces with the underscore).
These you can find in the standards texts, but it seems some people have
compiled them into BNF or similar grammar files. If there is no licensing
issue, we can use such files as a starting point.
Please go to the link that Campbell posted to find an SQL92 grammar file.
(there is also a link to one on our homepage)
I think you and Liuxin could form a good partnership. You are very capable
in getting things done while it seems he is more into deep theory than
practice (he is an assistant researcher in China's Academy of Computer
Science, a highly respected institution). I won't be heavily involve in
this until it gets to the point of building expressions, which I will have
to incorporate into the rest of the engine.
Fred
----- Original Message -----
From: [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
Sent: 29 July 2004 15:53
Subject: RÃf. : RE: [Hsqldb-developers] Is there any douments about the
code?
Hello,
What do you think about it?
Loic
Internet
[EMAIL PROTECTED]@lists.sourceforge.net - 28/07/2004 23:04
Envoyà par : [EMAIL PROTECTED]
Pour : fredt, hsqldb-developers
cc :
Objet : RE: [Hsqldb-developers] Is there any douments about the code?
If you intend to write a parser for the supported HSQLDB-SQL syntax, you
should begin to write the grammar.
It will help you to identify the common parts plus it will easily help to
define the terminals for the lexer and the
regular expressions to define integers, decimals, identifiers and so on.
Here is a (very) little extract of what may be done as a first step:
Lo?c
-----Message d'origine-----
De?: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] la part de fredt
EnvoyÃ?: mercredi 28 juillet 2004 19:28
Ã?: hsqldb-developers
Objet?: Re: [Hsqldb-developers] Is there any douments about the code?
There aren't any document. Try to debug Parser.ParseSelect(...). This
calls
private methods of Parser to build the expression tree. Parser methods
call
Tokenizer methods for tokens.
Fred
----- Original Message -----
From: "liuxin" <[EMAIL PROTECTED]>
To: "hsqldb-developers" <[EMAIL PROTECTED]>
Sent: 28 July 2004 16:01
Subject: [Hsqldb-developers] Is there any douments about the code?
I dived into the source code using some test cases to debug step by step
those days ,but still confused, any documents will be appreciated!
liuxin
[EMAIL PROTECTED]
2004-07-28
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