Excerpts from Florian Pflug's message of mar sep 27 08:28:00 -0300 2011:
> On Sep27, 2011, at 10:44 , andurkar wrote:
> > Currently I am working on Postgresql... I need to study the gram.y and
> > scan.l parser files...since I want to do some qery modification. Can anyone
> > please help me to understand the files. What should I do ? Is there any
> > documentation available ?
>
> scan.l defines the lexer, i.e. the algorithm that splits a string (containing
> an SQL statement) into a stream of tokens. A token is usually a single word
> (i.e., doesn't contain spaces but is delimited by spaces), but can also be
> a whole single or double-quoted string for example. The lexer is basically
> defined in terms of regular expressions which describe the different token types.
Seemed a good answer so I added it to the developer's faq
http://wiki.postgresql.org/wiki/Developer_FAQ#I_need_to_do_some_changes_to_query_parsing._Can_you_succintly_explain_the_parser_files.3F
Feel free to edit.
--
Álvaro Herrera <alvherre@commandprompt.com>
The PostgreSQL Company - Command Prompt, Inc.
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