Generating minimal and standard parser files
--------------------------------------------
To generate minimal and standard grammar files issue 'make generate_parsers'
from Pgpool-II/src/parser directory. This will use gram_template.y file and
will generate two grammar files. gram_minimal.y (for the minimal parser) and
gram.y (for the standard parser).

'make generate_parsers' uses sunifdef (http://www.linuxcertif.com/man/1/sunifdef/) 
utility to generate the parsers. And If the 'sunifdef' utility is present on the
the system in the standard path then the configure will automatically pick it up
by itself. But in the case when the sunifdef is not present in the default path
then you can use "--with-sunifdef=sunifdef_dir' configure switch to provide the
'sunifdef' path.

Notes on importing the PostgreSQL parser
----------------------------------------
To import the PostgreSQL parser, merge all the changes in gram_template.y file
from PostgreSQL's gram.y, and then run 'make generate_parsers' to generate
updated minimal and standard grammar files for Pgpool-II

Controlling minimal and standard parser output
-----------------------------------------------
All the code in gram_template.y file inside  #ifdef pgpool_minimal_parser section
will only gets included in the gram_minimal.y file while the code inside
#ifndef pgpool_minimal_parser section will only be included in the standard parser
file.
Similarly, the unconditional code which is not in either
#ifndef pgpool_minimal_parser or #ifdef pgpool_minimal_parser will become part of
both the parser.

Example:1
---------
#ifdef pgpool_minimal_parser
code only for the minimal parser
#else
code only for the standard parser
#endif
code for both parsers
..

Example:2
---------
#ifndef pgpool_minimal_parser
code only for the standard parser
#else
code only for the minimal parser
#endif
code for both parsers