Re: I am confused after reading codes of PostgreSQL three week

From: Martijn van Oosterhout <kleptog(at)svana(dot)org>
To: hom <obsidianhom(at)gmail(dot)com>
Cc: Vaibhav Kaushal <vaibhavkaushal123(at)gmail(dot)com>, Brendan Jurd <direvus(at)gmail(dot)com>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: I am confused after reading codes of PostgreSQL three week
Date: 2011-03-20 10:08:43
Message-ID: 20110320100842.GA4525@svana.org
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On Sun, Mar 20, 2011 at 11:50:01AM +0800, hom wrote:
> I trace into scan.c because I want to known how the paser tree is
> built and I debug the source step by step.
> Then the eclipse pick up the scan.I and the excute order does not
> match the code.

Umm, the scanners produced by flex and bison are huge table driven
parsers, which makes following what is happening in terms of "parse
tree" extremely difficult to follow.

If you want to follow what's happening, see the following page:

http://dinosaur.compilertools.net/bison/bison_11.html

Which will cause the parser to dump what it's doing. As the page says,
stepping through the processed file reveals little, becuase it's the
same code being executed over and over again, only the variables
change.

Have a nice day,
--
Martijn van Oosterhout <kleptog(at)svana(dot)org> http://svana.org/kleptog/
> Patriotism is when love of your own people comes first; nationalism,
> when hate for people other than your own comes first.
> - Charles de Gaulle

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