Date: Fri, 11 Jun 2021 12:23:53 -0700
From: Andres Freund <andres@anarazel.de>
To: Peter Eisentraut <peter.eisentraut@enterprisedb.com>
Cc: David Rowley <dgrowleyml@gmail.com>,
	pgsql-hackers <pgsql-hackers@postgresql.org>
Subject: Re: automatically generating node support functions
Message-ID: <20210611192353.ugmjp2txdwp2duls@alap3.anarazel.de>
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Hi,

On 2021-06-08 19:45:58 +0200, Peter Eisentraut wrote:
> On 08.06.21 15:40, David Rowley wrote:
> > It's almost 2 years ago now, but I'm wondering if you saw what Andres
> > proposed in [1]?  The idea was basically to make a metadata array of
> > the node structs so that, instead of having to output large amounts of
> > .c code to do read/write/copy/equals, instead just have small
> > functions that loop over the elements in the array for the given
> > struct and perform the required operation based on the type.
> 
> That project was technologically impressive, but it seemed to have
> significant hurdles to overcome before it can be useful.  My proposal is
> usable and useful today.  And it doesn't prevent anyone from working on a
> more sophisticated solution.

I think it's short-sighted to further and further go down the path of
parsing "kind of C" without just using a proper C parser. But leaving
that aside, a big part of the promise of the approach in that thread
isn't actually tied to the specific way the type information is
collected: The perl script could output something like the "node type
metadata" I generated in that patchset, and then we don't need the large
amount of generated code and can much more economically add additional
operations handling node types.

Greetings,

Andres Freund