Subject: Re: PL/Java 1.5.1
To: Christoph Berg <myon@debian.org>, pgsql-pkg-debian@postgresql.org
References: <20181016113214.GA3027@msg.df7cb.de>
From: Chapman Flack <chap@anastigmatix.net>
Message-ID: <5BC5DE4D.3070502@anastigmatix.net>
Date: Tue, 16 Oct 2018 08:49:17 -0400
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On 10/16/18 07:32, Christoph Berg wrote:

>> 2. You seem to be building packages for PG from 11 back to 9.3. For that
>>    range of PG versions, it would be possible to add the -Psaxon-examples
...
>>    It's actually safe to add -Psaxon-examples when building for any PG
>>    version back to 8.4. Before 8.4, those examples can't be included

> I'm not really following how that relates to the range of PG versions?
> Because it's "only" 8.4+ ?

The saxon-examples functions are declared with SQL syntax that didn't
exist pre-8.4, so they would just be rejected as syntax errors in 8.3
or 8.2.

The documentation illustrating how to call them uses named-parameter
notation with => so it works as far back as 9.5, and with a simple
substitution of := for => they can be called the same way as far back
as 9.0. But the illustrations also show FROM clauses with LATERAL or
with a function referring to earlier entries, which is only possible
in 9.3+.

So the saxon-examples PG version range dependency boils down to:

* the functions can be built and installed in any version 8.4 and up
* they are easy to use in 9.5 and up, following exactly the illustrations
    in the docs
* they are almost as easy to use in 9.3 and 9.4, changing => to :=
* from 9.2 back to 8.4, they work, but require increasing devilish
    cleverness to write SQL queries that use them.

-Chap