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Subject: Re: Nit: "Immutable" should be "pure"
From: Brian Williams <brian.williams@mayalane.com>
In-Reply-To: <14397.1573148291@sss.pgh.pa.us>
Date: Thu, 7 Nov 2019 13:04:28 -0500
Cc: Bruce Momjian <bruce@momjian.us>,
 pgsql-docs@lists.postgresql.org
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Message-Id: <BB114B6B-7E46-443E-8C4C-8CA47F581A06@mayalane.com>
References: <157313627814.14272.6307248648194149757@wrigleys.postgresql.org>
 <20191107172830.GD12478@momjian.us> <14397.1573148291@sss.pgh.pa.us>
To: Tom Lane <tgl@sss.pgh.pa.us>
Precedence: bulk

Thanks for the feedback folks. I had not seen the IMMUTABLE argument to =
CREATE FUNCTION and realize this change is too expensive.

This probably will not be the last you hear on this since pureness and =
immutability are all the rage in development circles.  =20

> On Nov 7, 2019, at 12:38 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>=20
> Bruce Momjian <bruce@momjian.us> writes:
>> On Thu, Nov  7, 2019 at 02:17:58PM +0000, PG Doc comments form wrote:
>>> The adjective "immutable" describing the functions and operators =
used in an
>>> index (see two occurrences in doc snippet below) is incorrect and =
should be
>>> replaced with "pure".
>=20
>> I think the best we can do is to mention that IMMUTABLE functions =
mean
>> pure, but I am not sure there is even enough demand for that, vs.
>> confusing people.
>=20
> Yeah.  I don't think this terminology is nearly as universal
> as the OP believes, so I don't feel a need to change anything.
>=20
> If we adopt Corey's proposal to create a glossary [1], there'd be
> room for a parenthetical comment like "(In some circles, "pure" is the
> preferred term for this function property.)" in the glossary entry for
> "immutable".  I suspect it won't be the only entry that needs
> cross-references to other terminology.
>=20
> 			regards, tom lane
>=20
> [1] https://commitfest.postgresql.org/25/2305/