Message-ID: <687683a11c0d8bd0466cedbcb99d098c11f31f97.camel@cybertec.at>
Subject: Re: Documentation of return values of range functions lower and
 upper
From: Laurenz Albe <laurenz.albe@cybertec.at>
To: Bruce Momjian <bruce@momjian.us>
Cc: Fujii Masao <masao.fujii@oss.nttdata.com>, jani.rahkola@iki.fi,
	pgsql-docs@lists.postgresql.org
Date: Thu, 02 Nov 2023 15:42:53 +0100
In-Reply-To: <ZUOu4maaCXivToUE@momjian.us>
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On Thu, 2023-11-02 at 10:14 -0400, Bruce Momjian wrote:
> Better, though "Is the range's upper bound unbounded?" makes me cringe.
>=20
> Oh, yeah, totally cringe, me too.=C2=A0 :-)
>=20
> > It is not the bound that is bounded or not, but the range.
> >=20
> > How about "Is the range unbounded at the upper end?" or "Does the range
> > have no upper bound?"
>=20
> I used your "end" idea to modify the patch, attached.

There are still some loose ends:

- you lost the specification whether it is the upper or the lower bound

- "Infinity" is a literal

- "-Infinity" is a very unlikely value for an upper bound

How about the attached version?

Yours,
Laurenz Albe

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diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index c76ec52c55..c2f266ea24 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -19905,7 +19905,7 @@ SELECT NULLIF(value, '(none)') ...
        </para>
        <para>
         Extracts the lower bound of the range (<literal>NULL</literal> if the
-        range is empty or the lower bound is infinite).
+        range is empty or has no lower bound).
        </para>
        <para>
         <literal>lower(numrange(1.1,2.2))</literal>
@@ -19923,7 +19923,7 @@ SELECT NULLIF(value, '(none)') ...
        </para>
        <para>
         Extracts the upper bound of the range (<literal>NULL</literal> if the
-        range is empty or the upper bound is infinite).
+        range is empty or has no upper bound).
        </para>
        <para>
         <literal>upper(numrange(1.1,2.2))</literal>
@@ -19991,7 +19991,8 @@ SELECT NULLIF(value, '(none)') ...
         <returnvalue>boolean</returnvalue>
        </para>
        <para>
-        Is the range's lower bound infinite?
+        Does the range have no lower bound?  (A lower bound of
+        <literal>-Infinity</literal> returns false.)
        </para>
        <para>
         <literal>lower_inf('(,)'::daterange)</literal>
@@ -20008,7 +20009,8 @@ SELECT NULLIF(value, '(none)') ...
         <returnvalue>boolean</returnvalue>
        </para>
        <para>
-        Is the range's upper bound infinite?
+        Does the range have no upper bound?  (An upper bound of
+        <literal>Infinity</literal> returns false.)
        </para>
        <para>
         <literal>upper_inf('(,)'::daterange)</literal>
@@ -20063,7 +20065,7 @@ SELECT NULLIF(value, '(none)') ...
        </para>
        <para>
         Extracts the lower bound of the multirange (<literal>NULL</literal> if the
-        multirange is empty or the lower bound is infinite).
+        multirange is empty has no lower bound).
        </para>
        <para>
         <literal>lower('{[1.1,2.2)}'::nummultirange)</literal>
@@ -20081,7 +20083,7 @@ SELECT NULLIF(value, '(none)') ...
        </para>
        <para>
         Extracts the upper bound of the multirange (<literal>NULL</literal> if the
-        multirange is empty or the upper bound is infinite).
+        multirange is empty or has no upper bound).
        </para>
        <para>
         <literal>upper('{[1.1,2.2)}'::nummultirange)</literal>
@@ -20149,7 +20151,8 @@ SELECT NULLIF(value, '(none)') ...
         <returnvalue>boolean</returnvalue>
        </para>
        <para>
-        Is the multirange's lower bound infinite?
+        Does the multirange have no lower bound?  (A lower bound of
+        <literal>-Infinity</literal> returns false.)
        </para>
        <para>
         <literal>lower_inf('{(,)}'::datemultirange)</literal>
@@ -20166,7 +20169,8 @@ SELECT NULLIF(value, '(none)') ...
         <returnvalue>boolean</returnvalue>
        </para>
        <para>
-        Is the multirange's upper bound infinite?
+        Does the multirange have no upper bound?  (An upper bound of
+        <literal>Infinity</literal> returns false.)
        </para>
        <para>
         <literal>upper_inf('{(,)}'::datemultirange)</literal>

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