Change PROCEDURE to FUNCTION in CREATE OPERATOR syntax

Since procedures are now a different thing from functions, change the
CREATE OPERATOR syntax to use FUNCTION in the clause that specifies the
function.  PROCEDURE is still accepted for compatibility.

Reported-by: Peter Geoghegan <pg@bowt.ie>
Reviewed-by: Jonathan S. Katz <jonathan.katz@excoventures.com>

3 files changed, 13 insertions, 5 deletions

diff --git a/doc/src/sgml/extend.sgml b/doc/src/sgml/extend.sgml
index a3cb064131b..d5731621e7b 100644
--- a/doc/src/sgml/extend.sgml
+++ b/doc/src/sgml/extend.sgml
@@ -1015,7 +1015,7 @@ CREATE TYPE pair AS ( k text, v text );
 CREATE OR REPLACE FUNCTION pair(text, text)
 RETURNS pair LANGUAGE SQL AS 'SELECT ROW($1, $2)::@extschema@.pair;';
 
-CREATE OPERATOR ~> (LEFTARG = text, RIGHTARG = text, PROCEDURE = pair);
+CREATE OPERATOR ~> (LEFTARG = text, RIGHTARG = text, FUNCTION = pair);
 
 -- "SET search_path" is easy to get right, but qualified names perform better.
 CREATE OR REPLACE FUNCTION lower(pair)
diff --git a/doc/src/sgml/ref/create_operator.sgml b/doc/src/sgml/ref/create_operator.sgml
index c8263437abd..d5c385c087f 100644
--- a/doc/src/sgml/ref/create_operator.sgml
+++ b/doc/src/sgml/ref/create_operator.sgml
@@ -22,7 +22,7 @@ PostgreSQL documentation
  <refsynopsisdiv>
 <synopsis>
 CREATE OPERATOR <replaceable>name</replaceable> (
-    PROCEDURE = <replaceable class="parameter">function_name</replaceable>
+    {FUNCTION|PROCEDURE} = <replaceable class="parameter">function_name</replaceable>
     [, LEFTARG = <replaceable class="parameter">left_type</replaceable> ] [, RIGHTARG = <replaceable class="parameter">right_type</replaceable> ]
     [, COMMUTATOR = <replaceable class="parameter">com_op</replaceable> ] [, NEGATOR = <replaceable class="parameter">neg_op</replaceable> ]
     [, RESTRICT = <replaceable class="parameter">res_proc</replaceable> ] [, JOIN = <replaceable class="parameter">join_proc</replaceable> ]
@@ -100,6 +100,14 @@ CREATE OPERATOR <replaceable>name</replaceable> (
   </para>
 
   <para>
+   In the syntax of <literal>CREATE OPERATOR</literal>, the keywords
+   <literal>FUNCTION</literal> and <literal>PROCEDURE</literal> are
+   equivalent, but the referenced function must in any case be a function, not
+   a procedure.  The use of the keyword <literal>PROCEDURE</literal> here is
+   historical and deprecated.
+  </para>
+
+  <para>
    The other clauses specify optional operator optimization clauses.
    Their meaning is detailed in <xref linkend="xoper-optimization"/>.
   </para>
@@ -264,7 +272,7 @@ COMMUTATOR = OPERATOR(myschema.===) ,
 CREATE OPERATOR === (
     LEFTARG = box,
     RIGHTARG = box,
-    PROCEDURE = area_equal_function,
+    FUNCTION = area_equal_function,
     COMMUTATOR = ===,
     NEGATOR = !==,
     RESTRICT = area_restriction_function,
diff --git a/doc/src/sgml/xoper.sgml b/doc/src/sgml/xoper.sgml
index 2aa7cf9b642..2f5560ac505 100644
--- a/doc/src/sgml/xoper.sgml
+++ b/doc/src/sgml/xoper.sgml
@@ -44,7 +44,7 @@ CREATE FUNCTION complex_add(complex, complex)
 CREATE OPERATOR + (
     leftarg = complex,
     rightarg = complex,
-    procedure = complex_add,
+    function = complex_add,
     commutator = +
 );
 </programlisting>
@@ -66,7 +66,7 @@ SELECT (a + b) AS c FROM test_complex;
   <para>
    We've shown how to create a binary operator here.  To create unary
    operators, just omit one of <literal>leftarg</literal> (for left unary) or
-   <literal>rightarg</literal> (for right unary).  The <literal>procedure</literal>
+   <literal>rightarg</literal> (for right unary).  The <literal>function</literal>
    clause and the argument clauses are the only required items in
    <command>CREATE OPERATOR</command>.  The <literal>commutator</literal>
    clause shown in the example is an optional hint to the query